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

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: R2 = 0.92, b = 1.69 > 1; nymphs: R2 = 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.

Aggregation pheromones released by nymphs of the stick tea thrips (Dendrothrips minowai): identification and analysis of their potential utility for controlling thrips in tea plantations

“…However, current methods for controlling this thrips mainly rely on pesticide applications, which can seriously decrease tea quality and safety (Tewary et al, 2005;Ye et al, 2014;Nakai & Lacey, 2017). The aggregated distribution of D. minowai nymphs and females on tea leaves has been studied in detail (Zhang et al, 2019). Our analyses revealed a lack of aggregated D. minowai males in tea gardens, which differs from those of male aggregation observed for other thrips.…”

“…However, D. minowai nymphs and females form aggregations on tea leaves, but the males do not. A recent study indicated the D. minowai nymphs aggregate more than the females in tea plantations (Zhang et al, 2023). In addition, the aggregation pheromones may be secreted by both sexes and/or during the immature stages (eggs, nymphs/larvae, and pupae) (Wertheim et al, 2005).…”

“…The tests were conducted in a darkened room set at 26 ± 1°C and 65 ± 1% relative humidity. All bioassays were conducted between 8:00 and 18:00, which coincides with the period of their activity in tea plantations (Zhang et al, 2023).…”

Identification of aggregation pheromones released by the stick tea thrips (Dendrothrips minowai) larvae and their application for controlling thrips in tea plantations

“…3,4 Both adults and larvae of D. minowai utilize their piercingsucking mouthparts to feed on the tender leaves of tea plants, leading to detrimental effects such as stunted growth, color fading, and even the development of leaf stiffness or brittleness. 5,6 Notably, there has been an increase in the incidence of D. minowai infestations, which results in higher tea plant damage annually and in turn significantly impacts tea yield and product quality. 5,7 Currently, control measures for D. minowai rely heavily on the application of chemical pesticides, including spinetoram, chlorfenapyr, and bifenthrin.…”

“…35 The aggregated distribution patterns of D. minowai larvae and adult females on tea leaves have been described in a previous study, the findings of which revealed that the larvae and adult females exhibit aggregation tendencies primarily along the veins of tender leaves. 6,36 Generally, adult females tend to assemble on the anterior surface of tea leaves, in clusters comprising ∼10-20 individuals. By contrast, larvae predominantly aggregate on the lower surface of leaves, forming groups of around 20-30 individuals.…”