Does Drought Increase the Risk of Insects Developing Behavioral Resistance to Systemic Insecticides?

Abstract

Increases in severity and frequency of drought periods, average global temperatures, and more erratic fluctuations in rainfall patterns due to climate change are predicted to have a dramatic impact on agricultural production systems. Insect pest populations in agricultural and horticultural systems are also expected to be impacted, both in terms of their spatial and temporal distributions and in their status as pest species. In this opinion-based article, we discuss how indirect effects of drought may adversely affect the performance of systemic insecticides and also lead to increased risk of insect pests developing behavioral insecticide resistance. We hypothesize that more pronounced drought will decrease uptake and increase the magnitude of nonuniform translocation of systemic insecticides within treated crop plants, and that may have two concurrent consequences: 1) reduced pesticide performance, and 2) increased likelihood of insect pests evolving behavioral insecticide resistance. Under this scenario, pests that can sense and avoid acquisition of lethal dosages of systemic insecticides within crop plants will have a selective advantage. This may lead to selection for insect behavioral avoidance, so that insects predominantly feed and oviposit on portions of crop plants with low concentration of systemic insecticide. Limited research has been published on the effect of environmental variables, including drought, on pesticide performance, but we present and discuss studies that support the hypothesis described above. In addition, we wish to highlight the importance of studying the many ways environmental factors can affect, directly and indirectly, both the performance of insecticides and the risk of target insect pests developing resistance.

Climate contributes to the evolution of pesticide resistance

“…Climate can influence the evolution of resistance by affecting the generation time of multivoltine pests (Tobin, Nagarkatti, Loeb, & Saunders, 2008), with shorter generation times expected to speed up the rate of resistance evolution. Climatic conditions can also influence selection pressures on resistance alleles by influencing the rate of breakdown of chemicals in the environment (Khodaverdi, Fowles, Bick, & Nansen, 2016), increasing selection when cross-resistance occurs between chemicals and climatic extremes (Patil, Lole, & Deobagkar, 1996), and increasing the susceptibility of organisms to chemicals when they are exposed to climatically stressful conditions (Polson, Brogdon, Rawlins, & Chadee, 2012).…”

An Interactive Teaching Tool Describing Resistance Evolution and Basic Economics of Insecticide-Based Pest Management

“…Based purely on genetics, a given insecticide may be expected to kill 100% of homozygous susceptible individuals. However, some survival of these insect pest individuals could be attributed to factors accounting for low and incomplete spray coverage of contact insecticides [31,32] and/or sublethal and non-uniform concentration of systemic insecticides in portions of crop canopies [33]. In this theoretical scenario, the total pest population reaches 80% of carrying capacity after about 11 generations, and this coincides with the resistance allele frequency reaching 50%.…”

Phone App to Perform Quality Control of Pesticide Spray Applications in Field Crops

“…Finally, there are reasons to be concerned about possible links between low and inconsistent insecticide spray coverage and the long-term risk of physiological resistance evolution in target pest populations of insects, weeds, and other pests [17][18][19][20]. Inconsistent and low spray coverage is of particular concern when contact insecticides are applied, but it may also be of relevance to the long-term performance of systemic and translaminar insecticides [21].…”