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1.榆毒蛾在北京地区,一年两代,每代的历期与季节性气候变化有关。第—代在夏季完成,卵期,约在7月上中旬,幼虫于7月中下旬孵化,至8月下旬化蛹,9月上旬羽化,历期约50日;第二代从秋末到次年春末夏初,卵期在9月上旬至下旬,幼虫9月中下旬孵化至10月中旬前后进入越冬,次年4月中下旬活动至6月下旬化蛹,7月上旬羽化,除越冬期外,历期约120日。 2.榆毒蛾的雌雄性比,1956年统计:第一代雌雄比例(％)为68:32,第二代为56.5:43.5。其产卵量,每雌最多215粒,少为26粒,平均79.1粒。成虫期遇天气晴朗,卵量较多,阴雨天气,产卵量减少。卵的孵化率,在自然条件下,每代都在90％以上。 3.榆毒蛾在北京地区,以2龄幼虫越冬。越冬场所主要在榆树洞穴、裂皮和树下的堆积物内。榆毒蛾成虫不取食,幼虫取食叶片;幼虫1-3龄,趋光性弱,大部在榆树下层,叶片背面,5-7龄,趋光性增强,栖居于榆树上部、叶片表面;成虫夜晚有趋光习性,白天在晴朗的中午前后飞翔数量较多,阴雨和风速在3级以上的夭气停止飞翔。 4.榆毒蛾虫口数量的变化与降雨量及其分布有关。少雨的世代,榆毒蛾数量上升,多雨的世代,其数量下降。如1955年第一代幼虫初期降雨125.5毫米。蛾量较越冬代增长11.8倍,1956年第一代幼虫期降雨529.0毫米,其蛾量较越冬代却有所下降。
1. Elsevier moths in Beijing area, one year and two generations, the duration of each generation and seasonal climate change. The first generation is completed in the summer, the egg period, about mid-July, larvae hatch in mid-late July, pupation in late August, eclosion in early September, the duration of about 50 days; the second generation from the end of autumn to the second Early spring and early summer, the egg period in early September to late, the larvae hatch in mid-late September to mid-October before entering the overwintering, the following year in mid-April to late June pupation, early July feather, except during the winter Outside, the duration of about 120 days. (2) The female to male ratio of the genus Elvish Moth, 1956 statistics: the first generation of male and female ratio (%) of 68:32, the second generation of 56.5: 43.5. The fecundity per female up to 215, less than 26, an average of 79.1 tablets. Adult encounter a sunny weather, more eggs, rainy weather, reduced fecundity. The hatching rate of eggs, in natural conditions, each generation is more than 90%. 3 elm moths in Beijing, with 2 instar larvae wintering. Wintering places are mainly within the alluvial caves, split skin and under the trees of the accumulation. Ulmus larvae fed on larvae without feeding, larvae 1-3 years old, weak phototaxis, mostly in the lower layer of elm, 5-7 years old leaves, phototaxis enhancement, dwelling in the upper part of the elm, leaf surface; Light habits, flying in the sunny before noon during the day the number of more rain and wind speed in the third grade above the air to stop flying. 4. The change of the number of elm moth insects mouth and rainfall and its distribution. Fewer generations, the number of elm moths increased, rainy generations, the number of decline. As early as 1955, the first generation of larvae rainfall 125.5 mm. Moth increased by 11.8 times over the winter, the first generation of larvae in 1956 rainfall of 529.0 mm, the moth than the winter has declined.