2020 Compensation Capacity of High and Low Vigor Cotton Plants in Response to Pre-Flower Injury by Tarnished Plant Bug (Heteroptera: Miridae)

Agricultural Experiment Station for support of this work. David Wildy and Justin Wildy also are acknowledged for their support. Crop tolerance of feeding injury by tarnished plant bug (Lygus lineolaris Palisot de Beauvois) (Heteroptera: Miridae) was investigated in field trials conducted in a highly variable field in Northeast Arkansas in 2005 and 2006. Plant biomass assessments were used to classify crop areas of high and low plant vigor. In a split plot design, field plots were positioned across these variable plant types with main plot irrigated and non irrigated blocks. Insect induced injury was manipulated by augmenting natural field populations of plant bugs with lab reared nymphs and by application of insecticides. Crop response was measured using the COTMAN crop monitoring system and in end-of-season plant mapping as well as in measures of lint yield and fiber quality. First position square retention varied from 98 % down to 71 % at first flowers across treatments; total no. of main stem sympodia ranged from 3.4 up to 10 nodes per plant in non-irrigated low vigor plants and irrigated, high vigor plants. Irrigation significantly affected yield and fiber quality in 2005, but insect induced injury was not a limiting factor. Greater levels of injury were observed with high vigor plants, but that injury failed to significantly reduce yield. In 2006. irrigation did not affect lint yield, but insect feeding did result in economic damage in plants in the low vigor classification. Managers considering site specific approaches for insect control should consider variability in compensation capacity and tolerance for pest injury when planning adjustments in action thresholds