Activity Patterns, Population Dynamics, and Spatial Distribution of the Stick Tea Thrips, Dendrothrips minowai, in Tea Plantations

SIMPLE SUMMARY: We studied the activity patterns, population dynamics, and spatial distribution of Dendrothrips minowai Priesner, one of the most destructive pests of tea plants in tea plantations. A large proportion of D. minowai individuals were caught in traps placed at heights ranging from 5 cm below to 25 cm above the position of tender leaves at the top of the tea plant, with most captures at a height of 10 cm above this position. The flight activity of D. minowai was highest from 10:00 to 16:00 h on sunny days in the spring and from 06:00 to 10:00 h and from 16:00 to 20:00 h in the summer. The distributions of D. minowai females and nymphs on leaves were aggregated according to Taylor’s power law and Lloyd’s patchiness index. The D. minowai populations were dominated by females, and the density of males was high in June. The seasonal prevalence of tea thrips captured with sticky traps in the field was bimodal; adult thrips overwintered on the bottom leaves. The peak periods of activity were from April to June and from August to October. This work provides new insights that have implications for enhancing the efficacy of measures to control D. minowai. ABSTRACT: The stick tea thrips, D. minowai Priesner (Thysanoptera: Thripidae), is one of the most economically significant thrips pests of tea (Camellia sinensis (L.) O. Ktze.) in China. Here, we sampled D. minowai in tea plantations from 2019 to 2022 to characterize its activity patterns, population dynamics, and spatial distribution. A large proportion of D. minowai individuals were caught in traps placed at heights ranging from 5 cm below to 25 cm above the position of tender leaves at the top of the tea plant, and the greatest number of individuals were captured at a height of 10 cm from the position of tender leaves at the top of the tea plant. Thrips were most abundant from 10:00 to 16:00 h in the spring and from 06:00 to 10:00 h and from 16:00 to 20:00 h on sunny days in the summer. The spatial distribution of D. minowai females and nymphs was aggregated on leaves according to Taylor’s power law (females: R(2) = 0.92, b = 1.69 > 1; nymphs: R(2) = 0.91, b = 2.29 > 1) and Lloyd’s patchiness index (females and nymphs: C > 1, Ca > 0, I > 0, M*/m > 1). The D. minowai population was dominated by females, and male density increased in June. Adult thrips overwintered on the bottom leaves, and they were most abundant from April to June and from August to October. Our findings will aid efforts to control D. minowai populations.