Prevalence of sporadic insect pests of seedling corn and factors affecting risk of infestation

Authors: Sappington, Thomas; Hesler, Louis; Allen, Clint; Luttrell, Randall; Schneider, Sharon

Submitted to: Journal of Integrated Pest Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/2017
Publication Date: 6/15/2018
Citation: Sappington, T.W., Hesler, L.S., Allen, K.C., Luttrell, R.G., Papiernik, S.K. 2018. Prevalence of sporadic insect pests of seedling corn and factors affecting risk of infestation. Journal of Integrated Pest Management. 9(1):16. https://doi.org/10.1093/jipm/pmx020.
DOI: https://doi.org/10.1093/jipm/pmx020

Interpretive Summary: Most corn planted in the U.S. is protected proactively from a number of early season insect pests by treating the seed with a neonicotinoid insecticide. These early season pests are considered sporadic or minor, but can occasionally cause severe damage to seedlings. Many are difficult or impossible to scout, or have no viable rescue treatment available by the time a problem is detected. While insecticidal seed treatments can help reduce risk from these pests, they are applied without knowledge of pest presence, and there are growing concerns about negative environmental effects of neonicotinoid use. In this study, ARS researchers assembled what is known about risk factors associated with infestations by the pests specifically targeted by neonicotinoid seed treatments. It is clear that most of these pests will exert little or no pressure in most fields most of the time. However, certain circumstances can increase risk of an economic infestation by any particular sporadic/minor pest. Such risk factors commonly differ depending on region, agronomic practices, soil type, drainage, weather, and many other factors. The findings will be of use to farmers, agricultural consultants, university extension specialists, industry scientists, and regulatory agencies in understanding the economic risks and benefits of neonicotinoid seed treatments under specific conditions at the farm level.

Technical Abstract: A prophylactic insecticide treatment is a tactic compatible with an IPM strategy for a particular pest only when a rescue treatment is not a realistic option, and if there is a reasonable expectation of economic injury by that pest. Most corn planted in the U.S. is protected from several sporadic early-season pests by neonicotinoid seed treatments, usually without knowledge of the threat posed in a given field. We undertook an extensive literature review of these sporadic pests to clarify the prevalence of economic infestations in different regions of the U.S., and the agronomic, biotic, and abiotic factors that affect the likelihood of attack. The summaries of prevalence and risk factors presented here should help farmers and consultants better assess the value of prophylactic protection of seedling corn under the conditions at hand, and provide others with a better understanding of the complex issues involved at the farmer's level. The profiles suggest that, in general, pressure from most of these sporadic pests on seedling corn is rare, local, or seldom high enough to negatively affect yield. However, this is not true in all regions of the country for all sporadic pests. An important issue exposed by the profiles is that the value of prophylactic protection of seedling corn depends on understanding the likely combined pressure from multiple species. While such risk may often still be negligible, there is a great need for robust methodology to assess the risk posed by multiple pests. This represents a significant challenge for future research.