Studies On The Population Dynamics Of Small Green Leafhopper And Its Mymarids And The Tea Physiological Responses To Small Green Leafhopper Piercing-Sucking

The small green leafhopper (SGL), Empoasca vitis (G?the), was one of major tea pests, which had caused severe damage in south of China. The mymarids were dominant egg parasitoids of the leafhopper in Fujian tea plantations.Studied on the SGL and its egg parasitoids in 4 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, 2007 to November 2008. By plant-flapping, pickting shoots, dissecting the SGL's eggs from the tea shoots under microscope and rearing the parasitized eggs in laboratory, the population dynamic, the eggs density of the SGL and its egg parasitism were observed.The impact of pesticides to the bionomics of the parsitoids and physiological responses to SGL damage stress in tea were preliminary studied for the first time. The results were as follows:From the correlation analysis among the population dynamics of the eggs, nymphae and adults of the SGL in 4 tea varieties, a significant positive correlation was shown. Which indicated that the population dynamics of the SGL were generally similar among the 4 tea varieties. The population dynamics of the SGL had two peaks annually and the first peak was higher than the second one. The egg parasitism of the SGL were basically consistent within the 4 tea varieties investigated. The egg parasitism of the SGL were highest in the winter and lowest on April, which varied with the eggs density of the SGL on tea plants, except for that in the cold season.Investigations at 3 different tea plantations in Fuan revealed that the eggs density of the SGL in tea shoots coincided generally and with significant seasonal responses. The eggs density of the SGL were significantly different among the 3 tea plantations, which was the lowest at Tianxiang tea plantation and the highest at Beimen tea plantation. The egg parasitism of the SGL were not significantly different among the 3 tea plantations. The average of the egg parasitism of the SGL were, the highest (65.92%) at Tianxiang tea plantation and the lowest (54.52%) at Xibing tea plantation.The enzymes of SOD, CAT, POD, PPO and tea polyphenols contents in tea leaves and shoots changed quickly after damaged by SGL. The enzyme activity of SOD, CAT, POD, PPO were significantly different between tea leaves and shoots. The enzyme activity of SOD, CAT, PPO were significantly different among the tea leaves and shoots with 3 different treatments, which was the highest at mechanical injury, the second was damaged by SGL and the lowest was normal tea leaves and shoots. Tea polyphenols content increased slightly after damaged by SGL. From the correlation analysis among the enzyme activity of SOD,CAT,POD, PPO and tea polyphenols content in tea leaves and shoots after damaged by SGL, a significant positive correlation was shown on the enzyme activity of SOD,CAT,POD after damaged by SGL, a positive correlation was shown on the enzyme activity of PPO and tea polyphenols content after damaged by SGL.The orders of mass destruction on different pesticides to mymarids were ranked as :rogor> acetamiprid> imidacloprid> bifenthrin> azadirachtin. The orders of the affections on different pesticides to the longevity of mymarids were ranked as: rogor> imidacloprid> acetamiprid> bifenthrin> azadirachtin. The eclosion rate and the longevity of mymarids were significantly different among different pesticides, but slightly different among different concentrations.