Spider foraging strategies dominate pest suppression in organic tea plantations

Abstract

Organic management of crops generally leads to greater predator richness. However conservation of natural enemy species richness does not consistently strengthen herbivore suppression. Here we explored relationships between abundance and diversity of predatory spiders with two distinct foraging strategies and their prey, leafhopper pests. In three organic tea plantations, we investigated abundance of these spiders, and population dynamics of an important tea green leafhopper pest, Empoasca vitis (Homoptera: Cicadellidae). We found that abundance and diversity of actively hunting spiders were significantly negatively correlated with leafhopper pest populations, but sit-and-wait spiders were not. The latter may have been limited by intraguild predation or other trophic interactions. Furthermore, there was no significant correlation between total spider and leafhopper numbers. Our study thus suggests that predator foraging strategy might be a key functional trait that can help to explain variation in pest suppression in agricultural systems.

A Comprehensive Model of Consumers’ Perceptions, Attitudes and Behavioral Intention toward Organic Tea: Evidence from an Emerging Economy

“…Hoffman et al [12] suggested that factual concernment and perceived concern are the two important factors that determine consumers' intention to purchase organic foods. Several other studies also investigated factors regarding to health and environmental protection as main antecedents of organic food consumption [13,14,[16][17][18]20,21]. In sum, these studies have provided rich evidence on the factors that influence consumers' purchase behavior toward organic foods.…”

The reproductive strategy and the vibrational duet of the leafhopper Empoasca vitis

“…In recent years, several integrated pest management (IPM) approaches have been tested to control E. vitis population density, such as the use of nonsusceptible cultivars, and techniques of landscape management to favor the occurrence of predators and parasitoids (Decante & van Helden, 2006;Pavan & Picotti, 2009;Fornasiero et al, 2015;Liu et al, 2015). However, none of them have been applied extensively to the field and population control of E. vitis is still achieved mainly with pesticides.…”

Use of a Lower-Volume, Surface Pesticide Spray Conserves Spider Assemblages in a Tea Field

“…In tea fields, Kosugi (2003) has reported the predatory quality of Trachelas japonicus Bösenberg & Strand (Araneae: Corinnidae) and Philodromus subaureolus Bösenberg & Strand (Araneae: Philodromidae) on Empoasca onukii Matsuda (Hemiptera: Cicadellidae), keeping their populations under control. Spiders can control the density of leafhoppers in tea fields ( Liu et al 2015 ), with larger spider populations effectively reducing populations of E. onukii and Scritothrips dorsalis Hood (Thysanoptera: Thripidae) ( Goto et al 1995 ). Shiraki and Ohashi (1992) have shown that the population density of spiders and other natural enemies are higher in pesticide-free tea fields than in those sprayed with pesticides.…”