Evaluation of Standardized Bait Trapping Approaches and Climatic Factors That Influence Wireworm Catch in the Canadian Prairies

Abstract

Wireworms are significant pests of a variety of economically important crops grown in the Canadian Prairies. These soil-dwelling larvae of click beetles feed on and burrow into the accessible underground plant tissues, which can result in cosmetic injury, stunting, wilting, and plant death. Successful management of wireworms relies on accurate estimations of their abundance and activity in infested fields. Bait trapping is the most commonly used method for sampling wireworms and standardized approaches have been developed; however, little work has been done to optimize trapping efficacy in different geographical regions. In this study, we evaluated the effect of bait trapping duration, seed formulation, and the causal relationship with CO2 production and soil temperature on the wireworm catch in three fields located in Manitoba, Canada. As expected, wireworm catch increased with trapping duration and placing traps in ground for 8 d is adequate in most cases. Both barley and wheat were more effective baits than soybean; however, barley released more CO2 (i.e., an attractant for wireworms) and performed better at elevated soil temperatures. Overall, the results of this study will serve as valuable guidelines to improve current wireworm sampling methods, and can be integrated into strategies aimed at managing these important pests to crop production.

Seasonal turnover and insights into the overwintering biology of wireworms (Coleoptera: Elateridae) in the Canadian Prairies

“…Consistent with recent wireworm surveillance studies within our geographical region, 26,27 three of the fields were largely composed of H. bicolor and to a lesser extent H. abbreviatus . Both Hypnoidus species are known to co‐occur in Prairie fields, 20,27 and showed a fairly even distribution throughout the season until becoming largely absent by mid‐ to late August, when environmental conditions became unfavorable (cold and wet).…”

“…Soil temperature has been strongly associated with wireworm activity in different geographical locations 20–23,51,52 . To understand why L. californicus larvae require longer than Hypnoidus species to become active subsequent to overwintering, we first performed a series of CCR assays.…”

“…abbreviatus. Both Hypnoidus species are known to co-occur in Prairie fields, 20,27 and showed a fairly even distribution throughout the season until becoming largely absent by mid-to late August, when environmental conditions became unfavorable (cold and wet).…”

“…However, a major limitation of bait trapping is the associated wireworm catch is more a reflection of larval feeding activity during the trapping period and may not directly correlate with the actual wireworm densities in a given field. [18][19][20] A variety of agroenvironmental factors are known to impact larval activity, including soil temperature [20][21][22][23] and soil moisture. 20,[22][23][24][25] Consequently, a pest species present in a field may not be captured in bait traps or their abundance may be underestimated if the environmental conditions in the spring are not optimal for the larvae to engage in feeding behaviors.…”

“…[18][19][20] A variety of agroenvironmental factors are known to impact larval activity, including soil temperature [20][21][22][23] and soil moisture. 20,[22][23][24][25] Consequently, a pest species present in a field may not be captured in bait traps or their abundance may be underestimated if the environmental conditions in the spring are not optimal for the larvae to engage in feeding behaviors.…”