The annual bluegrass weevil (ABW) (Listronotus maculicollis Kirby) is a key pest of short-mown golf course turf that preferentially oviposits and achieves greater larval densities on annual bluegrass (Poa annua L.), which is less tolerant of ABW feeding than creeping bentgrass (Agrostis stolonifera L.). Poa annua is also a persistent weed. Thus, withholding ABW-targeting insecticides can allow ABW to function as a biological control agent by selectively suppressing P. annua in mixed stands. However, higher P. annua abundance may increase ABW damage and reduce stand-level tolerance, leading to unacceptable turfgrass injury in highly managed fine turf and limiting its utility for biological control. We tested whether initial P. annua cover constrains this strategy. Two field experiments were conducted in mixed creeping bentgrass-P. annua fairway turf. Plots representing initial P. annua cover levels (0, 10, 25, and 50%) were managed under preventive, damage-threshold, or no-insecticide programs; threshold applications were triggered when turfgrass quality fell below 6 on a 1–9 scale. Withholding or delaying insecticide applications reduced P. annua cover relative to preventive programs (typically 20–50% relative reduction) but caused short-lived declines in turfgrass quality during peak ABW damage. Unacceptable turfgrass quality, when it occurred, was generally limited to 1–3 weeks and was primarily observed in plots with realized initial P. annua cover of 37% or greater, whereas plots with 33% cover or less generally maintained acceptable quality. Collectively, these findings suggest that ABW can be leveraged as a conditional biological control agent in mixed stands with relatively low P. annua abundance, highlighting opportunities to integrate weed and insect management while reducing insecticide use.
Cashew is a commercially significant plantation crop grown extensively along the western and eastern coastal regions of India. In July 2023, an unusual outbreak of leaf blight was observed in cashew nurseries located at Dakshina Kannada, Karnataka, India, coinciding with the onset of the southwest monsoon and prolonged high relative humidity (RH) with an incidence of 30-35%. The symptomatic disease samples were collected for the suspected pathogen isolation, and subsequent cultural and micromorphological studies identified the pathogen belonging to the genus Beltrania. Further, molecular barcoding of nrITS (PV639794) and nrLSU (PV643879) region sequencing, followed by phylogenetic analysis, conclusively identified the species as Beltrania rhombica. Further, pathogenicity tests were conducted on healthy seedlings, the typical disease symptoms developed 10-12 days after inoculation (DAI). The identification of the pathogen was established based on morphological and cultural features after re-isolation. This study confirms the first report of Beltrania rhombica as a causal agent of leaf blight in cashew as evidence based on Koch's postulates, marking its expansion to a new host. These findings are very useful for developing effective management practices and provides baseline pathogen data for future epidemiological investigations of the important emerging pathogen in cashew.
Roselle (Hibiscus sabdariffa L.), recognized for its diuretic and mild laxative effects, is increasingly utilized in herbal medicine, natural foods, and as a colorant. Wilt and root rot disease pose a major economic threat to roselle, with 90% economic losses. Fusarium proliferatum was identified as the causal agent of roselle wilt, with three representative fungal isolates (FHS1, FHS2, and FHS3) obtained from infected root samples. On potato dextrose agar, F. proliferatum colonies grew rapidly, covering the entire petri dish within seven days at 28°C, with pinkish-white pigmentation and darker tones on the reverse. Phylogenetic analyses using maximum-likelihood methods on combined sequences from the Internal Transcribed Spacer (ITS), translation elongation factor 1-α (EF-1α), and RPB2 genes confirmed the pathogen’s identity. Symptoms appeared fifteen days post-inoculation, and the pathogen was successfully re-isolated, fulfilling Koch’s postulates. Pathogenicity of roselle genotypes revealed that DHS 5 had the highest Disease Index (93.33%), whereas DHS 3, DHS 6, DHS 9, and DHS 11 showed moderate indices (40–50%), and DHS 12, DHS 13, and DHS 15 exhibited low indices (5-20%). To the best of our knowledge, this study is the first report of Fusarium proliferatum causing wilt and root rot disease of roselle (Hibiscus sabdariffa L.) in India.
Hibiscus cannabinus L. (Malvales: Malvaceae) is an important leafy vegetable crop in peri-urban agriculture, contributing to household income and poverty reduction in Burkina Faso. However, during storage, kenaf seeds are heavily damaged by Spermophagus niger (Coleoptera: Chrysomelidae), leading to substantial losses. Managing this pest mainly depends on synthetic insecticides, which requires the need for sustainable and environmentally friendly alternatives. The present study aimed to evaluate the relative susceptibility levels of ten H. cannabinus accessions from three provinces in Burkina Faso against S. niger attacks. Experiments were conducted under laboratory conditions, assessing seed morphological parameters and biodemographic parameters of S. niger on each accession. The results showed that seeds from the different accessions varied significantly in weight and diameter. These morphological differences did not significant influence S. niger development, which was able to complete its life cycle on all ten accessions. According to Dobie's classification, accessions NAD2, NAD4, KOG4, NAT4, NAG1, KOK3, and KAM4 were highly susceptible to S. niger, whereas accessions NAG2, KOW3, and KOZ3 were classified as susceptible. Accession KOZ3 appears to be the least favorable for S. niger development, as indicated by a low number of emerged insects (18), a longer development time (31.3 ± 0.66 days), reduced body weight of emerged individuals, and a low intrinsic rate of population increase (0.0822 ± 0.0118). These results provide preliminary information useful for future breeding programs and the development of integrated pest management strategies targeting S. niger, with accession KOZ3 representing a particularly promising candidate for further investigation.
The fall armyworm, Spodoptera frugiperda (J.E. Smith), is a highly polyphagous invasive pest, causing serious yield losses in maize and rice since invading China. To develop effective integrated pest management (IPM) strategies, the in vitro compatibility and combined toxicity of the entomopathogenic fungus Metarhizium rileyi (Farl.) with five chitin synthesis inhibitors (CSIs) against third-instar larvae of S. frugiperda were investigated. Results showed that chlorfluazuron, lufenuron, and chlorbenzuron did not affect fungal mycelial growth, sporulation, or conidial germination, indicating high compatibility. In contrast, hexaflumuron and pyriproxyfen significantly inhibited fungal development, reducing conidial production by 40–84% and germination by 35–69% in a dose-dependent manner. Bioassays revealed that M. rileyi at 10,000 mg/L caused 73.9% corrected mortality by day 6 (LC50 = 328.6 mg/L), while lufenuron, chlorfluazuron, and chlorbenzuron exhibited strong lethality, with 6-day LC50 values of 11.2, 13.7, and 92.6 mg/L, respectively. When combined at their respective 6-day LC50 values in a 1:1 volume ratio, only the M. rileyi–lufenuron combination exceeded the expected additive mortality, indicating synergistic potential. Further co-toxicity coefficient (CTC) analysis indicated a synergistic interaction (CTC > 120) when the lufenuron proportion exceeded 0.42%, reaching a maximum CTC of 1,943 at 0.86% lufenuron. This combination accelerated mortality onset by 24 h compared with M. rileyi alone and significantly increased corrected mortality on day 4 (P < 0.05), and achieved near-complete mortality by day 6. In conclusion, the 99: 1 (M. rileyi: lufenuron) combination demonstrated synergistic activity under laboratory conditions, and this ratio warrants further formulation development and field evaluation.
Flavescence dorée (FD) is a yellows disease that causes serious damage in European vineyards. The phytoplasma associated with FD is transmitted mainly by the leafhopper Scaphoideus titanus. Monitoring S. titanus populations is essential for defining the optimal timing of insecticide applications and evaluating the efficacy of control strategies. In the territory of the Consortium Conegliano Valdobbiadene Prosecco Superiore DOCG (northeastern Italy), where severe FD outbreaks were recorded since 2019, S. titanus populations were monitored from 2021 to 2024. During the same years, the spatial and temporal distribution of S. titanus populations was analyzed in four fragmented and critical areas. In 2022, the appearance of first instar nymphs was earlier than in other years, due to higher spring temperatures. Adult population densities have decreased since 2022, due to the effectiveness of pyrethroids used against nymphs. Nymph population densities significantly declined from 2023 onwards. In the four fragmented areas, significant patches and gaps of nymph and adult populations were recorded, with significant aggregations detected in 10 out of 16 analyzed periods in Area 1 and in 8 out of 16 in Area 3. In 2021 and 2022, when chemical control of S. titanus was not really effective, significant associations between nymph and adult spatial distributions were observed in three out of four areas. The distribution of nymphs in early spring, before insecticide application, was significantly associated with that of adults in the late summer of the previous year in three areas in 2022, two areas in 2023 and one area in 2024. In Area 1, nymph and adult patches persisted for two consecutive growing seasons, resulting no longer present only after the application of effective chemical control strategies in all vineyards of this area. For this reason, an area-wide approach to FD management is crucial, as a few infested vineyards can nullify the efforts made in well-managed vineyards.
In Central and South America, stored beans are heavily affected by Zabrotes subfasciatus (Boh.) (Coleoptera: Chrysomelidae), a major pest responsible for significant post-harvest losses. The widespread use of synthetic insecticides for its control raises concerns regarding human health and environmental safety, highlighting the need for sustainable alternatives. This study evaluated the chemical composition and bioactivity of essential oils (EOs) from Dysphania ambrosioides (DA-EO), Pelargonium graveolens (PG-EO), and Piper callosum (PC-EO) against Zabrotes subfasciatus. Chemical analyses by GC-FID and GC-MS revealed that the major compounds were cis-ascaridole (29.9%) in DA-EO, citronellol (22.3%) in PG-EO, and (Z)-isosafrole (46.9%) in PC-EO. The EOs exhibited insecticidal activity through fumigation, topical application, and residual contact in a concentration dependent manner. PC-EO and PG-EO significantly reduced oviposition and adult emergence. In addition, all EOs affected the walking behavior of adults, indicating behavioral disruption. DA-EO showed the highest bioactivity, with LC50 values of 3.75 μL L−1 of air (fumigation) and 48.35 μL L−1 (residual contact), and an LD50 of 6.81 μL mg−1 (topical application), demonstrating strong insecticidal activity. These findings support the potential of essential oils as eco-friendly alternatives for the management of Zabrotes subfasciatus in stored grains.
Foliar application of bacterial biocontrol agents in soybean (Glycine max) has traditionally focused on pathogen control, frequently neglecting multifunctional advantages. This study investigated the multifunctionality of a Bacillus velezensis-based product within an integrated disease management, evaluating its efficacy on foliar disease control and possible enhancements in grain yield, seed quality, and the induction of transgenerational defense and growth. Field experiments conducted over two growing seasons compared traditional chemical management of soybean foliar diseases to integrated managements with bioproducts. On each season, it was evaluated foliar sprays with a B. velezensis-based product as a stand-alone treatment or combined with fungicides and/or Trichoderma-based product. All treatments significantly reduced major foliar disease severities (Asian rust by 32–54%, downy mildew by 75%, powdery mildew by 67%, brown spot by 32–60%), decreasing defoliation and increasing yield by 22%. Treatments with B. velezensis increased protein (10%) and lipid content (6%), while reducing seed-borne pathogens, compared to the control. Notably, progeny assays revealed a transgenerational conditioning effect: the F1 progeny of B. velezensis-treated plants exhibited significantly greater biomass, higher chlorophyll levels, and increased defense enzyme activity (superoxide dismutase and peroxidase) when challenged with Macrophomina phaseolina, despite the absence of treatments in progenies. These findings offer a new paradigm for sustainable soybean production by redefining B. velezensis foliar application from a narrow focus on plant protection against foliar pathogens toward a broader perspective of a multifunctional bioproduct capable of improving nutritional content in harvested seed and driving transgenerational benefits indicating a long-term crop resilience.
Sweet corn yield formation is highly sensitive to biotic stress during specific growth stages. However, quantitative evidence linking fall armyworm (FAW; Spodoptera frugiperda [J. E. Smith]) infestation intensity, crop phenology, insecticide input intensity, and marketable yield response remains limited under tropical conditions. Here, we evaluated sweet corn yield loss and farmgate income responses to FAW infestation across key growth stages under different insecticide input levels in Hainan, China. Field experiments first compared the efficacy of four commonly used insecticides (chlorfenapyr, spinetoram, chlorantraniliprole, and cyantraniliprole) against FAW infestation to identify an effective reference insecticide, after which multi-frequency application trials were conducted to quantify yield loss and net farmgate income responses under different application frequencies and timings.Results showed that yield loss declined with increasing insecticide input, however, yield gains plateaued beyond moderate application levels, resulting in diminishing marginal returns in net farm income. Controlled cage experiments revealed strong growth stage–dependent yield sensitivity of sweet corn to FAW infestation, with early vegetative (V4–V6) and reproductive (VT–R1) stages as periods of high crop sensitivity, with greater yield losses per unit pest infestation than mid-vegetative stages. Across the 2021 and 2022 seasons, corresponding economic thresholds (ETs) ranged from 7.77–13.10 larvae per 100 plants at V4–V6, increased to 17.47–33.25 and 24.89–46.52 at mid-vegetative stages (V8–V10 and V12–V14), and declined to 12.44–21.78 at VT–R1. By linking stage-specific yield response functions with input intensity and economic outcomes, this study demonstrates that sweet corn yield and income responses to FAW infestation are strongly growth stage dependent. Aligning insecticide input intensity with stage-specific crop sensitivity, rather than pest presence alone, provides a quantitative basis for improving yield stability and economic performance in tropical sweet corn production systems while avoiding unnecessary chemical inputs.
Pomegranate is an important fruit crop greatly appreciated for its nutritional and nutraceutical properties. However, anthracnose, a major post-harvest disease, threatens pomegranate production worldwide, including Mauritius. In January 2025, pomegranate fruits exhibiting typical anthracnose symptoms were collected from Flacq, Pamplemousses, and Triolet. Both isolates PG1 and PG2 produced white to light grey colonies with dense aerial mycelium. Molecular identification based on the internal transcribed spacer (ITS), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and beta-tubulin (TUB2) gene sequences, followed by a phylogenetic inference, identified the isolate as Colletotrichum theobromicola. Pathogenicity of both isolates was confirmed by inoculating healthy, non-wounded pomegranate fruits, with the re-isolation of the original fungal strains, thus fulfilling Koch's postulates. This is the first report of C. theobromicola causing anthracnose of pomegranate in Mauritius, highlighting the need for further research on effective disease control strategies.
Stem rot, caused by Sclerotium oryzae, is a common and important disease of rice grown in California. This study used 19 stem rot fungicide trials conducted between 2017 and 2024 in the Sacramento Valley of California to determine the relationship between disease incidence and severity. Eighteen of these trials were used to estimate the impact of stem rot severity on grain yield and seven to evaluate the best timing of application for the azoxystrobin containing fungicides Quadris and QuiltXcel. Results show that incidence and severity are related and that incidence (expressed as proportion) up to values of 0.9 can predict the severity of stem rot up to a severity index value of 2. Yield loss due to stem rot severity was found to be described best by a linear model including yield level as a factor, with a rate of yield loss of 258 kg/ha (95% CI: 193 to 325 kg/ha) for each unit change in stem rot severity index. Relative yield loss per unit increase in severity index was calculated to be 2.63% (95% CI: 1.95 to 3.3%). The azoxystrobin containing fungicides Quadris and QuiltXcel reduced stem rot severity when applied at the boot stage but not at tillering. Application of Quadris at boot or QuiltXcel at heading resulted in significant yield increases.
The sterile insect technique (SIT) is an environmentally friendly and sustainable area-wide pest suppression strategy that involves mass-rearing of target insects, sterilising them through ionising radiation, and releasing them into target sites. Upon release, sterile males mate with wild females, resulting in the production of non-viable eggs and a subsequent population decline. This review examines the historical development, successes, challenges, and future prospects for SIT in managing key agricultural pests in Africa. In Africa, SIT was first implemented in Tunisia during the 1970s to control the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), and subsequent programmes have targeted six other pest species across South Africa, Morocco, and Mauritius. Despite some positive results, most SIT initiatives have been terminated due to technical, logistical, or financial challenges. Currently, several programmes remain in developmental or pilot phases. Key factors influencing the success of SIT in Africa include financial constraints, regulatory frameworks, beneficiary buy-in, and species-specific radiosensitivity. Leveraging recent advances in biotechnology, automation, and genetic tools may enhance the effectiveness and scalability of SIT programmes against agricultural pests across Africa.
Mythimna separata (Oriental armyworm) is a serious defoliating pest of maize, and host plant resistance (HPR) offers a sustainable approach for its management. The present study evaluated 18 maize genotypes for resistance to M. separata by integrating Leaf Damage Rating (LDR), oviposition preference (antixenosis), and leaf morphological traits. Leaf damage was observed at 7, 14, and 21 Days After Infestation (DAI), and the extent of damage differed significantly among genotypes at each stage of observation. Based on Tukey's HSD multiple comparison test, the genotypes CML-208-BBB, LM-12, CML-556, CML-338, DMR-E−63, and HKI-484-5 consistently exhibited low leaf damage ratings (overall mean LDR < 4.0) and were classified as resistant to M. separata. In contrast, DQL-784-4-1, KDM-895-A, V-351, DML-134-2, CML-351, CML-139, and KML-225 showed higher LDR values, with overall means ranging from 6.22 to 8.20, and these genotypes were classified as susceptible to M. separata. Ovipositional preference, assessed under no-choice and multi-choice conditions, showed significant differences in the number of egg batches and the number of eggs in egg masses, with resistant genotypes receiving fewer egg batches and fewer eggs in egg masses, suggesting a strong antixenotic effect. Plant morphological trait analysis revealed significant differences among genotypes in leaf length, leaf width, leaf thickness, plant height, number of nodes, and trichome density. Furthermore, Pearson correlation analysis revealed a strong positive association between LDR and plant morphological traits, including leaf length, leaf width, number of nodes, and plant height. In contrast, leaf thickness and trichome density showed a significantly strong negative correlation with LDR. Principal Component Analysis (PCA) further supported the distinct separation of resistant and susceptible maize genotypes based on LDR and its associated morphological characteristics. Overall, the findings demonstrate that resistance to M. separata in maize is governed by a combination of antixenosis, antibiosis, and plant morphological characteristics rather than a single factor, and identify promising resistant genotypes for use in resistance varieties breeding and integrated pest management programs.
