广东省甜玉米虫害发生危害规律

The occurrence and damages of insect pests on sweet corn in Guangdong Province

对广东省部分地区甜玉米害虫发生情况进行了调查,初步明确了甜玉米各生育期害虫发生危害的情况。当地甜玉米害虫有亚洲玉米螟、甜菜夜蛾、斜纹夜蛾、棉铃虫和蚜虫,广州还发现红腹灯蛾、毒蛾类及蜗牛危害;甜玉米以5～8月受害虫危害最为严重;在苗期至6叶期,受甜菜夜蛾平均被害率为15.5％～57.3％,而在喇叭口期、抽雄期和乳熟期则受亚洲玉米螟危害较重,其心叶、雄穗以及雌穗和茎秆的被害率分别为75.3％～91％、24.5％～96.5％和83.5％以上。玉米螟对喇叭口期、抽雄期和散粉期植株有较高产卵选择性。

Sweet corn is nowadays becoming one of the important vegetable commodities.Annual acreages have continuously increased because of its high profit and market demand since 1990s,especially in Guangdong Province.However,the insect pests are serious to limit the production of sweet corn.Investigation on the occurrence and damages of insect pests on sweet corn were conducted in Guangzhou and Yuanzhou Town,Boluo County.Field surveys were focused on the insect species and their damages in the two places.It was found that species of the Asian corn borer,Ostrinia furnacalis(Guenee),beet armyworm,Spodoptera exigua(Hubner),Spodoptera litura(Fabricius),and cotton ballworm,Helicoverpa armigera(Hubner) were the key pests often occurring at economic injury levels,Spilarctia subcarnea Walker and aphid,Rhopalosiphum maidis(Fitch),were species rarely occurring at economic injury levels.Data suggested more species of pests were in Guangzhou and heavier damages in Yuanzhou Town.During the year the heavier infestation were from May to August.For seedling to V6 stage,on average,15.5%-57.3% plants were infected with 5.exigua.There were 75.3%-91.0% plants with leaves damaged by Ostrinia Jumacalis larvae from V6 to late whorl stage,24.5%-96.5% tassels were found with Ostrinia Jumacalis larvae during tasselling stage,and over 83.5% of ears and stems suffered injuries from the pest when kernel maturing.When there were fields with different developmental stages of sweet corn in the same area,the Ostrinia furnacalis females preferred to lay eggs in the plants at tasselling,pollen shedding,mid-whorl stages.