四川西部梨黄粉蚜的生活史及发生规律的研究

<正> 梨黄粉蚜Aphanostigma jakusuens Kishidah属同翅目,疣蚜科(phylloxidae)是梨树上重要害虫之一。四川自1969年金川梨区发现危害后,相继在省内其它梨区也有发生,据1977—79年在雅安田间调查,虫果率一般在20—30％左右,个别植株高达70％以上,致使梨果品质低劣、不耐贮藏。

STUDIES ON THE LIFE HISTORY AND BIONOMICS OF APHANOSTIGMA JAKUIENS KISHIDA IN WEST SICHUAN,CHINA

It is known that Aphanostigma jakusuiens Kishida is distributed throughout 43 counties and 2 cities in Sichuan province, among which Jinchuan and Hanyuan are most serious pest regions There are within a year altogether 9-10 generations in Yaan county with only one generation of fundatrix, 6-7 generations of fundatrigenia, one generation of sexuparae and one generation of sexuales. After early November, sexuales deposit their eggs in crevices of twigs or under hats of fruit spurs and live through the winter within them. Eggs hatch in March in the following year. Sexuparae deposit their big and small eggs in the midst of August and they hatch individually as females and males. It is obvious that the generations are overlapping. Field experiment was conducted in 1978-79 and showed that temperature, humidity and rainfall are closely related to its population dynamic. This insect is apt to thrive at an average temperature of 23-27℃, 65-80% RH and less than 10 mm of rainfall for 7 days. usually from the midst of May and to that of July. During the growing season, different pear trees are attacked. Fruits are the most seriously attacked, fruit spur and crevices are less and leaf axilae the least. Different pear species suffer from this pest in varying degrees. Pyrus bretschneideri Rehder is affected more seriously than Pyrus pyrifolia(Burm.) Nakai. It has been found that 5 kinds, of predators and 1 fungus are its natural enemies.