Area-wide management of the tarnished plant bug by reduction ofearly-season wild host plant density

摘要

An experiment was conducted in Sunflower and Washington Counties in the Delta of Mississippi in 1998 that evaluated control of tarnished plant bugs (TPB), Lygus lineolaris (Palisot de Beauvois), in cotton, Gossypium hirsutum L., by reduction in numbers of wild host plants found near fields with herbicides in April. Four experimental areas (three check areas and one treated area) each approximately square and 4.8 km on a side were used. Marginal areas at least 100 m in length around ditches, fields, and roads with good stands of wild hosts in all four experimental areas were chosen for treatment and/or sampling. Wild host plant densities in the sample areas in the four experimental areas were not significantly different in pre-treatment counts. Treatment of the sample areas with a combination of mecoprop + 2, 4-D + dicamba at 1.55 + 0.54 + 0.17 kg AI/ha significantly reduced host plant density as compared to host plant density in the check areas. TPB populations on wild hosts in the sample areas were numerically higher in the treated area than they were in the three check areas prior to application of the herbicides. TPB populations in the treated sample areas declined 4.1-fold as compared to TPB populations found in the sample areas in the three check areas, when sampled 2-3 weeks after treatment. Small areas with good stands of plant hosts were also spot-treated with glyphosate, but these areas were not sampled. In the treated experimental area, an estimated 28.7 ha of marginal areas with wild host plants were present, and 7.9 ha (27.5%) were treated with the two herbicides. Cotton fields were sampled weekly in the treated area (14 fields) and three check areas (33 fields) for TPB from the 2nd week in June through the Ist week of August. TPB numbers found in the cotton were very low and no effect on TPB numbers found in cotton in the treated area could be detected.