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Field experiments were conducted during 2020-21 to evaluate different biorational insecticides and entomopathogenic nematodes against ash weevil, Myllocerus subfasciatus Guerin-Meneville. The results revealed that the IPM Module 3 [comprised of soil application of Metarhizium anisopliae @ 5 kg/ha followed by soil drenching with EPN Heterorhabditis indica @ 20 kg/ha at 30 DAT and foliar spray with M. anisopliae @ 5kg/ha at 45 DAT] was found superior with the lowest number of M. subfasciatus adults per plant (mean ± SE) (2.06 ± 0.07) and the lowest leaf damage (4.35 ± 0.59 per leaf per plant), followed by the IPM Module 2 [comprised soil application of neem cake followed by application of entomopathogenic nematode H. indica @ 20 kg/ha at 30 DAT and foliar application of B. bassiana @ 5 kg/ha at 45 DAT] which was also found significant in reducing the number of M. subfasciatus and leaf damage by ash weevil (2.30 ± 0.15; 4.85 ± 0.69 respectively), compared to untreated check (2.91 ± 0.13, 5.63 ± 0.34 respectively). [ABSTRACT FROM AUTHOR]

Abstract The potato tuber moth (PTM), Phthorimaea operculella, is one of the most economically important potato pests worldwide. In the present study, the potential of Steinernema carpocapsae for controlling PTM in infested potato tubers was evaluated and compared with S. feltiae and the pyrethroid alpha-cypermethrin. The results for efficacy percentage showed that S.carpocapsae [72.52 and 65.49% for 12.6 × 106 and 6.2 × 106 infective juveniles (IJs), respectively] and S. feltiae (69.56% for 12.6 × 106 IJs) were as efficient as alpha-cypermethrin (66.76% for10 mg ai L−1). Both concentrations of alpha-cypermethrin and S. carpocapsae showed the least tuber damage with no significant differences (33.5–39.33%), while it was as high as the control (59.26%) in both concentrations of S. feltiae. The median lethal concentration (LC50) value for S. carpocapsae [5.46 (4.41–6.55) IJs per prepupa] was significantly lower than S. feltiae [8.52 (7.12-10.20) IJs per prepupa] which confirms the superiority of S. carpocapsae. These promising findings introduce S. carpocapsae as a part of the potato tuber protection programs for treating the tubers. Accordingly, EPNs can be considered as an appropriate alternative to synthetic chemicals for PTM control. [ABSTRACT FROM AUTHOR]

Many vector mosquito species have evolved resistance to chemical insecticides and the search for novel biological control strategies warrants further attention. Entomopathogenic nematodes (EPNs) (Heterorhabditis and Steinernema spp.) have been developed as biological control agents for use against agricultural pests but whether they could be used to control aquatic mosquito larvae warrants further research. We exposed Aedes aegypti and Ochlerotatus detritus larvae to commercially available (Steinernema feltiae, S. carpocapsae, S. kraussei and Heterorhabditis bacteriophora) and wild isolated (S. affine and S. glaseri) EPNs and monitored survival over 7 days. We also exposed EPNs to water with a range of salinities and pHs found in the marshland habitats of British mosquitoes. Ae. aegypti and O. detritus were killed by commercial EPNs, but wild strains were unable to kill Ae. aegypti yet did kill O. detritus. All EPNs were capable of tolerating a wide range of pHs but showed variable tolerance to different salinities. EPNs could be used as an alternative to chemical insecticides but target species and habitat may influence choice of EPN strain in control operations. [ABSTRACT FROM AUTHOR]

Chironomidae, or non-biting midges, are found worldwide in a wide variety of aquatic habitats. During periods of mass adult eclosion they can become a nuisance and health hazard. Current control methods target the aquatic larval stage and include the use of insect growth regulators or insecticides, which may be prohibited in certain environments or affect non-target organisms. The aim of this study was to investigate whether entomopathogenic nematodes (EPNs) of the families Steinernematidae and Heterorhabditidae, currently employed for control of terrestrial crop pests, could be used as a viable biocontrol for the aquatic larval stages of the Chrionomidae, offering an alternative to current chemical methods. We demonstrate that Steinernema feltiae (Filipjev, 1934), Steinernema carpocapsae (Weiser, 1955), Steinernema kraussei (Steiner, 1923) and Heterorhabditis bacteriophora (Poinar, 1975) are able to survive in water up to 96 h and are able to parasitize and kill Chironomus plumosus (Linnaeus, 1758) larvae, with mortality observed after just 24 h exposure and with < 20% survival after 4 days. We also show that following application to the water column, EPNs sink to the bottom of the lentic water body and can remain alive for more than 96 h. Taken together, we believe that several EPN species could be developed as a valid form of biocontrol for Chironomidae. [ABSTRACT FROM AUTHOR]

This paper presents an improved way of applying Monte Carlo simulation using the crossentropy method to calculate the risk of capacity deficit of a composite power system. By applying importance sampling for load states in addition to the generation and transmission states in a systematic manner, the proposed method is many orders of magnitude more efficient than the crude Monte Carlo simulation and considerably more efficient than other crossentropy-based algorithms that apply other ways of estimating the importance sampling distributions. An effective performance metric of system states is applied in order to find optimal importance sampling distributions during presimulation that significantly reduces the required computational effort. Simulations, using well-known IEEE reliability test systems, show that even problems that are nearly intractable using crude Monte Carlo simulation become very manageable using the proposed method. [ABSTRACT FROM AUTHOR]