Costs of <I>Lygus</I> Herbivory on Cotton Associated With Farmer Decision-Making: An Ecoinformatics Approach

Abstract

Because the farmer is typically excluded from the experimental research setting, experimental research may face challenges in evaluating pest management tactics whose costs and benefits hinge on farmer decision-making. In these cases an ecoinformatics approach, in which observational data collected from the commercial farming setting are "mined" to quantify both biological variables and farmer behavior, can complement experimentation as a useful research tool. Here I analyze such an observational data set to characterize associations between early- (June) and mid-season (July) Lygus hesperus Knight populations and farmer decisions to apply plant growth regulators and defoliants. Previous experimental work suggested the hypothesis that Lygus herbivory, by inducing abscission of young flower buds, might generate increased use of plant growth regulators and defoliants. Cotton's ability to compensate for loss of flower buds may, however, increase as plants grow. On upland cotton, June Lygus populations were associated with increased use of plant growth regulators, as expected, but this relationship was not observed for July Lygus populations. June Lygus populations were not associated with the use of defoliants, whereas, surprisingly, July Lygus populations were associated with decreases in defoliant use. In contrast to these positive and negative associations observed on upland cotton, on Pima cotton Lygus populations exhibited no associations with use of either plant growth regulators or defoliants. These results suggest that cotton responses to Lygus herbivory, as demonstrated in previously published experimental studies, can translate into economically meaningful changes in farmer decisions to apply agricultural chemicals.

Ecoinformatics Can Reveal Yield Gaps Associated with Crop-Pest Interactions: A Proof-of-Concept

“…The plant growth regulator mepiquat chloride is used by farmers to shift the plant’s resource allocations from vegetative to reproductive growth, which may enhance yield [ 24 ]. Because L. hesperus herbivory can trigger increased use of mepiquat chloride [ 25 ], we obtained data on mepiquat chloride from consultants.…”

“…), we explored a model that included the numbers of pesticide applications targeting each of these herbivores. Finally, because L. hesperus herbivory may change plant growth form, eliciting changes in farmer decisions to apply plant growth regulators (mepiquat chloride) or defoliants, each of which may influence yield [ 25 ], we explored a model including the number of these applications.…”

Spatiotemporal variation in the relationship between landscape simplification and insecticide use

“…Ecoinformatics approaches, taking advantage of longitudinal data at large spatial scales, can provide unique insight into complex agricultural pest dynamics (Rosenheim 2013). To the extent farmers modify treatment above or below baseline (or manufacturer recommended) applications in response to pest damage, insecticide use data reflect insect pest risk.…”