西藏飞蝗食性及其防治指标

Feeding habits and economic threshold of Locusta migratoria tibetensis

采用室外笼罩法测定西藏飞蝗Locusta migratoria tibetensisChen的食性、食量及其对青稞和牧草造成的产量损失,并初步制定其防治指标。结果表明:西藏飞蝗1～2龄蝗蝻喜食牧草,3龄后喜食青稞和冬小麦;其在草地(亚高山草甸)、青稞和冬小麦3种植被上均能获得必需的营养并完成发育,而在沙棘Hippophae rhamnoides和白菜地则不能完成整个生活史;西藏飞蝗的取食量在1～3龄时很小,5龄和成虫期为暴食期;西藏飞蝗取食青稞和牧草的防治指标分别为3.01和4.44头/m2。

The feeding habit, quantity of food-taking of Locusta migratoria tibetensis Chen and the output loss of the highland barley and pasture grass by the pest were studied in this paper, and then the action threshold was worked out. The results showed that 1^st-2^nd instar nymphs of locust fed mainly on pasture grass, after the 3^rd instar, Locusta migratoria tibetensis fed mainly on highland barley and winter wheat. The locusts could obtain the necessary nutrition on pasture grass （subalpine meadow）, highland barley and winter wheat for its growth and development in its life history, but it couldn＇ t complete its life history when it fed on Hippophae rhamnoides and Chinese cabbage. The quantity of food-taking of the 1^st-3^th in- stars nymphs was very low, but the quantity of food-taking of the 5^th instar nymph and the adults was huge. The action threshold for this pest feeding on highland barley was 3.01 nymphs per square meter, and the action threshold on oasture grass was 4.44 nymphs per square meter.