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Single and multiple in-season measurements as indicators of at-harvest cotton boll damage caused by verde plant bug (Hemiptera: Miridae)
- Michael J. Brewer, J. Scott Armstrong, Roy D. Parker
- Journal of economic entomology 2013 v.106 no.D pp. 1310-1316
- cotton, Creontiades, insect pests, linear models, Gossypium hirsutum, crop damage, bolls, Texas
- The ability to monitor verde plant bug, Creontiades signatus Distant (Hemiptera: Miridae), and the progression of cotton, Gossypium hirsutum L., boll responses to feeding and associated cotton boll rot development provided opportunity to assess if a single in-season measurement had value in evaluating subsequent at-harvest damage to bolls and if multiple in-season measurements enhanced their combined use. One in-season verde plant bug density measurement, three in-season plant injury measurements, and two at-harvest damage measurements were taken in 15 cotton fields of the coastal cotton growing region of south Texas, 2010. Linear regression selected two measurements as potentially useful indicators of at-harvest damage: verde plant bug density at mid-bloom (adjusted r2 = 0.68, P = 0.0004) and internal boll injury of the carpel wall two weeks later (adjusted r2 = 0.72, P = 0.004). Considering use of multiple measurements, a stepwise multiple regression of the four in-season measurements selected a univariate model (verde plant bug density) using a 0.15 selection criterion (adjusted r2 = 0.74, P = 0.0002) and a bivariate model (verde plant bug density—internal boll injury) using a 0.25 selection criterion (adjusted r2 = 0.76, P = 0.0007) as acceptable indicators of at harvest damage. In a field validation using cultivar and water regime treatments experiencing low verde plant bug pressure in 2011 and 2012, the bivariate model performed better than models using verde plant bug density or internal boll injury separately. This case of verde plant bug damaging cotton bolls exemplified the benefits of using multiple in-season measurements under the challenging situation when at-harvest damage results from a sequence of plant responses initiated by in-season insect feeding.