Sublethal exposure, insecticide resistance, and community stress

BACKGROUND Soybean aphid, Aphis glycines, is an invasive insect in North America, considered one of the most important pests of soybean. Their management relies heavily on foliar insecticides, but there is growing effort to expand these tools to include aphid‐resistant varieties. We explored if the LC50 and LC25 of lambda‐cyhalothrin varied between virulent (resistant to Aphis glycines (Rag) soybeans) and avirulent (susceptible to Rag‐genes soybeans) populations of soybean aphid with a leaf‐dip bioassay. We also investigated the response to the LC25 of lambda‐cyhalothrin on adults (F0) and their progeny (F1) for both avirulent and virulent soybean aphid. RESULTS The LC50 of the virulent aphid population was significantly higher compared with the LC50 of the avirulent population. The LC25 significantly reduced fecundity of the F0 generation of avirulent soybean aphid, but no significant effect was observed for virulent aphids. In addition, the LC25 significantly shortened the adult pre‐oviposition period (APOP) and lengthened the total pre‐oviposition period (TPOP) of avirulent aphids, while the mean generation time (T) was significantly increased. For the virulent aphid, sublethal exposure significantly lengthened development time of first and third instars, TPOP, and adult longevity. In addition, all demographic parameters of virulent soybean aphid were significantly affected when they were exposed to the LC25 of lambda‐cyhalothrin. CONCLUSION Our results demonstrate lambda‐cyhalothrin is less toxic to virulent aphids and exposure to the LC25 can trigger hormesis, which may have implications for the long‐term management of this pest with this insecticide as well as with aphid‐resistant varieties of soybean. © 2019 Society of Chemical Industry

Section: Discussionmentioning

confidence: 99%

“…A sublethal concentration of an insecticide can induce hormesis in insects, a biphasic response phenomenon where a low dose of an insecticide may have a stimulatory effect on population parameters, while a high dose leads to inhibition . These sublethal effects can favor pest resurgence and the development of insecticide resistance …”

Section: Introductionmentioning

confidence: 99%

Soybean aphid (Hemiptera: Aphididae) response to lambda‐cyhalothrin varies with its virulence status to aphid‐resistant soybean

Valmorbida

Muraro

Hodgson

et al. 2019

“…Therefore, the relatively high levels of carbofuran resistance observed in the tuber moth are the result of inadvertent selection, as also reported among maize weevils and whiteflies . Regardless, such inadvertent selection is a pest management concern, and particularly so among pests of vegetable crops (e.g. Biondi et al …”

Section: Discussionmentioning

confidence: 91%

Trade‐off and adaptive cost in a multiple‐resistant strain of the invasive potato tuber moth Tecia solanivora

Gutiérrez

Bacca

Zambrano

et al. 2019

BACKGROUND Resistance to pesticides is an evolutionary process that entails, in most cases, substantial consequences to the biology of the resistant populations. In this study we focus on the life history traits of the potato tuber moth Tecia solanivora, an invasive and voracious pest for which resistance to pyrethroid insecticides was recently reported. Marginally resistant and multiple‐resistant populations were selected from eight sampled localities in Colombia; the use of a fully susceptible population was not possible since none was recognized in the laboratory or field. The multiple‐resistant Siachoque population exhibited a 42‐fold resistance to the carbamate insecticide carbofuran, and low levels of resistance to chlorpyrifos, a trend observed in six of the eight tested populations. This population also exhibits 24‐fold resistance to permethrin. The marginally resistant population of Gualmatán showed 4‐fold resistance to chlorpyrifos. RESULTS The multiple‐resistant population exhibited a 3.8‐day shorter developmental time than the susceptible population, but with higher larval mortality. The peak of egg‐laying was delayed in the resistant population in 9 days and the population growth rate was lower than that of the susceptible population. CONCLUSION We hypothesize that the short developmental time of the multiple‐resistant population may be an adaptation to minimize exposure to insecticides, which are applied to the soil. This adaptation is likely to require the surviving adults to compensate for the smaller nutrient amounts accumulated by the larvae in investing part of its adult life in securing the necessary resources for late‐life egg production. © 2018 Society of Chemical Industry

“…Sublethal pesticide exposure can interfere with individual physiology, causing changes in behaviour because of either toxic or non‐toxic responses associated with such exposure . Thus, we were expecting the acaricides to interfere with passive dispersal of N. baraki, as the dispersal requires a particular set of behaviours leading to a posture able to maximize the effectiveness of taking off on the wind .…”

Section: Discussionmentioning

confidence: 99%

“…Declining habitat suitability is an important trigger of dispersal, including reduction of food sources, and changes in temperature and humidity conditions, among others . Management tactics also potentially compromise habitat suitability, favouring dispersal from the contaminated habitat, a typical condition‐dependent decision, although pesticide use may also shift species dominance and prevailing population phenotypes . Curiously, the potential impact of pesticides on the dispersal of targeted and non‐targeted species remains largely unrecognized, with even less recognition of passive dispersal.…”

Section: Introductionmentioning

confidence: 99%

Pesticides and passive dispersal: acaricide‐ and starvation‐induced take‐off of the predatory mite Neoseiulus baraki

Monteiro

Silva

Lima

et al. 2018