Sampling Optimization and Crop Interface Effects on Populations in Southeastern USA Cotton.

Tarnished plant bug, (Hemiptera: Miridae), is an economically damaging pest in cotton production systems across the southern United States. We systematically scouted 120 commercial cotton fields across five southeastern states during susceptible growth stages in 2019 and 2020 to investigate sampling optimization and the effect of interface crop and landscape composition on abundance. Variance component analysis determined field and within-field spatial scales, compared with agricultural district and state, accounted for more variation in density using sweep net and drop cloth sampling. This result highlights the importance of field-level scouting efforts. Using within-field samples, a fixed-precision sampling plan determined 8 and 23 sampling units were needed to determine population estimates with 0.25 precision for sweep net (100 sweeps per unit) and drop cloth (1.5 row-m per unit) sampling, respectively. A spatial Bayesian hierarchical model was developed to determine local landscape (<0.5 km from field edges) effects on in cotton. The proportion of agricultural area and double-crop wheat and soybeans were positively associated with density, and fields with more contiguous cotton areas negatively predicted populations. These results will improve monitoring programs and treatment management decisions in southeastern USA cotton.