ABSTRACT Spodoptera frugiperda (J. E. Smith), an invasive pest, poses a major threat to agricultural productivity and food security in China. This study evaluated the biological control potential of the native parasitic wasp Meteorus pulchricornis (Wesmael) against third-instar S. frugiperda larvae. We examined the developmental dynamics of M. pulchricornis under different temperatures, its functional response to varying host densities, lifetime parasitism capacity, and larval morphological characteristics. Results showed that increasing temperature accelerated development but reduced emergence rates, with optimal performance at 26 °C. Functional response analysis indicated a Type II model, with parasitism escalating as host density increases before reaching saturation. Adults exhibited a continuous parasitism period of up to 22 days and parasitised an average of 131 hosts throughout their lifespan. Semi-field trials further confirmed its capacity to suppress S. frugiperda populations, achieving a 90.8% larval reduction and 52.0% corrected control efficacy, with parasitism and cocoon formation rates of 60.4% and 54.2%, respectively. Collectively, this study provides the first comprehensive evaluation of the development, parasitic capacity, and field efficacy of M. pulchricornis against S. frugiperda in China, offering crucial insights for its application in integrated pest management.

ABSTRACT Telenomus remus Nixon is being explored as a candidate for managing the fall armyworm, Spodoptera frugiperda (J.E. Smith), in biocontrol approaches. However, its utilisation in augmentative/inundative releases requires large numbers that are difficult to produce. Cold storage of either the host's eggs or pupae of T. remus has emerged as a viable method to facilitate large-scale production in synchronised field releases. This research investigates the impacts of storage at 9°C on S. frugiperda eggs and T. remus pupae at varying durations. Findings indicated that while T. remus can parasitise stored S. frugiperda eggs, the parasitism rate significantly declined between 1.66 to 6.53 times after periods of 7 to 14 days compared to freshly parasitised eggs. Notably, successful parasitism dropped to 27% after 14 days of storage of eggs at 9°C, and no parasitism was recorded after 21 and 28 days. Moreover, storing S. frugiperda host eggs at 9°C does not impair the parasitism abilities of subsequent T. remus generations. At the same time, its pupae (8 days after parasitisation) can remain viable for up to 7 days storage at 9°C without adverse effects.

ABSTRACT The biocontrol potential of the green lacewing, Chrysoperla zastrowi sillemi (Esben-Peterson) against greenhouse whitefly (GHWF), Trialeurodes vaporariorum (Westwood), was evaluated in the laboratory at 27 ± 2°C, 65 ± 5% RH, and a 16L:8D photoperiod. All larval stages of C. z. sillemi prey on all nymphal instars of GHWF; however, the third instar proved to be the most effective, consuming 349.50, 351.3, 328.9, and 486.4 first, second, third and fourth instars of GHWF nymphs. The total larval duration on various whitefly instars ranged from 9 to 10 days. The mean number of nymphs consumed per day during the whole larval period ranged from 33.52 to 44.05 nymphs, with the highest consumption by the third instar larva. Among different nymphal instars of T. vaporariorum, the predation on first and second instars was significantly higher, by the first instar predator, and on third and fourth instar whitefly nymphs, respectively, by the third instar predator. The first instar C. z. sillemi larvae demonstrated a preference for first (28.78%) and second instar whitefly nymphs (34.67%), whereas the third instar larvae exhibited a preference for third (88.40%) and fourth instar (89.60%) whitefly nymphs. Further, C. z. sillemi exhibited type-II functional response to whitefly nymphs. The third instar larvae of C. z. sillemi had the highest attack rate (0.168) and maximum predation rate (177.926) compared to younger instars. As a result of our findings, the predator C. z. sillemi can be maintained in the laboratory and has the potential to be developed as an efficient biocontrol agent against T. vaporariorum.

ABSTRACT Fusarium culmorum is the main pathogen causing head blight (FHB) in Algeria and in several parts of the world. The aim of this study is to evaluate the effect of Trichoderma combined with wheat cultivars, on disease index, grain weight and yield. Two assays were conducted in field trials for two seasons, with two antagonistic strains, T. atroviride (Ta13) and T. longibrachiatum (TL9) against two mycotoxigenic F. culmorum strains (BD11) and (FC7). Methods of seed treatment before sowing and head treatment during anthesis were investigated on three durum wheat genotypes (cv. Vitron) and two lines (G03 and G01). Trichoderma treated seed before sowing induced 28.16% and 26.88% of disease reduction caused by BD11 combining Ta13–G01 and Ta13–Vitron respectively, and 24.61% of disease reduction caused by FC7 combining TL9–Vitron. Ear treatment leaded to 19.56% and 35.94% of DI reduction caused by BD11 combining Ta13–G01 and TL9–Vitron, respectively. TGW was increased with the combination of Ta13–G01 and Ta13–Vitron by about 17% with ear treatment against BD11. Ear treatment against BD11 increased yield by about 150%, 97% and 22%, 30% using Ta13–Vitron, Ta13–G03, Ta13–G01 and TL9–Vitron, respectively, and with 29% by TL9–G03 once against FC7. Yield obtained with treated seed showed an increase by 114% and 58% with Ta13–Vitron and Ta13–G03, respectively. However, a decrease by 25% with combination TL9–G01–FC7 and by 35% with TL9–G03–BD11 were noted. Our results show that the bioefficacy of the antagonist is genotype dependant, and that the relationship antagonist–cultivar–pathogen is complex, variable over time and depends on many biotic and abiotic factors.

ABSTRACT Spiders are common generalist predators in agroecosystems, contributing to natural pest control through diverse trophic interactions. However, their trophic role depends on how individual traits influence prey selection and network structure. Using standardised transect walks, direct observation, and prey collection from webs, we investigated individual-based trophic networks of the orb-weaving spider Neoscona oaxacensis (Keyserling, 1864) (Araneae: Araneidae) in maize fields in Mexico, focusing on the influence of body size and web position on trophic structure. Spiders consumed a wide range of prey spanning nine orders and 65 taxa, with Coleoptera and Orthoptera dominating the diet. Notably, N. oaxacensis frequently preyed on Sphenarium purpurascens Charpentier, 1842 (Orthoptera: Pyrgomorphidae), a major maize pest, highlighting its potential agricultural importance. The interaction networks were sparsely connected, highly modular, and lacked nestedness, suggesting heterogeneous prey use among individuals, with groups of spiders focusing on small subsets of prey. Larger spiders had higher betweenness centrality, acting as more central nodes in the metaweb; whereas web height was linked to dietary specialisation, spiders from higher strata preyed upon fewer species, yet these prey were commonly shared across individuals, indicating a generalist feeding pattern. Overall, N. oaxacensis exhibited marked individual trophic heterogeneity, driven by morphological and spatial traits. The combination of low network connectivity, strong modularity, and trait-dependent prey use suggests that individual differentiation probably enhances the stability and functional resilience of trophic networks in agricultural landscapes.

ABSTRACT Fusarium wilt is a devastating plant disease that causes significant yield losses worldwide. Biocontrol agents represent a sustainable alternative for Fusarium wilt management. In this study, three rhizospheric bacterial strains from Rhizobium and Bacillus genera were evaluated for managing Fusarium wilt in chili plants. Rhizobium nepotum strain Z-21 isolated from the rhizosphere of Vicia faba significantly reduced Fusarium wilt severity, showing a disease index of 26.2% that was 67.9% lower than the pathogen alone treatment. Additionally, Z-21 significantly increased shoot length (62.93%), root length (136.16%), and dry biomass (42.42%), compared to the negative control. We elucidated metabolomic mechanisms underlying Z-21-induced systemic resistance in chili plants. Z-21 increased total phenolic compounds by 37.54% and enhanced activities of peroxidase and polyphenol oxidase enzymes by 2.12-fold and 1.78-fold, respectively, compared to the pathogen control. Ultra-performance liquid chromatography tandem triple quadrupole mass spectrometry (UPLC-QQQ-ESI-MS) revealed that strain Z-21 effectively altered the metabolomic profile of chili plants. The application of Z-21 significantly increased the levels of numerous metabolites in chili plants that were reduced by Fusarium wilt infection. Metabolites present in the culture filtrates of Z-21 were identified by GC/MS analysis and used as ligands in molecular docking analysis. In-silico molecular docking analysis showed that di-2-ethylhexyl phthalate (DEHP) and 2,2'-methylenebis-6-t-butyl-4-methylphenol (MBBM) had the highest docking scores towards defence-related receptor kinase proteins. To our knowledge, this is the first report of Rhizobium nepotum as a biocontrol agent against Fusarium wilt in chili through induced systemic resistance (ISR).

ABSTRACT Introducing exotic insects for classical biological control of weeds carries risks, necessitating rigorous testing to ensure candidate agents pose little threat to non-target species. However, host testing methods can overestimate the likelihood of damage to non-target plants under field conditions. Consequently, effective, host-specific biocontrol agents can be unnecessarily denied permission for release. In assessing the host range of two weevil species as candidate biocontrol agents for the aquatic weed, Sagittaria platyphylla (Engelm.) J.G.Sm. (Alismataceae) we designed native range surveys and laboratory host tests, focusing on closely related species present in both contexts. This allowed us to relate host testing results to field host use of a fruit-feeding weevil, Listronotus appendiculatus LeConte (Coleoptera: Curculionidae) and a crown-boring weevil, L. sordidus Gyllenhal. We used molecular barcoding of endogenous larvae to identify distinct Listronotus taxa associated with each sampled host plant species in the North American native range. In laboratory tests, both Listronotus species could oviposit and develop to adults on several Alismataceae genera in addition to Sagittaria. Field surveys revealed a clear distinction between the Listronotus taxa associated with Sagittaria and those sampled from Echinodorus, indicating that L. appendiculatus and L. sordidus don’t utilise Echinodorus in the field. Field surveys found that laboratory host testing overestimated the host range of these candidate biocontrol agents. We used this information to recommend experimental approaches to better assess the host range of the candidate biocontrol agents.

ABSTRACT Soybean (Glycine max L.) is a leading crop occupying more than one million hectares in Uruguay. Seedlings are affected by fungal diseases and soil-dwelling insects, which together reduce emergence by 15–40%. Accordingly, seed treatments rely on fungicides and insecticides that affect the viability of Bradyrhizobium elkanii inoculants, reducing biological nitrogen fixation and leaving environmental residues. Entomopathogenic Metarhizium spp. infect insects and antagonise phytopathogens, promoting plant performance. Native Metarhizium isolates were screened in vitro and in planta for compatibility with commercial B. elkanii strains U1301 and U1302, and against Fusarium graminearum, Pythium sylvaticum, Pythium ultimum and Rhizoctonia oryzae. Although several isolates caused inhibition around rhizobial colonies in vitro, seed-coating trials showed no impairment of nodulation or shoot biomass, which confirms compatibility. Metarhizium robertsii ILB167 and ILB440 persisted epiphytically (102–103 CFU/g); but no endophytic colonisation was detected. Dual-culture assays identified M. robertsii ILB167 and ILB440 as the most effective inhibitors, reducing phytopathogen growth to 53%. These isolates, together with M. brunneum ILB429, produced the widest inhibition halos, indicating diffusible antifungal metabolites. In naturally infested soil, the M. robertsii isolates increased seed germination by more than 10%. Under controlled pathogen pressure, M. robertsii ILB440 improved seedling emergence in the presence of F. graminearum and R. oryzae, whereas no isolate alleviated Pythium spp. losses. Solid-substrate fermentation on rice grains yielded up to 17.2 × 108 conidia/g for M. robertsii ILB440. Collectively, M. robertsii ILB440 is a robust candidate for integrated seed coatings combining biocontrol, rhizobial compatibility and scalable production, aligning with Uruguay’s National Plan for Bioinputs.

ABSTRACT Tamarisk leaf beetles (Diorhabda carinulata Desbrochers) were introduced as a biological control agent for invasive Tamarix shrubs by USDA-APHIS in the early 2000s and have spread more rapidly than predicted. Previous research has not explored beetle dispersal to isolated Tamarix stands. Here, we used glue traps to capture beetles travelling toward and away from a small, isolated Tamarix stand across several seasons. We found that most beetles were captured moving from the direction of stands of Tamarix up to 6 km away. Densities of beetles at the target corresponded with frequency of wind from the direction of the source stands, speed of wind, and density of beetles at the closest possible source, 3.6 km away. To our knowledge, this is the first clear evidence of long-distance wind dispersal by this species, which has implications for both management of the invasive Tamarix and an endangered bird that nests in it.

ABSTRACT Delairea odorata, an ornamental vine from South Africa, is a significant environmental weed, and a target for biological control, in Australia. The leaf – and stem-mining moth Digitivalva delaireae is a highly damaging candidate agent. Following extensive host-specificity testing by the USA, we conducted additional trials in Australia and South Africa, to assess the moth’s prospects for introduction into Australia. During trials with 33 non-target species, representing the closet relatives, only D. odorata supported larval feeding damage and development to pupation. Our results confirm that D. delaireae is highly host specific and thus a promising candidate for Australia.