Matthew T. Williams

Selected insecticide treatments were evaluated for control of tarnished and clouded plant bugs in cotton at the West Tennessee Research and Education Center at Jackson, TN. Cotton was planted on 9 May 2017. The test was arranged in an RCB design with four replicates. Individual plots were 12.67 × 35 ft and planted at a rate of four seeds per row foot on 38-inch row spacing. Treatments were applied with a high clearance sprayer calibrated to deliver 9.2 GPA at 40 PSI with 8001 flat fan nozzles. The first application was made 20 Jul (Appl A) to flowering cotton when plant bugs exceeded the economic threshold of six plant bugs per 10 row ft. A second application was made (31 Jul, Appl B) as populations in all treatments again exceeded this threshold. Plots were sampled with a standard 2.5- × 2.5-ft black cloth shake sheet by placing the sheet between two rows and vigorously shaking plants to dislodge insects. On each date, two shake sheet samples were taken on the center of two rows (10 row ft total) of all plots. Plant bug control was evaluated 24 Jul, 4 days after initial application (4 DAA), 28 Jul (8 DAA), 4 Aug (4 DAB), and 9 Aug (9 DAB). Yield was taken 2 Oct by harvesting the two center rows with a spindle picker modified to collect data for small plots. Immature tarnished and total plant bug data 4 DAA were log transformed (x + 1) and total plant bug data (4 DAB) were square root transformed (x + 0.5) prior to the ANOVA and F-protected least significant difference (LSD, P < 0.05) to distinguish treatment mean differences. Actual nontransformed means are presented in the tables.

Sixteen honey bee (Apis mellifera L.) colonies were placed in four different agricultural landscapes to study the effects of agricultural landscape and exposure to pesticides on honey bee health. Colonies were located in three different agricultural areas with varying levels of agricultural intensity (AG areas) and one nonagricultural area (NAG area). Colonies were monitored for their performance and productivity for one year by measuring colony weight changes, brood production, and colony thermoregulation. Palynological and chemical analyses were conducted on the trapped pollen collected from each colony and location. Our results indicate that the landscape’s composition significantly affected honey bee colony performance and development. Colony weight and brood production were significantly greater in AG areas compared to the NAG area. Better colony thermoregulation in AG areas’ colonies was also observed. The quantities of pesticides measured in the trapped pollen were relatively low compared to their acute toxicity. Unexplained queen and colony losses were recorded in the AG areas, while colony losses because of starvation were observed in the NAG area. Our results indicate that landscape with high urban activity enhances honey bee brood production, with no significant effects on colony weight gain. Our study indicates that agricultural crops provide a valuable resource for honey bee colonies, but there is a trade-off with an increased risk of exposure to pesticides.