【摘要】 玉米螟是玉米、杂粮、棉花等作物的大害虫。赤眼蜂是抑制玉米螟危害的重要因素之一。经调查发现我国寄生于玉米螟卵的赤眼蜂有8种,其中玉米螟赤眼蜂Trichogramma ostrininae Paag et Chert占总数的98％以上,分布亦广,是优势种。 我省释放人工繁殖的赤眼蜂防治第一代玉米螟的效果达80％左右,相当于施用滴滴涕颗粒剂;防治第二代玉米螟因受不良气候条件的影响,防治效果不稳定。更多还原

【Abstract】 The study of Trichogramma in controlling corn borer in Jiangsu Province was started in 1959. Our suvey revealed that the eggs of corn borer in China were parasitized by Trichogramma ostriniae, T. dendrlolimi, T. confusum, T. japonicus, T. clo-sterae, T. evenescens, T. leucaniae and T. sp. T. ostriniae distibuted widely in the country and it was estimated that 98% of the Trichogramma populations could be identified as T. ostriniae which might play an important role to suppress corn borer populations in the fields.The adults of T. ostriniae emerging from overwintering larvae or prepupae appear in the first decade of April. There are 16 to 17 generations in each year and hibernation occurred in the host eggs in early November. At 25℃ the generation was completed in 11 days.The dispersal distance of the adult wasps as determined with 32P tracer method was shown to be within 20 meters from the releasing point two days later at 23℃ and with wind velocity varied from 5.5 to 7.9m/s; and 66.7% of the wasps was found within 10 meters. On the third day after releasing 11.1% of the wasps was found at a distance of 50 meters. The activity of the wasps was usually affected by temperature and humidity.This species used to parasitize the eggs of cutworms Agrotis spp. and eould also parasitize Attacus cynthia ricini, Dendrolimus spp. and Corcyra cephalonica. For propagation the fresh eggs of Dendrolimus stored in the refrigerator at 0°-℃ up to 20 days could still be used, but the longer the time of storage the less the effectiveness. 26℃ was the optimal temperature for propagation.Field tests for evaluating the effectiveness of T. ostriniae in controlling corn borers on spring corn were conducted in 1964-1965. The wasps were released for 3 to 4 times for the corn crop and a total of 8000 to 15000 wasps were used per mou. The rate of parasitism ranged from 64.7% to 87.0% of the treated areas as compared with 24.5% to 35.2% by the endemic population of the wasp in the check plot. The density of borer population in the treated areas was found to be 12 to 23.5 larvae per hundred corn plants while 61 to 73.5 larvae were found in the check plots. But comparable effectiveness was not obtained in the summer corn crop for controlling the second and third generations of the corn borer, porbably due to the higher temperature and rain-strorms which might adversely affect the activity of the wasps in the field.更多还原