关键词: 德清真片胸叶蜂, 产卵选择, 理化性状, 营养元素, 防治

Abstract:

Objective: Phyllostachys edulis is a main bamboo species in term of both economic and ecological benefits and the sawfly Eutomostethus deqingensis, a defoliator pest, severely attacks the bamboo. It is helpful for effective control the pest by surveying its oviposition habits in different ecological habitats and the effects of host nutritional conditions on its ovipasition selection. Method: The bamboo forests with different structure and environmental conditions were randomly selected as sample sites, then the damage rate of E. deqingensis and the total number of eggs laid in each bamboo were investigated. Meanwhile, the factors, water content, the content of nutrient elements(N, Na, K, C), and the thickness of upper and lower epidermis of bamboo leaves were measured. Finally, the relationships between the factors with oviposition preference of E. deqingensis adults were analyzed by Stepwise Discriminant Analysis. Result: 1) Most eggs were laid on the leaves in the middle and high branches of the bamboo, and the total number of eggs on the leaves of the bamboos grown in the slope bottom (3 835.0 ±385.2 per bamboo) was significantly higher than that in the slope upper part (864.5 ±215.5 per bamboo, P < 0.01). 2) Bamboo age had a significant impact on oviposition preference of E. deqingensis, and the number of eggs on leaves of one-year-old bamboo(3 954.6 ±1 247.4) was significantly higher than that of two-year-old bamboo(144.3 ±49.3, P < 0.001). The oviposition preference showed significant positive correlation with the water content of bamboo leaves(54.90% for newly grown leaves and 51.99% for two-year-old leaves, P < 0.05), no significant correlation with the thickness of leaf epidermis(P>0.05).3) There were significant differences in N and Na content(P < 0.01)between newly grown leaves and two-year-old leaves, while no significant differences in C and K content were found. The result analyzed by Stepwise Discriminant Analysis showed that N content was the dominant factor affecting oviposition preference of E. deqingensis, followed by Na. Conclusion: E. deqingensis adults prefer to laying eggs in the newly grown leaves of the bamboos growing at the bottom of slope, especially the middle part of the bamboos. The age, water content, and the content of N and Na of leaves are significantly related to the oviposition preference of this insect. The pesticide-injecting in the newly grown bamboo cavity is an effective method to control E. deqingensis.

Key words: Eutomostethus deqingensis, Phyllostachys edulis, oviposition preference, physicochemical characteristics, control