大突肩瓢虫生物学及田间种群消长研究

STUDIES ON THE BIONOMICS AND POPULATION FLUCTUATIONS OF SYNONYCHA GRANDIS (THUNBERG)

大突肩瓢虫Ｓｙｎｏｎｙｃｈａ ｇｒａｎｄｉｓ（Ｔｈｕｎｂｅｒｇ）在云南开远１年发生４代，以成虫在蔗茎老叶鞘内越冬。日均温２６．６～２７．８℃下，卵期３－４天，幼虫期９－１２天，预蛹期１天，蛹期４－５天，成虫产卵前期２０－２５天，１个世代历期３７－４６天；日均温２４．５—２５．５℃下，卵期５－９天，幼虫期１４－２１天，预蛹期１－２天，蛹期５－８天，成虫产卵前期２５－３０天，１个世代历期４５－５５天。（第４代）（越冬代）各虫态历期延长，全代历期长达２５０余天。成虫、幼虫均捕食甘蔗绵蚜。大突肩瓢虫田间种群动态：６月初开始在蔗田出现，８－１０月种群数量明显增长，１１月间形成高峰，１２月开始越冬。

Synonycha grandis (Thunberg) developed for 4 generations per year in Kaiyuan County of Yunnan Provice and overwintered with the adult stage. At 26.6 ~27.8℃,the duration of a gen eration; egg; larva; pupa; and preoviposition was 37- 46; 3~ 4; 9 ~12;4~5;and 20~25 days, respectively. At 24.5~25.5℃, the durations of: a generation; egg; larva; pupa; and preoviposition was 45 ~ 55; 5~9; 14~21; 5~8; and 25 ~ 30 days, respectively. Both adults and larva could prey on Ceratovacuna ranigera Zehntner. In sugarcane fields the onset phase of Synoncha grandis (Thunberg) was early June, populations tended to increase obviously from Au gust to October reaching a peak in about November and the predator began to overwinter in Decem ber.