Increasing ecological heterogeneity can constrain biopesticide resistance evolution

Ecological safety of insecticide based on entomopathogenic virus DsCPV-1 for nontarget invertebrates

For the first time under laboratory conditions, the virulence of a unique cypovirus strain, DsCPV-1, which has broad host specificity, was tested on nontarget aquatic organisms (natural species: Gammarus lacustris, Anopheles messeae, Coenagrion lunulatum, Cloeon robusta, Chironomus sp., Ilyocoris cimicoides, and Plea minutissima; laboratory species: Aedes aegypti and Daphnia magna), a terrestrial pollinator species (Apis mellifera), and an entomophage (Podisus maculiventris). The probability of this virus's accumulation in the bodies of invertebrates and of its transmission along a trophic chain was evaluated by two approaches: bioassays and a molecular diagnostic analysis. In the bioassays, there was no significant increase in mortality among all the tested aquatic and terrestrial nontarget species exposed to DsCPV-1 as compared with control groups (no virus). When we fed Podisus maculiventris with caterpillars having active DsCPV-1 infection (i.e., with the virus replicating in the host) no viral replication was observed in bug. No replication was also observed in mosquitos as well as in bee after viral treatment. Thus, the results show that the DsCPV-1 virus has excellent environmental safety toward many invertebrate species and can be recommended for the control of lepidopteran pests in forestry and agriculture as insecticide with light effect on environment.

Persistence of widespread moderate Spinosad resistance among wild melon fly (Zeugodacus cucurbitae) and oriental fruit fly (Bactrocera dorsalis) populations on the major Hawaiian islands

BACKGROUND

Insecticide resistance among invasive tephritid fruit flies poses a great risk to national food security and has the potential to disrupt quarantine and eradication programs, which rely on the efficacy of Spinosad to prevent widespread establishment in North America. During 2022 to 2023 we surveyed the extent of Spinosad resistance of two key species, oriental fruit fly Bactrocera dorsalis, and melon fly Zeugodacus cucurbitae, from 20 sites across five Hawaiian Islands including Kaua'i, O'ahu, Maui, Molokai and the "Big Island" (Hawai'i).

RESULTS

We used topical thoracic applications of eight concentrations of Spinosad ranging from 0.028 to 3.6 mg/mL to evaluate the lethal concentration (LC50 and LC99) required to kill wild-caught males. Resistance ratios (RR) were calculated by comparing the LC50 of wild flies to laboratory susceptible lines maintained in colony. Our results identified at least two new sites of concern for melon fly resistance on the Big Island, and at least four sites of concern for oriental fruit fly, all of which were located on the Big Island. At these locations RRs were >5. On O'ahu, melon fly RRs were >10.

CONCLUSIONS

The persistence of Spinosad resistance is concerning, yet it is a reduction compared to the values reported previously and before changes to Spinosad use recommendations by local extension agents beginning in 2017. For oriental fruit fly, these RR values are the highest levels that have been detected in wild Hawai'i populations. These data suggest that expanded Spinosad reduction and replacement programs are warranted given the ongoing issues with Spinosad resistance in Hawai'i and expansion in the number of species affected. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

resevol: An R package for spatially explicit models of pesticide resistance given evolving pest genomes

The evolution of pesticide resistance is a widespread problem with potentially severe consequences for global food security. We introduce the resevol R package, which simulates individual-based models of pests with evolving genomes that produce complex, polygenic, and covarying traits affecting pest life history and pesticide resistance. Simulations are modelled on a spatially-explicit and highly customisable landscape in which crop and pesticide application and rotation can vary, making the package a highly flexible tool for both general and tactical models of pest management and resistance evolution. We present the key features of the resevol package and demonstrate its use for a simple example simulating pests with two covarying traits. The resevol R package is open source under GNU Public License. All source code and documentation are available on GitHub.

Solid-State Fermentation: Applications and Future Perspectives for Biostimulant and Biopesticides Production

With the expansion of the green products market and the worldwide policies and strategies directed toward a green revolution and ecological transition, the demand for innovative approaches is always on the rise. Among the sustainable agricultural approaches, microbial-based products are emerging over time as effective and feasible alternatives to agrochemicals. However, the production, formulation, and commercialization of some products can be challenging. Among the main challenges are the industrial production processes that ensure the quality of the product and its cost on the market. In the context of a circular economy, solid-state fermentation (SSF) might represent a smart approach to obtaining valuable products from waste and by-products. SSF enables the growth of various microorganisms on solid surfaces in the absence or near absence of free-flowing water. It is a valuable and practical method and is used in the food, pharmaceutical, energy, and chemical industries. Nevertheless, the application of this technology in the production of formulations useful in agriculture is still limited. This review summarizes the literature dealing with SSF agricultural applications and the future perspective of its use in sustainable agriculture. The survey showed good potential for SSF to produce biostimulants and biopesticides useful in agriculture.