小麦蚜虫为害特性及防治指标研究

采用人工控制虫口密度，研究小麦育期蚜虫密度对小麦产量的影响。结果表明，麦蚜虫在小麦不同生育期的危害不同，开花期为害最大，灌浆期次之。在拔节期，当害虫密度低于２头／株时，由于植株的超补作用，产量可相对增加，只有当累积蚜量达到５１．５虫．ｄ／株时，才会造成明显的产量损失。小麦不同时期的防治指标，拔节期５１．５头．ｄ／株。抽穗扬花期４．４头／穗，灌浆期７．８头／穗。乳熟期后，麦蚜数量急剧下降，不再造成危

STUDIES ON THE DESTRUCTIVE CHARACTERISTICS AND PREVENTIVE INDEXES OF WHEAT APHIDS

The effects of the population density of wheat aphids at different growth stages on wheat yield were investigated under controlled conditions with the density of the pest regulated. The destructive levels of aphids were found to vary at different' growht stages of the crop. The flowering stage appeared to be most susceptible, followed by the milk stage. When the number of aphids was lower than 2 per plant at elongation stage,the yield tended to increase,instead,owing to the compensation function. Only when the number of aphids was 51. 5 per plant or more,did wheat yield decrease significantly. The preventive indexes at different growth stages are recommended as follows; elongation stage-51. 5 per plant;heading stage-4. 41 per plant;seed-filling stage-7. 8 per plant. After the milk-ripe stage, the number of aphids will drop sharply and. therefore, no controlling measures are necessary.