Invasions of green mirid (Creontiades dilutus) (Stål) (Hemiptera: Miridae) into cotton – perceptions of Australian crop consultants

Abstract

Green mirids, Creontiades dilutus (Stål) (Hemiptera, Miridae), are primary pests of cotton (Gossypium hirsutum) (Malvaceae) in eastern Australia. Severe infestations delay crop development and reduce yield through boll drop (fruit loss). Most cotton farmers employ crop consultants to monitor mirids and recommend pest management options. Effective pest management needs to account for both increased pest numbers within cotton (i.e. the production of mirid offspring), and the movement of mirids into crops (invasions). The objective of this study is to evaluate what is known about environmental processes that influence mirid invasions by assessing records on mirid infestations spanning the 1976/77 through 2015/16 cotton seasons. The primary records of mirid invasion are qualitative surveys conducted in 1993 and 2014 that asked consultants about their monitoring efforts. These qualitative surveys are supplemented by seasonal reports of pest pressures across eastern Australia, and sporadic field surveys that quantified mirid densities. Although each consultant monitored only a small portion of the overall agricultural landscape, there was agreement that the earliest seasonal mirid invasions were associated with squaring (flower bud forming) cotton, and were influenced by nearby vegetation. There was, however, substantial variation in the responses regarding local factors that may influence mirid invasions. The importance of distinguishing between mirid invasions and the production of offspring within cotton is discussed. Methods are proposed that would improve the spatial and temporal resolution of mirid monitoring efforts across the agricultural landscape.