The research team, working with plant material from the ex-situ collection of the Institute of Biodiversity and Ecosystem Research at the Bulgarian Academy of Sciences, focused on Origanum vulgare subsp. hirtum, a Greek oregano famous for its pungent, carvacrol-rich chemistry. Their earlier work had shown that both a methanolic extract and an essential oil from this plant could kill peach aphids, Myzus persicae, depending on the concentration applied. The critical question they now asked was whether doses causing even low levels of aphid mortality would also harm plant cells—either by poisoning them, breaking their DNA, or triggering mutations. Any herbicide candidate, after all, must damage weeds without leaving a legacy of genetic damage in the wider environment.

To probe these effects, the researchers turned to Chlamydomonas reinhardtii, a single-celled green alga that has served as a robust workhorse of environmental mutagenesis testing for years. Its cells form colonies predictably under standard conditions, which makes it possible to measure survival with precision, and its genome responds to DNA-damaging agents in ways that are well characterized. The team prepared the essential oil by water distillation in a Clevenger apparatus and the methanolic extract by classical maceration, then analyzed both with gas chromatography–mass spectrometry, identifying components against the NIST spectral database.

The chemical profiles of the two preparations turned out to be strikingly different, and those differences foreshadowed everything that followed. The essential oil was dominated by the monoterpenoid phenol carvacrol at 74.34 percent, flanked by γ-terpinene at 10.66 percent, p-cymene at 9.46 percent, and smaller amounts of pinenes and carvacrol methyl ether. The methanolic extract told another story entirely: it was rich in primary metabolites such as glucose, fructose, and sucrose, along with rosmarinic acid at 6.06 percent and carvacrol at just 15.67 percent, supplemented by organic acids, phenolic acids, and trace flavonoids. In essence, the extract offered a diluted, chemically complex mixture, while the oil delivered a concentrated carvacrol payload.

Toxicity testing used a clonal assay based on colony-forming ability, with cells exposed to concentrations of 250, 500, 750, and 1000 parts per million. The controls behaved as hoped: neither the DMSO solvent nor the commercial insecticide Nurelle D significantly reduced algal survival compared with the negative control medium. The treatments, however, separated cleanly. The essential oil significantly reduced survival starting at 250 parts per million, with the survival fraction falling from 0.51 at the lowest dose to 0.09 at 750 parts per million. The methanolic extract only showed statistically significant killing at 750 and 1000 parts per million, its dose–response curve forming a plateau in the lower range. Calculated lethal doses made the contrast quantitative: roughly two-fold lower concentrations of essential oil were needed to achieve 20, 50, and 80 percent lethality compared with the extract.

The study’s most technically revealing experiment measured DNA double-strand breaks using constant field gel electrophoresis, a method that separates fragmented DNA from intact genomic DNA trapped in agarose wells and quantifies the fraction released. Here the two preparations diverged dramatically. The methanolic extract showed no DNA-damaging capacity at any tested concentration, with double-strand break levels indistinguishable from spontaneously arising breaks in untreated controls. The essential oil, by contrast, produced around two-fold higher levels of double-strand breaks than the negative control across the entire concentration range, with every increase statistically significant. The authors report, for the first time, this DNA-damaging capacity of oregano essential oil, and they point to the strong correlation between rising break levels and falling survival, suggesting that carvacrol, the oil’s dominant constituent, is the likely culprit.

Mutagenicity told a different story. Using a test of visible mutations, which scores surviving colonies for changes in size, morphology, and pigmentation, the team calculated a mutagenicity index for each treatment. With a spontaneous mutation level of 0.136 percent, both the extract and the essential oil yielded indices below 2, the threshold beneath which no mutagenic effect is identified. This absence of mutagenic activity aligns with earlier findings in other systems, including the Ames test and the SMART assay in fruit flies, and it matters enormously for practical applications: compounds that kill cells without corrupting their genetic instructions are far more attractive for deployment in agriculture than those that risk seeding heritable changes.

The authors propose that the divergent behavior of the two preparations flows directly from their chemical composition. The essential oil’s concentrated carvacrol content plausibly drives both its superior toxicity—roughly 1.4 to 2 times more genotoxic than the extract—and its capacity to shatter DNA, while the extract’s abundance of benign primary metabolites dilutes its active principles. They caution, however, that further experiments are needed to disentangle the contributions of major and minor constituents, since essential oils act as complex mixtures whose components may interact synergistically or antagonistically.

The findings arrive at a moment when the search for bioherbicides has acquired real urgency. Oregano essential oil already has a documented portfolio of effects—phytotoxic, antimicrobial, antifungal, insecticidal, and active against plant pathogens—and this study extends that spectrum to include concentration-dependent DNA damage in a plant model system. Paradoxically, the very aggressiveness that makes the oil a candidate green herbicide is bounded by its lack of mutagenic potential, which suggests it could suppress weeds without generating resistant or otherwise altered plant lineages in treated fields.

For now, the Bulgarian team’s work stands as a template for how biopesticide candidates should be vetted: not just for killing power against target organisms, but for the precise cellular mechanisms by which they act. An oil that breaks DNA cleanly without inducing mutations occupies a sweet spot between efficacy and safety, and as agriculture retreats from synthetic chemistry, that combination of properties may prove exactly what green technologies have been looking for. Oregano, long valued for flavoring pizzas and salads, may soon earn a second career protecting the crops it seasons.

Subject of Research: Genotoxic and mutagenic effects of oregano extract and essential oil on a model green alga

Article Title: On the mode of action of Origanum vulgare spp. hirtum methanolic extract and essential oil on Chlamydomonas reinhardtii

Article References: Todorova, M. D., Parvanova, P. N., Todorova, T. I., Dronchev, G. D., Nikolova, M. T., Berkov, S. H., & Chankova, S. G. (2022). On the mode of action of Origanum vulgare spp. hirtum methanolic extract and essential oil on Chlamydomonas reinhardtii. BioRisk, 17, 179-190. https://doi.org/10.3897/biorisk.17.77313

Image Credits: AI Generated

DOI: 10.3897/biorisk.17.77313

Keywords: oregano, essential oil, carvacrol, genotoxicity, Chlamydomonas reinhardtii, biopesticide, green chemistry, DNA damage, herbicide resistance, Origanum vulgare, mutation assay, plant protection

The research team, led by Stephanka Chankova and colleagues, set out to test a straightforward hypothesis: if carvacrol, the phenolic monoterpene that gives oregano much of its antimicrobial punch, is responsible for the herb’s toxicity, then extract fractions rich in carvacrol should be more genotoxic than those without it. Previous work by the group had already shown that a methanolic extract containing 15.67% carvacrol was less toxic than the essential oil, which packs a staggering 74.34% carvacrol. To probe this question, the scientists collected aerial parts of Greek oregano during the flowering stage from an ex-situ collection at IBER-BAS, dried them, and extracted them with methanol over 24 hours. They then used liquid-liquid partitioning with water and chloroform to split the crude extract into two chemically distinct fractions — one polar, one non-polar — each carrying a different cargo of plant metabolites.

Gas chromatography-mass spectrometry (GC/MS) analysis, performed after derivatization with N,O-bis-(trimethylsilyl)trifluoroacetamide and deconvolution using the Automated Mass Spectral Deconvolution and Identification System (AMDIS), identified 34 compounds across the two fractions. The polar fraction was dominated by sugars, organic acids, and flavonoid glycosides — sucrose alone accounted for 26.28% of the chromatogram area, with a 6-hydroxyflavone glycoside contributing another 10.07%. Glucose, fructose, myo-inositol, and caffeic acid rounded out a profile rich in hydrophilic molecules. The non-polar fraction told a completely different story. Carvacrol reigned supreme at 37.08%, accompanied by fatty acids, sterols like β-sitosterol, triterpene acids, and flavonoid aglycones such as naringenin and taxifolin. The chemical contrast between the two fractions could not have been more pronounced — and, as the bioassays would soon reveal, neither could the biological one.

To evaluate toxicity and genotoxicity, the researchers turned to Chlamydomonas reinhardtii strain 137C+, a wild-type green alga widely used as a sensitive test system in radiobiology and toxicology. Cell suspensions at the end of the exponential phase were treated for just 10 seconds with six concentrations of each fraction, ranging from 250 to 5000 ppm. The team employed a battery of complementary assays: a spot test based on colony-forming ability, a clonal survival fraction (SF) calculation, a test for visible mutations in surviving colonies, and Constant Field Gel Electrophoresis (CFGE) to measure induced DNA double-strand breaks (DSBs). Negative controls included Sager-Granick medium and DMSO, while the insecticide Nurelle D served as a positive control.

The results were striking. The polar fraction showed no concentration-dependent toxicity whatsoever — spot intensity was identical across all samples, including controls, and none of the tested concentrations reduced cell survival below that of untreated cells. Mutagenicity and DNA damage were equally absent. The non-polar fraction, however, devastated the algal population. Even at the lowest concentration of 250 ppm, cell survival plummeted by 60%, yielding a survival fraction of just 0.41 ± 0.08. At concentrations of 500 ppm and above, lethality approached 100%. No colonies survived to form spots, and the spot test revealed single colonies instead of the dense growth seen with the polar fraction — a visual testament to the non-polar fraction’s lethal potency.

The mutagenicity assay added another layer of concern. Treatment with 250 ppm of the non-polar fraction induced a mild but measurable mutagenic effect, with a mutagenic index of 4.83 ± 0.004 — dramatically higher than the near-zero values recorded for the polar fraction at all concentrations. Two types of visible mutations appeared in surviving colonies: low-size mutants, attributed to delayed cell division, and pigmental mutants, linked to point mutations in nuclear or chloroplast DNA. The absence of visible mutations at higher concentrations of the non-polar fraction was not good news — it simply reflected the fact that no cells survived to express them.

The DNA-damaging capacity of the non-polar fraction was perhaps the most alarming finding. CFGE analysis revealed well-expressed, concentration-dependent induction of double-strand breaks, escalating to strong DNA fragmentation at higher doses. The polar fraction, by contrast, showed no statistically significant elevation of DSBs at any concentration. The concentration-effect curves for survival and DSB induction were not perfectly aligned, suggesting that mechanisms beyond double-strand break formation — perhaps membrane disruption or interference with cell cycle machinery — contribute to cell death. This mirrors the team’s earlier findings with the radiomimetic drug Zeocin, where survival did not correlate perfectly with DSB levels.

What explains the stark divergence between the two fractions? The researchers point to carvacrol as the prime suspect. As a lipophilic monoterpene, carvacrol can alter the physico-chemical properties of cell membranes, facilitating its own entry into cells and potentially disrupting membrane integrity. Previous studies have shown that essential oils and non-polar extracts are better absorbed into algal cells than their polar counterparts, and carvacrol has been classified with chronic aquatic toxicity under the European Chemicals Agency’s registration dossier. Evidence for carvacrol’s genotoxic properties has also been reported in plants like lettuce and sorghum, where it affects seed germination, root length, and the plant cell cycle. The fact that carvacrol is entirely absent from the polar fraction — which showed zero genotoxicity — strengthens the case that this single compound drives the non-polar fraction’s damaging effects.

The implications ripple outward. Oregano and its essential oils are increasingly promoted as natural biopesticides, food preservatives, and antimicrobial agents, with the global market for plant-derived bioactive compounds expanding rapidly. But this study suggests that carvacrol-rich preparations may carry genotoxic risks to non-target organisms, particularly aquatic and soil-dwelling eukaryotes like algae. The findings do not diminish oregano’s value as a culinary herb — the concentrations tested here far exceed anything encountered in food — but they do warrant caution in agricultural and environmental applications where carvacrol-rich extracts could contact non-target species. As the authors note, further experiments with purified carvacrol are needed to clarify the exact mechanism of action, whether it involves direct DNA interaction, membrane-mediated damage, or disruption of DNA repair pathways. For now, the message is clear: not all fractions of a natural extract are created equal, and the chemistry of a plant’s metabolites matters as much as the plant itself.

Subject of Research: Genotoxicity of oregano extract fractions on Chlamydomonas reinhardtii

Article Title: Polar and non-polar fraction from Origanum vulgare spp. hirtum methanolic extract – differences in their bioactivity on Chlamydomonas reinhardtii test system

Article References: Todorova, M. D., Parvanova, P. N., Todorova, T. I., Nikolova, M. T., Berkov, S. H., & Chankova, S. G. (2022). Polar and non-polar fraction from Origanum vulgare spp. hirtum methanolic extract – differences in their bioactivity on Chlamydomonas reinhardtii test system. BioRisk, 17, 191-200. https://doi.org/10.3897/biorisk.17.78169

Image Credits: AI Generated

DOI: 10.3897/biorisk.17.78169

Keywords: oregano, carvacrol, genotoxicity, Chlamydomonas reinhardtii, biopesticide, DNA damage, mutagenicity, BioRisk, Polar, non-polar, fraction, Origanum

The research team, led by Biko K. Muita and John M. K. Roberts of the CSIRO Health and Biosecurity Research Unit, focused on a class of advanced dsRNA designs known as loop-ended dsRNA, or ledRNA. Unlike conventional linear dsRNA, ledRNA constructs carry single-stranded terminal loops on both ends of the double-stranded stem, protecting the vulnerable ends from exonuclease attack while preserving the double-stranded region that the cellular RNAi machinery requires. The team paired this architecture with two distinct sequence modifications: a G-U wobble design, in which all cytosines in the sense strand were substituted with thymines to create G-U wobble base pairs throughout the stem, and an asymmetric bulge design, in which a single nucleotide deletion was introduced every 22 nucleotides in the sense strand, generating a corresponding bulge on the antisense strand without altering its sequence.

These designs were tested against two Varroa genes selected from previous work. The first, Peritrophin-A-like, or Pero, encodes a chitin-binding protein involved in maintaining the peritrophic membrane in the mite gut. The second, crustacean hyperglycemic hormone, or CHH, is a neuropeptide that regulates energy metabolism, osmoregulation, and stress responses. Both genes had previously been shown to be effectively silenced with conventional dsRNA, producing moderate levels of mite mortality, making them suitable benchmarks for evaluating whether advanced designs could push RNAi efficacy further.

Stability assays revealed a dramatic improvement. In 50 percent sucrose feeding solution, conventional dsRNA degraded rapidly, with band intensity falling by roughly 35 percent within the first hour, 75 percent by three hours, and becoming undetectable by six hours. Hairpin RNA showed a moderate improvement, retaining about 25 percent intensity at six hours and remaining detectable until the nine-hour mark. In contrast, ledRNA degradation was substantially slower, retaining about 25 percent intensity at nine hours and 18 percent at ten hours, remaining approximately three-fold more abundant than conventional dsRNA between four and six hours.

A similar trend emerged following delivery into adult worker bees. Conventional dsRNA declined rapidly, falling to roughly 18 percent of the initial signal by day two and becoming undetectable by day four. The ledRNA construct decreased to about 60 percent of its initial intensity by day two, 30 percent by day three, and 15 percent by day four. The asymmetric bulge construct showed a comparable pattern, while the G-U modified dsRNA exhibited the strongest persistence, retaining approximately 58, 44, and 40 percent of its initial signal on days two, three, and four respectively. Overall, the advanced constructs exhibited significantly greater persistence than conventional dsRNA, with the G-U design showing the most robust statistical improvement.

Biological efficacy was assessed through two delivery routes. In direct immersion bioassays, mites were submerged in dsRNA solution and then transferred onto white-eye stage pupae. At 48 hours, mite mortality was higher for both gene targets with the advanced designs compared with conventional dsRNA. Relative to the untreated control, which showed 37.5 percent mortality, the asymmetric bulge designs targeting Pero and CHH significantly increased mortality by 52.5 and 37.5 percentage points respectively, followed by the G-U design targeting Pero, which increased mortality by 30 percentage points. Conventional dsRNA showed no elevation in 48-hour mortality above the untreated control for either gene.

Gene silencing measured by qPCR confirmed these biological outcomes. For Pero, significant knockdown was observed with conventional dsRNA at roughly 36 percent reduction, the G-U design at 46 percent, and most strongly with the asymmetric bulge design at 85 percent reduction. For CHH, significant silencing was only detected with the G-U design at roughly 47 percent reduction, despite the observed effects of the bulge design on mite mortality. In oral-delivery bioassays, where dsRNA was fed to adult worker bees parasitized by feeding Varroa mites, the Pero-targeting designs produced strong silencing at 72 hours: 78 percent for conventional dsRNA, 82 percent for the G-U design, and 92 percent for the bulge design. No significant silencing was detected for CHH-targeting designs at the same timepoint.

Small RNA sequencing of mites treated with the advanced designs revealed effective processing into functional siRNAs. Coverage spanned 100 percent of the target region for both genes, consistent with siRNA production being confined to the region targeted by the dsRNA design rather than distributed across the full locus. For the Pero gene, the G-U treatment produced higher-depth coverage, with mean read depth peaking at 565, while the bulge design reached 415. For CHH, the G-U design generated substantially higher-depth coverage, peaking at 5,412, compared with 587 for the bulge design. Conventional dsRNA coverage was very low for Pero and largely restricted to a narrow region for CHH. Across most size classes, antisense reads predominated for the advanced designs, with the bulge design showing 65 and 85 percent antisense reads for Pero and CHH respectively, whereas conventional dsRNA read distributions were skewed toward the sense strand.

The siRNA length distributions further highlighted design and target dependent differences. For Pero, siRNAs derived from the advanced designs showed dominant peaks at the 23 and 24 nucleotide size classes, whereas CHH-derived siRNAs exhibited a shift toward 22 and 23 nucleotide peaks. In most cases, the predominant antisense size classes were accompanied by corresponding sense peaks, consistent with Dicer processing of dsRNA into sense-antisense siRNA duplexes. The authors suggest that the presence of 24 nucleotide antisense-biased siRNA populations from the Pero-targeting designs could be evidence of RNA-dependent RNA polymerase-associated amplification, a secondary siRNA mechanism known from nematodes, although several RdRP homologs identified in Varroa require further functional investigation.

The findings provide the first demonstration of these advanced dsRNA molecules effectively targeting Varroa mites and suggest that structurally optimized designs could address key barriers to field application of RNAi-based biopesticides. The G-U design showed comparatively consistent performance, coinciding with robust target-specific siRNA production and an antisense bias, potentially because G-U wobble pairing introduces an imperfect duplex that alters substrate recognition and cleavage kinetics by arthropod Dicer-2. The asymmetric bulge design, which has been used to increase RNAi efficacy in transgenic plants by shifting siRNA size-class profiles, did not produce a discrete 22-nucleotide siRNA peak in this system, likely reflecting fundamental differences in dsRNA processing between plants and arthropods. The authors caution that confirmation in colony and field-level settings will be necessary to verify practical utility, but the laboratory results support further investigation of structurally optimized dsRNA designs for hive applications, potentially enabling more rapid knockdown of mite outbreaks with longer stability within the hive environment and honey bee host.

Subject of Research: RNAi-based pesticide engineering for Varroa destructor

Article Title: Novel dsRNA designs increase the stability and bioefficacy of RNAi-based pesticides for Varroa destructor

Article References: Muita, B. K., Damayo, J. E., Remnant, E. J., Smith, N. A., Greaves, I. K., Ghodke, A. B., Kumaran, N., & Roberts, J. M. K. (2026). Novel dsRNA designs increase the stability and bioefficacy of RNAi-based pesticides for Varroa destructor. Frontiers in Insect Science, 6, Article 1868457. https://doi.org/10.3389/finsc.2026.1868457

Image Credits: AI Generated

DOI: 10.3389/finsc.2026.1868457

Keywords: Varroa destructor, RNA interference, dsRNA, honey bee, pest control, biopesticide, ledRNA, gene silencing, Novel, designs, increase, stability

The research team set out to test whether extracts from the seeds of this hardy savanna tree could control Colletotrichum capsici, the fungus responsible for cowpea anthracnose. In Cameroon, the disease is a major driver of yield losses estimated between 45 and 85 percent, and farmers typically respond with synthetic chemical pesticides. Those products, while effective, carry well-documented drawbacks: they can be costly for smallholder farmers, and their intensive use raises concerns about environmental contamination and risks to human and animal health. Biopesticides derived from locally available plants offer a biodegradable, low-toxicity alternative, and the desert date tree has a long history of biological activity, with prior studies attributing insecticidal, fungicidal, antimicrobial, and vermicidal properties to its bark, roots, and seeds.

The trials took place in Akonolinga, in agro-ecological zone V of Cameroon, a forest zone with bimodal rainfall where the sub-equatorial climate delivers roughly 1,633 millimeters of rain per year across two rainy seasons, with average temperatures of 23 to 27 degrees Celsius and humidity around 80 percent. The site, left fallow for four years, sits on acidic, lateritic, sandy loam ferralitic soils. Researchers from the study worked with two improved cowpea varieties supplied by the Institute of Agricultural Research for Development: V1, called Tiligré, a 70-day cycle variety, and V2, Lori 24-130, which is notably resistant to insect pests. Both varieties carry strong yield potential of 1,500 to 2,000 kilograms per hectare.

The experimental design was a split-plot layout with four replicates spread over 400 square meters. The two varieties formed the main plots, while five treatments occupied randomized sub-plots: an untreated control, an aqueous seed extract, an acetone extract, a methanol extract, and a synthetic fungicide containing 80 percent maneb. Each experimental unit measured roughly 3 by 2 meters and contained three rows sown at 80 by 40 centimeter spacing. The trials ran across two growing campaigns, in 2020 and 2021, allowing the team to assess consistency under natural field conditions.

Preparing the extracts was a hands-on process. Mature desert date fruits were collected beneath the trees, stripped of their outer layers by soaking, sun-dried, and crushed to obtain the kernels. The almond-like seeds were then milled into powder. For the aqueous extract, 500 grams of powder macerated in 5 liters of water for at least 24 hours, producing a 100 gram per liter solution that was filtered through muslin cloth and loaded into a backpack sprayer with powdered soap as a wetting agent to improve adhesion to plant surfaces. The organic extracts required macerating 500 grams of powder in 2 liters of acetone or methanol at 70 degrees Celsius for 48 hours, followed by filtration and concentration in a rotary evaporator until essential oils were obtained. All extracts were diluted at a rate of 7 milliliters per liter of water before application. The pathogen itself was confirmed by culturing infected pods on potato dextrose agar and examining the fungus microscopically, where C. capsici reveals its signature gray mycelial mass, black bristles protruding from conidial masses, and unicellular, hyaline, falcate conidia.

The results were striking. By nine weeks after sowing in the 2020 campaign, disease incidence in untreated control plots climbed to 75.38 percent for Tiligré and 76.01 percent for Lori 24-130. In plots treated with the aqueous extract, incidence fell to 20.91 and 28.24 percent respectively, while acetone extract plots recorded 22.75 and 29.28 percent. The synthetic fungicide still led with 14.6 and 14.19 percent. But in the 2021 campaign, the story shifted: the aqueous, acetone, and methanol extracts all outperformed the fungicide, recording incidence as low as 19.13, 19.25, and 17.93 percent for Tiligré, compared with 25.54 percent for the maneb treatment. Control plots reached 79.06 percent. All differences were statistically significant at P less than 0.001 across varieties, treatments, and their interaction.

Severity, the degree to which leaves, stems, and pods were attacked, followed a similar trajectory. In 2021 at nine weeks after sowing, aqueous extract plots recorded severity of just 10.6 percent for Tiligré and 20.48 percent for Lori 24-130, acetone plots 12.2 and 12.3 percent, and methanol plots 11.63 and 14.39 percent. Untreated plots suffered severity of 64.14 and 59.82 percent. The fungicide plots recorded 9.78 and 9.1 percent in 2020 and 27.03 and 9.47 percent in 2021, meaning the plant extracts matched or exceeded the chemical standard in the second season. The researchers suggest the mechanism likely involves biochemical compounds in the extracts forming complexes with polysaccharides and proteins on the outer layer of fungal cells, destabilizing cell membrane function and leading to pathogen death, though the precise mode of action remains unclear.

Yields told an equally compelling story. In 2020, aqueous extract plots produced 794.05 kilograms per hectare for Tiligré and 926.63 for Lori 24-130, compared with just 518.03 and 545.055 kilograms in control plots. Acetone and methanol extracts delivered similar gains, with acetone reaching 859.15 and 860.23 kilograms per hectare. In 2021, the pattern held, with aqueous extract plots yielding 852.97 and 935.79 kilograms per hectare and acetone plots 823.69 and 961.68, against control yields of 385.37 and 760.47. The fungicide still produced the highest yields in some plots, reaching 1,050.68 kilograms per hectare for Lori 24-130 in 2021, but the plant extracts closed much of the gap. Across both campaigns, the Lori 24-130 variety proved the most productive overall.

Multivariate analyses reinforced the picture. Principal component analysis captured 86.45 percent of total variability in 2020 and 91.27 percent in 2021 on the first two axes, consistently separating untreated control plots, which clustered near high incidence and severity, from treated plots, which grouped with favorable growth parameters such as leaf number, plant height, collar diameter, and high yield. Cluster analysis produced the same dichotomy, with control treatments isolated from all extract and fungicide treatments. The data show that the desert date seed extracts reduced disease and increased yields in the same way as the chemical fungicide during both campaigns.

The findings position Balanites aegyptiaca seed extracts as a viable component of integrated pest management for cowpea anthracnose. Because the tree is locally available across the Sahel and savanna zones, its seeds can be harvested, processed, and applied by the very farmers who need them, at a fraction of the cost of imported chemicals. The extracts are biodegradable and carry low toxicity for humans and the environment, addressing the core criticisms of synthetic pesticide overuse. As cowpea continues to feed millions across Africa’s arid and semi-arid belts, where few other crops thrive, a simple water-based extract from a desert tree could prove one of the most practical tools yet for keeping anthracnose at bay and harvests secure.

Subject of Research: agricultural science

Article Title: Bio-effectiveness of Balanites aegyptiaca (L.) Del. seed extracts against Colletotrichum capsici (Syd.) Butler & Bisby causal agent of anthracnose in cowpeas ( Vigna unguiculata (L.) Walps.) under natural conditions

Article References: Tize, T., Ngatsi, P. Z., Lontsi Dida, S. L., Njome Toka, A., Songwe Atindo, T., Ndongo, E. B., Sale Essome, C., & Ndongo, B. (2024). Bio-effectiveness of Balanites aegyptiaca (L.) Del. seed extracts against Colletotrichum capsici (Syd.) Butler & Bisby causal agent of anthracnose in cowpeas (Vigna unguiculata (L.) Walps.) under natural conditions. Innovations in Agriculture, 7, 1-9. https://doi.org/10.3897/ia.2024.131803

Image Credits: AI Generated

DOI: 10.3897/ia.2024.131803

Keywords: cowpea, anthracnose, Balanites aegyptiaca, biopesticide, Colletotrichum capsici, Cameroon, plant extracts, integrated pest management, food security, sustainable agriculture, Bio-effectiveness, Balanites

The desert locust, Schistocerca gregaria, remains one of the most destructive transboundary pests on Earth, threatening agriculture across arid and semi-arid zones from North Africa to the Indo-Pakistan border. During plague periods, roughly 60 countries face risk, and traditional control has leaned heavily on fast-acting organophosphate insecticides such as chlorpyrifos. These chemicals work, but mounting environmental and human health concerns have increasingly restricted their use, pushing agencies toward integrated approaches that include the entomopathogenic fungus M. acridum. Two commercial formulations based on this fungus, Green Muscle and Novacrid, are currently available, and during the 2020–2021 Horn of Africa outbreak the biopesticide was successfully applied across several hundred thousand hectares, achieving mortality above 80 percent within two weeks.

Despite that track record, operational adoption has been hampered by two practical uncertainties. First, spore viability during storage in remote field conditions is difficult to guarantee, since control campaigns are sporadic and stockpiles may sit for years between uses. Second, efficacy under variable environmental conditions—fluctuating temperatures and structurally diverse vegetation—has remained incompletely quantified. Previous studies suggested that vegetation might either help or hinder the fungus, potentially shielding spores from solar radiation while complicating contact with locusts, but the influence of plant size and cover under real operational conditions had not been clearly resolved. The Mauritanian team set out to address both questions simultaneously, and, according to the authors, no previous published study has monitored a stored biopesticide formulation for as long as ten years.

The storage trial centered on a batch of fifty one-kilogram bags of Green Muscle powder, based on the IMI330189 strain of M. acridum, kept in a refrigerator set at 4 degrees Celsius at the National Desert Locust Control Centre. The refrigeration was far from ideal: power outages were recurrent throughout the decade. Every one to two years, the researchers withdrew a sample bag and ran germination tests, inoculating Petri dishes of malt extract or Sabouraud medium with diluted spore suspensions and incubating them for 18 to 20 hours before counting at least 300 spores under a microscope at 400 times magnification. Viability hovered consistently above 90 percent across all ten sampling points, from 98.31 percent at reception in 2014 to 96.53 percent in 2024, with no statistically significant variation over the entire storage period.

Two stress tests made the results especially compelling. One bag removed from refrigeration after two years was deliberately kept at ambient room temperature, averaging around 31 degrees Celsius, for a full year—and its spores still germinated at 96.03 percent. Another bag, taken from the fridge after three years, was transported and applied in the field over five consecutive days without any cold chain, after which residual formulation left under tree shade retained 97.53 percent viability after a further month. Notably, the field trial product had already passed the expiry date printed on its packaging by three years, yet it performed robustly. Laboratory bioassays confirmed that viability translated into virulence: nymphs treated at reception, after five years, and after ten years of storage all suffered high mortality, and even a drastically diluted dose of just 50 spores per insect—a million-fold dilution—eventually killed as many locusts as the standard dose, only with a delayed onset.

The field component took place in a desert locust breeding zone in northern Mauritania, about 70 kilometers north of Zouérat in the Tiris Zemmour region, in an area locally known as Waïd Jerjir—the wadi of Schouwia—named for the dense stands of the shrub Schouwia thebaica that dominate the landscape. As part of a campaign by a specialized Green Team focused on biopesticide applications, seven plots totaling 20 hectares were treated using hand-held Ulva+ spinning-disc sprayers calibrated to deliver 50 grams of formulation in 2 liters of gasoil per hectare, equivalent to 2.5 trillion spores per hectare. Applications ran in the early morning and late afternoon across five days, under temperatures of 23 to 26 degrees Celsius, relative humidity of 34 to 48 percent, and wind speeds of 3 to 5 meters per second—conditions the researchers judged suitable for fungal activity.

To probe the vegetation question, the team selected two contrasting three-hectare plots. Plot A held large, widely dispersed S. thebaica plants, while Plot B contained small, closely spaced individuals, a difference confirmed statistically by measurements of plant length, width, height, and spacing. Nymphs collected from both plots two days after spraying were placed in mesh cages, 50 insects per treatment, fed with uncontaminated vegetation, and monitored daily for two weeks under partial tree shade. The outcome was unambiguous: mortality after 14 days reached 82.8 percent in Plot A and 83.9 percent in Plot B, compared with just 4.3 percent among control nymphs from an untreated zone roughly ten kilometers away, where no fungal symptoms appeared in dead insects. The post-hoc analysis found no significant difference between the two plots, demonstrating that neither plant size nor cover meaningfully altered biopesticide performance.

Field observations reinforced the cage data. Nymph bands, predominantly third and fourth instars occupying areas of 3,000 to 5,000 square meters, rapidly vacated treated plots, often on the same day as treatment, likely because gregarious locusts perching on contaminated vegetation quickly accumulated lethal spore doses through direct deposition and contact. Two weeks after application, locust populations in the treated zone were visibly depleted, while in the untreated zone most nymphs had progressed to fifth instar and winged adults, forming cohesive and active bands. The authors note that the fungus typically needs suitable temperatures to act, with optimal growth between 25 and 32 degrees Celsius, and that temperatures during the study, ranging from 9 to 36 degrees Celsius, fell within the moderately favorable window described in earlier work. They also cite a comparable trial on the Italian locust that achieved similar mortality despite daytime temperatures reaching 40 degrees Celsius.

The broader implications are considerable for preventive locust management. If properly stored formulations remain effective well beyond their labeled expiry dates, national programs could stockpile biopesticides with far greater confidence, a critical advantage in regions where campaigns are irregular and cold-chain infrastructure is unreliable. Vegetation independence likewise matters, because desert locust habitats span everything from sparse desert scrub to lush wadi vegetation, and the fungus now appears dependable across that spectrum. The authors caution that challenges remain: fungal spores can persist on vegetation for months, but residual activity in the field is still poorly characterized, and improving persistence is a recognized priority for wider adoption. A deeper obstacle, they note, is the lingering perception among decision-makers that biopesticides are less effective than chemical insecticides—a perception this study, with its decade-long storage data and consistent 80-percent-plus field mortality, directly challenges. The team calls for future work to define more precise profiles of efficacy and persistence under diverse operational conditions, paving the way for the systematic integration of M. acridum into routine desert locust control.

Subject of Research: Long-term storage stability and field efficacy of the fungal biopesticide Metarhizium acridum for desert locust control

Article Title: Ten-year storability and field efficacy of the biopesticide Metarhizium acridum in desert locust management

Article References: Etheimine, M. O., Maeno, K. O., Ely, S. O., Benahi, A. S., Jaavar, M. E. H., & Ebbe, M. A. (2026). Ten-year storability and field efficacy of the biopesticide Metarhizium acridum in desert locust management. Journal of Orthoptera Research, 35(1), 209-214. https://doi.org/10.3897/jor.35.180737

Image Credits: AI Generated

DOI: 10.3897/jor.35.180737

Keywords: Metarhizium acridum, desert locust, biopesticide, biological control, spore viability, Schistocerca gregaria, Mauritania, Green Muscle, entomopathogenic fungi, locust management, storage stability, field efficacy

The research team, working between September 2022 and April 2023, combined laboratory trials at the university’s Plant Disease Diagnostic Clinic and IPM Laboratory with a field experiment at the Department of Plant Pathology’s Field Laboratory. They used a Randomized Complete Block Design with three replicates and tested three eggplant varieties: BAU Begun-1, BAU Begun-2 and BARI Begun-5. The pathogen was isolated from naturally wilted eggplants, surface sterilized with 10% sodium hypochlorite and purified through an oozing test. In the field, plants were inoculated once at the flowering stage and again at the fruiting stage using the collar region inoculation method, in which the bacterial suspension is introduced at the collar, the junction between stem and roots.

The Trichoderma suspension, prepared at a concentration of 5.8 × 10⁷ colony-forming units per millilitre, was applied to the rhizosphere, the narrow zone of soil surrounding the roots where microbes and plant roots interact. Half of the plants in each plot received the treatment 48 hours before pathogen inoculation and the other half 48 hours after, at rates of either 20 or 40 millilitres per plant. The researchers recorded symptom expression every three days for 21 days after inoculation, counting total, inoculated, wilted and recovered plants per plot. Disease severity was scored on a 0–5 rating scale following the method of Rahman and Haque, and infection levels were expressed as percentages.

In the laboratory, the antagonistic potential of the fungus was evaluated in dual culture on potato dextrose agar. Trichoderma asperellum CP (IPM 33) achieved complete inhibition of Ralstonia solanacearum f. sp. melongenae growth, blocking the bacterium entirely when the two organisms shared a plate. The authors note that colonies of the virulent strain became visible on nutrient agar within 48 to 72 hours, appearing white or cream-colored, irregularly round, fluidal and opaque with a pinkish center. This 100% in vitro inhibition, they argue, supports the fungus’s candidacy as a biological control agent and provides a mechanistic basis for the field results.

The field data revealed striking differences among the three varieties. Percent wilting ranged from 25 to 33.33%. BARI Begun-5 proved the most susceptible at 33.33%, BAU Begun-1 the most resistant at 25%, and BAU Begun-2 fell in between at 29.17%. Notably, recovery of wilted plants was observed only in BAU Begun-2; neither BAU Begun-1 nor BARI Begun-5 recovered from infection under any treatment. During the pathogenicity test, BARI Begun-5 showed symptoms first at the flowering stage, progressing from slow drooping to quick drooping, while BAU Begun-1 took longer to develop symptoms, indicating relative resistance. At the fruiting stage, no symptoms appeared even in control plots, suggesting that susceptibility depends on the plant’s growth stage.

Timing of application emerged as a decisive factor. When no Trichoderma was applied, wilting reached 83.33%. Pre-inoculation application produced the lowest wilting percentage, 22.22%, and the highest recovery rate, 12.50%, both significantly different from other treatments. Post-inoculation application reduced wilting to 36.11% with 7.69% recovery. The authors attribute this preventive effect to thorough colonization of the rhizosphere by Trichoderma before the bacterium can establish itself. When the suspension was applied after inoculation, parts of the rhizosphere had already been colonized by Ralstonia, limiting the biocontrol agent’s ability to intervene. Similar timing effects have been reported previously in tomato.

Dosage also mattered. Wilting percentages ranged from 19.44 to 83.33% across dose treatments. The 40 millilitres per plant rate produced the lowest wilting, 19.44%, and was the only dose at which recovery occurred, reaching 28.57%. The 20 millilitres per plant rate reduced wilting to 38.89% but produced no recovery. The authors suggest that the higher dose reduced the growth rate of Ralstonia in the rhizosphere, and they draw parallels with earlier work showing that Trichoderma harzianum reduces chlamydospore germination in Fusarium oxysporum. These dose-dependent responses, they conclude, indicate that optimizing application rates is crucial for maximizing biocontrol efficacy in the field.

Growth stage shaped the outcome as well. Wilting was significantly lower at the fruiting stage, 19.44%, than at the flowering stage, 27.78%, while untreated controls reached 83.33%. Recovery of wilted plants was possible only at the flowering stage, at a rate of 10%, and was absent at the fruiting stage. The interaction analysis showed that for BAU Begun-1, applying 40 millilitres per plant as a pre-inoculation treatment at both stages produced no disease at all, while the other two varieties wilted at rates between 6.67 and 12.50% across all factor combinations. Recovery was observed only in BAU Begun-2 at the flowering stage with the 40 millilitres per plant dose, for both pre- and post-inoculation treatments. The combined influence of varietal resistance, optimal dosage, growth stage and application timing illustrates the multifactorial nature of effective disease suppression.

The authors frame the findings in the context of growing global demand for safe food and organic farming methods. Chemical pesticides, they note, can harm beneficial organisms and raise human and animal health concerns, whereas Trichoderma is a naturally occurring soil fungus that produces trichodermin, an antagonistic compound, and can also boost plant growth, enhance nutrient uptake and fortify plant resistance. An organic formulation containing the fungus, they argue, has the potential to substitute or minimize chemical pesticide use in managing eggplant wilt while creating a safer environment for growers.

The study also points to future directions. The authors call for research on the field-level consistency of Trichoderma efficacy across diverse agro-ecological zones and cropping systems, and for molecular studies to clarify the mechanisms underlying varietal resistance and rhizosphere colonization. Such work, they suggest, would support the development of more robust biocontrol solutions. For now, the results offer eggplant growers a concrete, evidence-based option: apply Trichoderma asperellum suspension before the pathogen arrives, at the higher dose tested, and pair it with moderately resistant varieties such as BAU Begun-2 to give wilted plants their best chance of recovery.

Subject of Research: Trichoderma asperellum biopesticide reduces bacterial wilt in eggplants in Bangladesh field trials.

Article Title:  Trichoderma to the rescue: Overcoming bacterial wilt in eggplants with a natural biopesticide

Article References: Harun-Or-Rashid, M., Abu Hasan, M., Kobir, M. S., Uddine Khan, M. S., & Meah, M. B. (2025). Trichoderma to the rescue: Overcoming bacterial wilt in eggplants with a natural biopesticide. Innovations in Agriculture, 8, 1-7. https://doi.org/10.3897/ia.2025.145975

Image Credits: AI Generated

DOI: 10.3897/ia.2025.145975

Keywords: Trichoderma asperellum, bacterial wilt, eggplant, Ralstonia solanacearum, biopesticide, biological control, Bangladesh, sustainable agriculture, Trichoderma, rescue, Overcoming, bacterial

The plant itself is a study in versatility. Native to tropical America and now naturalized across Asia, Africa, and beyond, Jatropha curcas is a diploid shrub or small tree that typically grows three to six meters tall, though it can reach ten meters under ideal conditions. It tolerates temperatures from 15 to 40 degrees Celsius, thrives in degraded soils with pH between 6.0 and 8.0, and survives on as little as 600 millimeters of annual rainfall. Its deep and lateral root systems stabilize soil and reduce erosion, which is why farmers have long planted it as a living fence. The genus name itself hints at its reputation: it derives from the Greek words iatros, meaning doctor, and trophe, meaning food. Monoecious greenish-yellow flowers, pollinated mainly by moths and bees, give way to trilocular fruits containing black seeds whose oil content ranges from roughly 13 to 42 percent, rich in unsaturated fatty acids such as oleic and linoleic acid.

Chemically, the plant is a treasure chest whose contents vary by organ, geography, growth stage, and extraction method. Polar solvents such as methanol, ethanol, and water efficiently pull out phenolics and flavonoids, including apigenin, vitexin, isovitexin, quercetin, luteolin, catechin, and gallic acid, while non-polar solvents like hexane and chloroform better recover fatty acids, sterols, and terpenoids. The stem bark is particularly rich in triterpenes and sterols such as amyrins, sitosterol, and taraxerol. The latex contains curcain, a proteolytic cyclic octapeptide, and curcacycline A, another cyclic peptide with immunosuppressive interest. Seeds harbor lipase, lectins, the ribosome-inactivating protein curcin, and the notorious phorbol esters. The defatted meal is strikingly protein-rich at 58 to 66 percent, though it also carries 9 to 11 percent phytate, saponins, and trypsin inhibitors that complicate any nutritional use.

The pharmacological evidence assembled in the review is remarkably broad. Antioxidant assays tell a consistent story: methanolic leaf extracts scavenged DPPH radicals with an IC50 of about 45 micrograms per milliliter, comparable to ascorbic acid, while ethanolic stem bark extracts showed moderate ABTS scavenging and aqueous leaf extracts displayed ferric reducing power near 390 micromolar iron equivalents per gram. Anti-inflammatory activity has been demonstrated in TPA-induced ear edema in mice and carrageenan-induced paw edema in rats, with methanolic root fractions reducing prostaglandin synthesis through interference with the cyclooxygenase pathway and limiting leukocyte migration and granuloma formation.

Wound healing results are among the most clinically suggestive. In an excision wound model in albino rats, ointments containing methanolic leaf extract at 1.5 grams per 10 grams of base achieved full wound closure by day 21 and shortened the epithelialization period to 14.8 days versus 18.8 days in controls, matching the performance of 1 percent gentamicin ointment. Anti-ulcer activity followed a similar pattern: oral doses of 100 and 200 milligrams per kilogram in pylorus-ligated and aspirin-challenged Wistar rats reduced gastric volume, acidity, and ulcer index, with the higher dose rivaling ranitidine and histopathology confirming preserved mucosal integrity. The authors attribute these gastroprotective effects to cytoprotective and antioxidant constituents in the leaves.

Antimicrobial and antiparasitic findings extend the plant’s promise into infectious disease. Extracts from leaves, bark, roots, seeds, seed cake, and latex, prepared with aqueous and organic solvents alike, inhibited both Gram-positive and Gram-negative bacteria and fungi. Methanolic root extracts were the standouts, producing inhibition zones of 35.1, 30.0, and 29.6 millimeters against Pasteurella multocida, Escherichia coli, and Staphylococcus aureus respectively, with minimum inhibitory concentrations between 12.5 and 30.8 milligrams per milliliter. Fresh latex blocked the development and hatching of Ascaris lumbricoides and Necator americanus eggs over 21 days of exposure and significantly slowed mosquito larval growth, while seed oil and seed cake extracts suppressed plant-pathogenic fungi including Colletotrichum coccodes, Pythium ultimum, Phytophthora capsici, Rhizoctonia solani, Bipolaris oryzae, and Fusarium fujikuroi.

Metabolic and organ-protective effects round out the pharmacological picture. In alloxan-induced diabetic Wistar rats, a 50 percent ethanolic leaf extract lowered blood glucose in a dose-dependent fashion, from 219.5 to 116.5 milligrams per deciliter at 250 milligrams per kilogram and from 237.0 to 98.83 at 500 milligrams per kilogram, the latter comparable to the standard drug glibenclamide. Acute toxicity testing under OECD Guideline 423 yielded an LD50 of 2500 milligrams per kilogram, suggesting a relatively safe profile for the leaf preparation. Separately, an ethanolic root extract protected rats against acetaminophen-induced liver injury, significantly reducing serum ALT, AST, alkaline phosphatase, and bilirubin while restoring protein and albumin levels and preserving hepatocyte architecture, an effect credited to flavonoids, phenolics, tannins, saponins, and alkaloids with free radical scavenging capacity. Methanolic leaf extracts also produced dose-dependent analgesia in tail-flick, hot plate, and acetic acid writhing tests, acting on both central and peripheral pain pathways at levels comparable to aspirin.

Two findings illustrate the plant’s chemical double edge. Its latex both promotes and delays blood clotting depending on dose and fraction: ethyl acetate fractions showed procoagulant activity at low doses, shortening human clotting times, while butanol fractions prolonged clotting and produced the strongest anticoagulant effect. And fruit extracts given to pregnant rats between the sixth and eighth days of gestation caused fetal resorption, indicating abortifacient activity at an early post-implantation stage, consistent with the plant’s traditional use as a contraceptive. Meanwhile, the methanolic root extract showed genuine anticancer potential against HT-29 human colon adenocarcinoma cells, with an IC50 of 18.3 micrograms per milliliter, comfortably below the National Cancer Institute’s 30 microgram threshold, and comparatively lower toxicity toward normal Chang liver cells at 33.3 micrograms per milliliter, though latex itself proved considerably toxic to normal liver cells.

Beyond medicine, the review highlights environmental applications that could prove equally consequential. Seed oil and seed extracts, driven mainly by phorbol esters, killed agricultural insect pests, inhibited their feeding, reduced oviposition, and impaired larval development across contact toxicity, antifeedant, larvicidal, ovicidal, fumigation, and repellency bioassays, positioning the plant as an eco-friendly alternative to synthetic insecticides. Seed-derived protein coagulants also clarified water: NaCl-based extraction yielded the most active coagulating compounds and superior turbidity removal across a broad range of conditions, including synthetic wastewater at 770 NTU, and ultrasound-assisted extraction shortened processing time, though conventional extraction remained more cost-effective.

The toxicity section is where enthusiasm meets caution. Phorbol esters, tetracyclic diterpenoids that activate protein kinase C by mimicking diacylglycerol, are the principal toxic agents, oil-soluble and distributed through kernels, leaves, bark, and stems but absent from latex. When researchers dissected kernels into their component tissues, the endosperm concentrated 96.5 percent of the phytate, 95.3 percent of trypsin inhibitor activity, and 85.7 percent of the phorbol esters. Acute LD50 values for phorbol ester fractions in mammals fall between 27 and 29 milligrams per kilogram, and chronic studies add further warnings: 28-day dosing of seed oil in mice caused growth retardation only at the highest dose of 500 milligrams per kilogram per day, but a 45-day leaf extract study killed 21 of 30 mice, though phorbol ester content was never measured, limiting interpretation. Detoxification efforts have so far met limited success, yet the same compounds that make the seeds dangerous also show antimicrobial, antitumor, insecticidal, and molluscicidal activity, suggesting biopesticide applications. The review’s verdict is measured: Jatropha curcas is a genuine repository of drug-like chemistry with proven effects spanning antioxidant, anti-inflammatory, antimicrobial, anticancer, antidiabetic, hepatoprotective, wound-healing, analgesic, and coagulation-modulating activities, but translating any of it into safe herbal medicines will require rigorous compound identification, improved extraction methods, and well-designed animal and clinical studies to establish where healing ends and harm begins.

Subject of Research: Phytochemistry and pharmacological bioactivities of the medicinal plant Jatropha curcas L.

Article Title: A comprehensive review on the phytochemical constituents and bioactivities of Jatropha curcas L.

Article References: Singh, M., Chandra, P., Kanti, Bisen, V., Namdeo, K. P., & Beck, N. R. (2026). A comprehensive review on the phytochemical constituents and bioactivities of Jatropha curcas L.. Discover Chemistry, 3(1), Article 578. https://doi.org/10.1007/s44371-026-01017-5

Image Credits: AI Generated

DOI: 10.1007/s44371-026-01017-5

Keywords: Jatropha curcas, phytochemistry, phorbol esters, antimicrobial activity, anticancer, antidiabetic, wound healing, antioxidant, biopesticide, toxicity, Euphorbiaceae, natural products

The team, led by Mst. Samia Sultana of Hokkaido University’s Graduate School of Agriculture, ran their trial during the late spring season from April 15 to August 20, 2024, at the university’s Field Science Center for the Northern Biosphere in Hokkaido. They grew the popular Japanese cabbage variety ‘Kinkei-201’ in a randomized complete block design, with each of three treatments replicated three times across plots of 24 plants. One group of plants was sprayed with the bottle gourd leaf extract dissolved in dilute dimethyl sulfoxide, a second received the chemical insecticide permethrin 3.2 EC as a positive control, and a third received only the aqueous DMSO carrier as a negative control. Spraying began ten days after transplanting and continued at seven-day intervals until the end of the growing season, for a total of eight applications at ten milliliters per plant.

The results were striking. Compared with the untreated control, the bottle gourd extract reduced looper larval infestation by 41.18 percent in the fifth week, 39.71 percent in the sixth, 52.08 percent in the seventh, and 37.96 percent in the eighth week of monitoring. Permethrin still delivered the strongest protection overall, but the botanical extract was not far behind where it mattered most: at the harvest. The extract-treated plots produced 48.26 metric tons of cabbage per hectare, essentially identical to the 48.23 metric tons per hectare achieved with permethrin, while the control plots yielded only 41.61 metric tons per hectare. That difference translates to a 15.98 percent yield increase over the control, driven almost entirely by the extract’s ability to keep hungry caterpillars at bay.

The cabbage looper earns its ominous name from the looping gait of its caterpillars, which arch their bodies as they crawl across leaf surfaces. It is among the most troublesome pests of cruciferous crops worldwide, and it is most damaging once cabbage enters the heading stage, when larvae chew through the undersides of leaves and burrow into the developing head. A single female moth can lay between 300 and 600 eggs over roughly ten to twelve days, and in warm conditions the insect can complete its entire life cycle from egg to adult in as little as 18 to 25 days. Mature larvae are voracious, eventually consuming up to three times their body weight in plant tissue each day. During the Hokkaido trial, the looper was the only pest present in meaningful numbers, making it an ideal target for a controlled comparison of treatments.

Preparing the extract was a straightforward affair that farmers in many regions could plausibly replicate. The researchers collected bottle gourd leaves on the Hokkaido University campus, discarded any damaged or discolored samples, and dried the rest at room temperature before grinding them into a powder. Roughly 100 grams of powder was soaked in 400 milliliters of ethanol and shaken for 74 hours in a constant-temperature incubator, after which the mixture was centrifuged, filtered, and evaporated at 50 degrees Celsius to yield a crude extract. One gram of this extract was dissolved in one milliliter of DMSO and diluted into a liter of distilled water for spraying. The choice of DMSO was deliberate: the solvent is powerful enough to carry a complex mixture of plant compounds into solution, and at concentrations below 0.1 percent it is considered safe for plants and animals.

To understand why the extract works, the team turned the crude preparation over to liquid chromatography coupled with high-resolution mass spectrometry. The analysis tentatively identified 21 chemical compounds in the ethanolic extract, five of which stand out as plausible biopesticide agents: apigenin-7-O-glucoside, indole-3-butyric acid, strychnine, phytol, and hexadecanoic acid. Apigenin-7-O-glucoside, a flavonoid, has documented insecticidal effects, killing insects, reducing their egg-laying, deterring feeding and growth, and interfering with their ability to digest plant tissue. Indole-3-butyric acid, better known as a plant growth regulator, has been used alongside other chemicals to boost plant resistance to insect attack. Phytol, a diterpene alcohol, has shown considerable promise as an eco-friendly botanical insecticide, while hexadecanoic acid, a common fatty acid, carries known nematicidal and pesticidal activity.

The presence of strychnine among the identified compounds is notable and, on its face, alarming, since the alkaloid is infamous as a rodenticide and avicide. The authors note that strychnine is also classified as an insecticide, and its detection here was tentative, based on mass-spectrometric matching rather than isolation and quantification. That caveat matters: identifying a compound in a complex plant extract does not establish how much of it is present, whether it is bioavailable to insects, or whether it contributes to the observed pest suppression. It also raises questions that any regulatory pathway would need to answer, since a biopesticide is only as acceptable as its most toxic constituent. The researchers themselves frame the compound list as a set of targets for future work rather than a finished safety profile.

Complementary Fourier transform infrared spectroscopy added a second layer of chemical characterization. The spectra revealed absorption bands consistent with primary aliphatic amines, carboxylic acids, alkanes, alcohols, sulfones, phenols, anhydrides, alkenes, and even a halo compound, painting a picture of an extract rich in the kinds of secondary metabolites that plants deploy as chemical defenses. Such compounds can disrupt insect cell membranes, inactivate enzymes, and derail metabolic processes, leading to growth inhibition or death. Notably, the extract did not appear to harm the crop itself: chlorophyll content measured by SPAD meter, photosynthesis rates, plant spread, and head diameter showed no significant differences among treatments, and extract-treated plants actually grew tallest, though not significantly so.

The broader context gives the work its urgency. Synthetic pesticides remain the backbone of pest control in intensive vegetable production, but chronic exposure has been linked in assessments to cancers, neurological and cardiovascular disease, reproductive harm, and impaired respiratory health, while agricultural chemicals contribute to documented declines in insects, birds, bats, earthworms, fish, and amphibians. Botanical biopesticides, by contrast, tend to be target-specific, sparing natural enemies of pests, and they decompose quickly in the environment, leaving minimal residues on fresh produce. Bottle gourd itself is an apt source: among the first plants ever domesticated and the only crop with a global distribution before Columbus, it is already cultivated worldwide for food and medicine, and earlier studies have shown its leaf extracts effective against cabbage aphids and mosquito larvae.

The Hokkaido team is careful to note the limits of the study. It was a small-scale field trial in a single season at a single site, and the extract’s formulation, concentration, and spray schedule were not optimized. Whether the same results hold across different climates, soil types, and pest pressures remains to be seen, as does the extract’s compatibility with integrated pest management programs and its effects on beneficial insects under real-world conditions. Still, the headline numbers are hard to ignore: a leaf extract from a plant most gardeners grow for its fruit cut looper damage nearly in half in peak weeks and matched a commercial pyrethroid on yield. If follow-up research can pin down the active compounds, standardize the formulation, and clear the safety questions, the ancient bottle gourd may find a new role as a factory for sustainable crop protection.

Subject of Research: Botanical biopesticide control of cabbage looper in cabbage using bottle gourd leaf extract

Article Title: Efficacy of bottle gourd (Lagenaria siceraria) leaf extract in protecting against cabbage looper (Trichoplusia ni) (Lepidoptera: Noctuidae) infestation

Article References: Sultana, M. S., Shimizu, N., Itoh, T., & Iwabuchi, K. (2025). Efficacy of bottle gourd (Lagenaria siceraria) leaf extract in protecting against cabbage looper (Trichoplusia ni) (Lepidoptera: Noctuidae) infestation. Crop Health, 3(1), Article 11. https://doi.org/10.1007/s44297-025-00050-7

Image Credits: AI Generated

DOI: 10.1007/s44297-025-00050-7

Keywords: bottle gourd, cabbage looper, biopesticide, botanical insecticide, Lagenaria siceraria, Trichoplusia ni, cabbage, LC-MS, phytochemicals, sustainable agriculture, permethrin, pest management

The case for alternatives to conventional treatments is pressing. Chemical pesticides, although effective and easy to manufacture, contaminate soil, leach toxic compounds into groundwater and disrupt beneficial microbial communities that naturally suppress pathogens. Copper compounds, a mainstay of orchard sprays, accumulate in the environment, and copper resistance in target bacteria has steadily eroded their value. Antibiotics have fared little better: the global rise of antibiotic resistance and risks to human health have limited agricultural use, and resistance development in phytopathogens undermines long-term efficacy. Concerns extend to pollinators as well, since pesticide exposure and habitat contamination threaten the honeybees on which fruit, nut and oilseed yields depend. Within the European Union, most conventional pesticides and antibiotics are progressively being banned, leaving farmers in urgent need of new tools.

Phages offer an attractive answer because of their exquisite host specificity. They infect and lyse their target bacteria without touching beneficial microorganisms, plants, animals or humans, so applications are not expected to disturb plant or soil microbiota. They also replicate only when sufficient susceptible hosts are present, naturally declining once pathogen populations fall. The team behind the new work built on three virulent phages previously isolated from urban wastewater: ɸEF1 and ɸEF2, which attack E. amylovora, and ɸXF1, which attacks X. campestris. Genomic analysis confirmed that all three follow a strictly lytic cycle, producing transparent plaques and complete host lysis in liquid culture within five to eight hours.

The first task was optimizing infection dynamics. Testing multiplicities of infection (MOI) ranging from 0.01 to 10, the researchers found that higher MOIs offered no significant improvement in pathogen reduction. A MOI of 1 was selected because it produced greater reductions in bacterial density than 0.1 for all three phages. From a manufacturing perspective this matters enormously: low MOIs allow a single concentrated phage stock to be diluted into large-volume formulations, whereas MOIs of 100 or 1000 would require titers of 10^10 to 10^11 plaque-forming units per milliliter, inflating production complexity and cost. Host density also influenced performance, with better bacterial reductions at 10^6 colony-forming units per milliliter than at 10^7. Under the optimized conditions, ɸXF1 delivered the strongest lysis, a 5.5 log10 reduction in host density within four hours, while ɸEF1 and ɸEF2 achieved reductions of 3.5 and 3.8 log10 respectively, with their combined use potentially acting synergistically.

Shelf life was the next hurdle. The phages were stored at 4°C, 20°C and 37°C for six months and enumerated at regular intervals. Both ɸEF1 and ɸEF2 remained stable for the full 180 days at 4°C, with losses close to or below 1 log10 unit, and performed acceptably at 20°C with roughly 2 log10 reductions. At 37°C, however, both declined sharply, falling 8 log10 units by day 150. Phage ɸXF1 was somewhat more fragile, losing about 2 log10 units at 4°C and 3 log10 at 20°C over six months, and becoming undetectable within 28 days at 37°C. Notably, the study is among the first to demonstrate long-term stability of phage formulations at room temperature, a finding with substantial logistical value because it could eliminate the need for costly cold chains or freeze-drying, both of which complicate distribution and can reduce infectious particle counts.

Acidity proved a hard limit. All three phages were inactivated within a single day at pH 3, whereas at neutral and alkaline pH stability rose markedly. ɸEF2 was the sturdiest, losing less than about 1 log10 unit at both pH 7 and pH 9 over six months, while ɸEF1 declined by 1.2 log10 units and ɸXF1 dropped 2.0 log10 at pH 7 and 3.8 log10 at pH 9. These results directly inform formulation choices, since any carrier solution must avoid acidic conditions that would rapidly destroy infectivity before the product even reaches the crop.

The decisive challenge, however, was sunlight. Ultraviolet radiation induces DNA lesions that block phage replication and transcription, and daylight inactivation is widely regarded as the primary obstacle to phage biocontrol in the field. The researchers therefore screened three photoprotective agents already used in agriculture: aminic acid, an acidic protein hydrolysate; Amino 22%, a commercial amino acid-based biostimulant; and Vegepron Sun, a calcium carbonate (CaCO3) foliar fertilizer that forms a reflective film on fruit and leaves. Suspensions were exposed outdoors to full natural sunlight for six hours, with solar irradiance peaking above 700 watts per square meter around midday. Aminic acid failed outright: even after neutralization, phages declined within two hours and became undetectable by four, performing worse than unprotected controls. In contrast, 24 percent CaCO3 kept average reductions to just 0.73 log10 units after six hours, with AA22 providing intermediate protection.

Controlled irradiation under a germicidal 253.7-nanometer UV lamp confirmed the hierarchy. Unprotected phages fell below detection within one hour, but both photoprotectants extended recoverable infectivity to eight hours, and CaCO3 consistently outperformed AA22. With 24 percent CaCO3, all three phages lost only 1.2 to 1.4 log10 units after eight hours of irradiation, compared with 2 to 2.5 log10 at the 12 percent concentration, establishing that the higher formulation offered superior and more consistent shielding. The team then moved to real crop surfaces, inoculating detached pear fruits and cabbage leaves and exposing them to sunlight. Because phage recovery from plant tissue is notoriously inefficient, the group first optimized extraction, finding that homogenization in a 10 percent beef extract solution with a Stomacher blender recovered roughly 76.7 percent of inoculated phages, versus a mere 0.79 percent with phage buffer. On the plants, 24 percent CaCO3 again proved decisive: after six hours of sun exposure, ɸEF1 titers on pears averaged 1.8 log10 units higher with the additive than without, ɸEF2 gained 2.5 log10 units, and ɸXF1 on cabbage leaves showed gains of up to 1.9 log10 units at early time points, while the unprotected suspension dropped below detection within four hours.

The authors argue that these results, combined with the regulatory status of the additives, clear a practical path to commercialization. Because CaCO3 and AA22 are already approved agricultural biostimulants, incorporating them into phage products should face fewer regulatory barriers than novel excipients. Recommended deployment would favor evening spraying to maximize the protective window, with reapplication every five to seven days during high-risk periods or after heavy rainfall, all compatible with Integrated Pest Management frameworks. Only a handful of commercial phage products currently exist for plant disease, including Erwiphage PLUS against fire blight and Biolyse against Xanthomonas in Europe, and Ecofire and AgriPhage elsewhere. By demonstrating room-temperature shelf stability, defined infection parameters and sunlight-protected persistence on crops, the study provides concrete formulation guidance for expanding that market, in line with European Green Deal goals for residue-free food. The researchers caution that greenhouse experiments and multi-season field trials remain necessary to validate efficacy across diverse climates, but the blueprint for a viable phage biopesticide now looks considerably more complete.

Subject of Research: Design of a bacteriophage-based biocontrol product against the fire blight pathogen Erwinia amylovora and the black rot pathogen Xanthomonas campestris

Article Title: Design of a Bacteriophage‐Based Product for Biocontrol of Fire Blight and Black Rot

Article References: Vique, G., Blanco‐Picazo, P., Trenchs, A., Ramos‐Barbero, M. D., Isern, M., Quirós, P., Atares, S., Salaet, I., Sala‐Comorera, L., Rodríguez‐Rubio, L., & Muniesa, M. (2026). Design of a Bacteriophage‐Based Product for Biocontrol of Fire Blight and Black Rot. Microbial Biotechnology, 19(9), Article e70436. https://doi.org/10.1111/1751-7915.70436

Image Credits: AI Generated

DOI: 10.1111/1751-7915.70436

Keywords: bacteriophage, biocontrol, fire blight, black rot, Erwinia amylovora, Xanthomonas campestris, calcium carbonate, UV photoprotection, plant pathology, biopesticide, phage stability, sustainable agriculture