Entomopathogenic fungi are important biological control agents and represent sustainable alternatives to chemical insecticides. Among them, Metarhizium pingshaense (Hypocreales: Clavicipitaceae) has shown strong insecticidal potential against a range of agricultural pests. However, host innate immunity is one of several factors that can strongly constrain the success of fungal infection. The insect Ectropis grisescens (Lepidoptera: Geometridae), a major defoliator in tea plantations, is primarily managed with chemical insecticides and resistance to these biocides has become an increasing concern, highlighting the need to optimize fungal-based control strategies. In this study, we isolated a M. pingshaense strain (Mp237) from infected E. grisescens cadavers and investigated the roles of key Toll pathway components (Tube, Pelle, and Dorsal) in antifungal defense. The Toll pathway is a highly conserved innate immune signaling pathway in insects. Fungal challenge significantly induced the expression of these genes, particularly in immune-related tissues. RNA interference-mediated silencing of Tube, Pelle, or Dorsal, reduced antimicrobial peptide expression and significantly increased larval susceptibility to M. pingshaense infection. Collectively, our findings demonstrate that Toll signaling is indispensable for antifungal immunity in E. grisescens and provides a mechanistic framework for enhancing the efficacy of M. pingshaense–based biocontrol against this economically important tea pest.
The invasive fire ant Solenopsis invicta (Hymenoptera: Formicidae) is a major pest that causes extensive ecological damage. In this study we assessed the pathogenic potential of the entomopathogenic fungus Metarhizium anisopliae (Hypocreales: Clavicipitaceae) CQMa421 strain against this pest and identified molecular targets that could be exploited in control strategies. Our results show that M. anisopliae effectively kills S. invicta, with a median lethal time (LT50) of 5.46 days. To understand the host response to infection, we performed RNA‑sequencing at 12 and 24 h post-infection. More than 10,000 genes were detected across both time points. Differential expression analysis identified 123 genes (20 up-regulated, 103 down-regulated) at 12 h and 241 genes (164 upregulated, 77 down-regulated) at 24 h. The number of up-regulated genes increased over time. Enrichment analysis of the differentially expressed genes highlighted several key pathways, including G‑protein‑coupled receptor signaling, exopeptidase activity, metabolic processes, and Wnt signaling. By focusing on four major biological processes, metabolism, immunity, development and behavior, we identified a set of candidate genes that may serve as critical targets during fungal infection. Collectively, these findings support the potential of M. anisopliae as a biocontrol agent against S. invicta, and the identified host candidate genes provide a molecular foundation for the development of improved management strategies.
Efficient laboratory rearing and behavioral optimization of natural enemies are essential for advancing biological control programs. This study evaluated how rearing standardization influence the reproductive output of the earwig Doru luteipes (Scudder) (Dermaptera: Forficulidae), an important generalist predator in agroecosystems. We investigated the effects of clutch density per container, sex ratio, and oviposition shelter availability on reproductive output. Increasing clutch density did not affect embryonic duration, hatching rate, or partial egg cannibalism. However, single-clutch containers showed lower total cannibalism and higher early nymph survival. While maintaining the same number of oviposition shelters, increasing the number of females per rearing container resulted in higher offspring production, despite temporal variability in oviposition patterns. Collectively, these findings demonstrate that rearing design plays a critical role in improving the performance and scalability of D. luteipes production. The results provide practical guidelines for laboratory and mass-rearing protocols and highlight the importance of prey identity in shaping predator reproductive success, contributing to the broader application of earwigs in sustainable pest management strategies.
Most biological control programmes against invasive alien plants (weeds) utilise agents collected from indigenous populations of the target weed that are thought to have a long coevolution history between the target weed and the agent. These biocontrol agents are referred to as old associations. There are, however, several examples of cactus weeds being successfully controlled by new associations, which are agents collected on other cactus species rather than the target weed itself and are thought to lack any significant coevolutionary history with the target weed. It is therefore unclear whether new or old associations are more effective biocontrol agents for invasive alien Cactaceae. This study aimed to evaluate whether old or new associations of Dactylopius tomentosus Lamarck (Hemiptera: Dactylopiidae) are more effective biocontrol agents for invasive Cylindropuntia (Cactaceae) species. Three lineages of D. tomentosus were tested on seven Cylindropuntia species. The fitness of each lineage was assessed using adult survival, female body mass, and a fitness index, with phylogenetic distance between the primary host plant and closely related species used as a predictor. The results showed a significant negative correlation between fitness and phylogenetic distance across all lineages, with the highest survival, body mass, and fitness index on the primary host and its closest relatives. These findings support the use of old associations as biocontrol agents for Cylindropuntia species, and for invasive alien plants in general.
Sclerotinia sclerotiorum (Lib.) de Bary is a devastating phytopathogen responsible for significant yield losses across a wide range of crops. Sustainable management strategies, including microbial agents and plant-derived essential oils, have gained increasing attention. However, their combined application remains largely underexplored. In this study, we evaluated the combined efficacy of Pseudomonas protegens CS11 and selected essential oil priming for the suppression of S. sclerotiorum. Among three essential oils tested (lemongrass, tea tree, and lavender), CS11 showed strong tolerance to lemongrass oil. In vitro assays demonstrated that lemongrass oil significantly inhibited the mycelial growth of S. sclerotiorum. In plant-based assays, lemongrass oil did not adversely affect tomato seedling growth and enhanced chlorophyll content. Greenhouse experiments further revealed that combined priming prior to S. sclerotiorum challenge reduced disease severity compared with unprimed controls and lemongrass oil-primed plants, and improved plant height and leaf number compared to CS11- and lemongrass oil-primed plants. This enhanced protection accompanied by maintained plant growth and development was associated with strong early disease suppression by direct inhibition of S. sclerotiorum, increased activities of defence enzymes and the upregulation of genes associated with salicylic and jasmonic acid pathways. This study demonstrates that the combined application of CS11 and lemongrass oil provides an integrated strategy that maintains strong suppression of S. sclerotiorum while promoting plant growth and modulating defence responses.
