Review on the investigation and protection measurements of spiders in tea gardens in China

Abstract

Bio-control of tea pests by spiders in China has been reviewed by Chen Yinfeng et al. Spiders constitute 65% to 90% population of all the predacious natural enemies in tea gardens of China. Some 290 species belonging to 28 families predate on harmful insect pests and play a significant role in natural control of tea pests. The review profiles their occurrence, habits and hunting ability. Spiders prefer habitat with mild temperature and high humidity. Presence of interplant trees and some weeds help in building up their populations. However, spiders are sensitive to pesticide sprays, which reduce their populations by 20% to 90%. Both the hunting and net-forming spiders have an enormous potential as agents of natural control of tea pests. They are voracious consumers of insect pests. On an average, each spider eats up 20 - 120 insect larvae, nymphs and adults per day. Female spiders are better hunters of insect pests than males. Cases have been reported where a single female consumed more than 295 adult hoppers in one day. This review suggests agro-techniques to regulate pest-predator ratio and maximize benefit by spider-actuated control of harmful pests in tea gardens.