为害莼菜的菱小萤叶甲研究

菱小萤叶甲[Galerucella nipponensis(Laboissiere)]是莼菜的主要害虫。在上海地区一年发生5～6代,世代重叠。以成虫在杂草丛、土缝等处越冬,翌年4月下旬至10月中旬为害。在实验室自然温度下,各代完成一世代所需天数依次为26.22、21.60、15.24、16.73、20.63和35天。单雌平均产卵781粒,最多可达2170粒。卵产于叶片正面,呈块状,每块一般18～20粒。第1～5代孵化率为82.13％、74.38％、49.53％、69.53％和56.29％。取食率:幼虫1～2龄为3.63％,3龄为7.56％,成虫为88.81％。第1～4代成虫寿命分别为39.56、43.94、40.00和43.67天,可用乐果、敌敌畏、氰戊菊脂和毒死蜱等杀虫剂在叶面喷雾防治。

STUDIES ON GALERUCELLA N IPPONENSIS (COLEOPTERA) INJURING THE AQUATIC VEGETABLE BRASENIA SCHREBERI

Galerucella nipponensis (Laboissiere) is a serious insect pest of an aquatic vegetable crop Brasenia schreberi. It has 5 or 6 generations a year in Shanghai and the generations overlap. The pest overwinters as adult in weeds and crevices of soil, etc.. It begins to move about in the middle of April and damages the crop from the late of April to the middle of October. Under the naturel temperature in laboratory, the pest completes its generations for 26.22, 21.60, 15.24, 16.73, 20.63 and 35 days, respectively. The fecundity is very high. Each female may produce 781 eggs in average, with the maximum of 2170 eggs. Females deposit eggs in mass on the upper surface of leaves. Generally each mass contains 18-20 eggs. The hatching rate of egg for 1st to 5th generations is 82.13%, 74.38%, 49.53%, 69.53% and 56.29%, respectively. The ratio of food intake for 1st and 2nd instar larva is 3.63%, for 3rd is 7.56% and adult is 88.81%. The life span for 1st to 4th generation is 39.56, 43.94, 40.00, 43.67 days, respectively. A good control can be achieved with spraying 40% dimethoate 1000-2000 x or 80% dichlorovos 1000-1500 x or 20% fenvalerate 2000-3000 x or 40.7% chlorpyrifos 1000 x.