糠片蚧生物学特性观察

STUDY ON THE BIOLOGY OF CHAFF SCALE(Parlatoria perg(?)dii Com(?)t.)

糠片蚧卵发育的起点温度为6.78℃,孵化积温为102.2日度。在15—34℃温度范围内,发育速率随温度升高而加快,孵化率则降低。在28℃恒温下,世代历期为42天,雌蚧产卵期可达50余天,平均每雌产卵55.5粒,种群趋势指数Ⅰ=11.0,内禀增长率 r_m=0.259,存活曲线为 DeveeyⅢ型。雌成蚧是田间存在的主要形式。越冬后第一、二代幼蚧发生比较整齐,是药剂防治的关键时期。

The lowest egg developmental temperature of chaff scale is 6.8℃.The effective cumulative temperature of the egg is 102.2 day-degrees.The development rate and the mortality rate of the egg are increasingas the temperature increases from 15-34℃.In the case of constant te-mperature 28℃,a generation losts 42 days,55.4 eggs per female.Theindex of population increase Ⅰ=11.0,the intrinsic rate of increase r=0.259.Its survive curve is Deveey type 3.According to the fieldstudy,4 generation occur in a year.But the larval scales of the first twogenerations after May are the main targets of chemical control.