Interactions betweenBactra verutanaand the Development of Purple Nutsedge(Cyperus rotundus)Grown Under Three Temperature Regimes

Abstract

For effective biological control through augmentation,Bactra verutanaZeller, would have to be released against purple nutsedge(Cyperus rotundusL.) in May and June when temperatures are cooler than they are from late July through September when maximal natural populations of this biological control agent occur.Bactralarvae exposed to simulated mid-May (24/13 C) and mid-June (29/18 C) temperature regimes developed more slowly than larvae exposed to the mid-July (32/26 C) temperature regime, but nutsedge plant growth was also slower. Thus, the relative amounts of feeding injury were similar at all three regimes. Larval feeding generally increased the number of shoots slightly, but not significantly, reduced significantly the production of inflorescences, and reduced the weight of total dry matter produced between 28 and 49%.