Status of insecticide resistance and management strategies of Lygus lineolaris in the mid-South
1USDA-ARS, SIMRU, Stoneville, MS, USA
2Department of Entomology and Plant Pathology, Mississippi State University, Starkville, MS, USA
Correspondence: jeffrey.gore@ars.usda.gov
Multiple experiments were conducted on cotton in Mississippi to investigate management of insecticide resistant tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois) (Heteroptera: Miridae). Experiments that controlled native vegetation during the early spring with a single herbicide application reduced tarnished plant bug numbers in cotton (P<0.05) and increased economic returns (P<0.05) for growers in the herbicide treated areas. Another experiment demonstrated the benefits of planting an early season cotton variety (Deltapine 444 BR) versus a later season cotton variety (Deltapine 555 BR). Deltapine 444 BR reached cutout ten days earlier than Deltapine 555 BR and required two fewer foliar applications with insecticides for tarnished plant bugs. Several insecticide screening studies showed that foliar control with currently registered insecticides ranged from 17 to 71 percent control and control with experimental insecticides ranged from 34 to 57 percent control. In an experiment investigating application intervals, plant bug control approached 100 percent when two applications were made four or five days apart and was significantly (P<0.05) better than when the applications were made six (70 percent) and seven (20 percent) days apart, respectively. Rotation with alternative chemistries was shown to improve control of tarnished plant bugs compared to multiple applications with organophosphates. Plots treated with two applications of Orthene (0.5 lb ai/A) five days apart reached threshold significantly (P<0.05) earlier than plots treated with Orthene (0.5 lb ai/A) followed by Centric (2 oz./A). Spray coverage was shown to significantly influence plant bug control. Tarnished plant bug control was significantly higher on okra-leaf cotton than on normal leaf cotton and with hollow cone nozzles than with air induction nozzles. Aldicarb (Temik 15G, Bayer Crop Sciences), applied as a side dress at first flower, reduced plant bug numbers for up to 20 days. Based on these experiments, no one method will provide adequate control of resistant tarnished plant bugs in flowering cotton including foliar insecticides. Therefore, growers and consultants will need to consider alternative strategies integrated with foliar applications to prevent economic losses from tarnished plant bugs.
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