北京房山地区桑蟥发生的主要特点及化学防治方法

Major Characteristics and Chemical Control of Rondotia meniciana Moore Occurring in Fangshan District of Beijing City

桑蟥（Rondotia meniciana Moore）是桑树的主要害虫之一,在我国大多数蚕区桑园均有分布,以幼虫取食桑叶危害。调查北京房山地区的桑蟥1年发生2代,有一化性和二化性,以二化性居多。一化性桑蟥产有盖卵块越冬,二化性桑蟥产无盖卵。第1代桑蟥幼虫为害期在6月中旬至7月下旬,第2代桑蟥幼虫为害期在7月下旬至9月上旬,造成夏秋季桑叶减产。田间桑树喷施4.5%高效氯氰菊酯乳油1 500倍稀释液,桑蟥幼虫的虫口减退率可达94.7%;喷施2.5%溴氰菊酯乳油2 500倍稀释液,桑蟥幼虫的虫口减退率为94.3%。在桑蟥幼虫发生盛期7月上旬和8月上旬,采用上述药剂防治可以有效控制其危害。

Rondotia meniciana Moore is one of the major mulberry pests that distributes in most sericultural areas of China and brings damage to mulberry by feeding on mulberry leaf at larval stage. Our survey indicated that R. meniciana reproduces two generations annually in Fangshan District of Beijing City. Both univoltinism and bivoltinism are present. Yet, the majority are of bivoltinism. The univoltine adult lays covered eggs for overwintering, while the bivoltine adult lays un-covered eggs. Its first generation larvae mainly cause damage from mid-June to late July, and its second generation larvae mainly cause damage from late July to early September, which lead to decline of mulberry leaf yield in summer and autumn. The population of R. meniciana larvae could be reduced by 94.7% and 91.3% when 1 500 times diluted so- lution of 4.5% beta-cypermethrin emulsifiable solution （EC） and 2 500 times diluted solution of 2.5% decamethrin EC were sprayed onto mulberry trees, respectively. It turns out to be an effective way to control this pest by spraying the above two chemicals during outbreak of R. meniciana larvae in early July and early August.