Studies On The Small Green Leafhopper, Empoasca Vitis (G(?)the), And Its Egg Parasitoids In Fujian Tea Plantations

Studies on the small green leafhopper, Empoasca vitis (Gothe), and its egg parasitoids in four tea varieties (Fuyun no.6, Fudingdabaicha, Huangdan and Tieguanyin) were conducted at tea plantations of Fujian Agriculture and Forestry University (FAFU), and Fuan from September, 2005 to October 2006. By dissecting the leafhopper's eggs from the tea shoots under microscope and rearing the parasitized eggs in laboratory, the egg densities of the leafhopper and their parasitoids from the four tea varieties were observed. The main results are as follows:1. Investigation showed that spatial patterns of Empoasca vitis (Gothe) nymphae and adults conformed to negative binomial distribution in tea plantations of FAFU.2. The population dynamic tendencies of Empoasca vitis (Gothe) nymphae and adults in four tea varieties were generally similar from April to October in 2006. The population dynamics of the adult were not significant different, while that of the nymph showed a significant difference by Kruskal-Wallis Test among the four tea varieties investigated.3. The egg densities of the leafhopper in tea shoots among the four tea varieties investigated coincided generally with each other and presented markedly seasonal fluctuation except that a weak correlation between Tieguanyin and Fudingdabaicha, whereas the egg densities of the leafhopper were significant different among the four tea varieties investigated.4. The trends of egg parasitism were basically consistent within the four tea varieties investigated. With the exception of the lower egg parasitism in April, the egg parasitism was keeping a higher level during other seasons, basically in accordance with the egg densities of the leafhopper.5. Investigations in three different tea plantations in Fuan revealed that the leafhopper's egg densities and the mymarid parasitism were not significant different within the 3 tea plantations.6. The life cycle of the mymarid parasitoids inside the eggs of leafhopper in laboratory was preliminary observed under microscope. The time from the host eggs being parasitized to the mymarid's larvae could be seen took about 3.4 days on averages (range 2-5d), from the mymarid larva could be seen to pupa took about 6. 9 days on average (range 5-9d), the pupal stage lasted about 8. 8 days on average (range 7—11d), from the host eggs being parasitized to mymarid adults emerged took about 19.2 days on average (range 15—21d).7. In the laboratory rearing experiment, after giving 20% honey water solution to the adults of mymarid parasitoid as complement nutrient, the life-span of the parasitoids can be prolonged. The adult life-span in both female and male of Stethynium sp. were generally longer than those of Schizophragma sp.