一点缀螟生物学特性及其在云南德宏玉米田的为害调查

Biological characteristics of the stored nut moth Paralipsa gularis(Zeller) and its damage on corn in Dehong Prefecture of Yunnan Province

为明确一点缀螟Paralipsa gularis(Zeller)在云南省德宏州玉米田的发生情况,采用五点取样法在连片种植的夏玉米田块对一点缀螟为害情况进行调查,用随机抽样法研究其在玉米田秸秆和当年仓储的玉米果穗中越冬情况,并观察其形态特征、生活史及生物学特性。结果表明,一点缀螟在德宏州每年发生2~3代,以老熟幼虫在玉米秸秆和果穗中越冬,其中主要以第2代幼虫进行为害,玉米果穗平均被害率达24.3%。一点缀螟雌蛾体长及翅展分别为18.7 mm和30.2 mm,雄蛾分别为13.6 mm和28.2 mm;雌、雄蛾前翅外缘末端均有6个小黑点,雌蛾前翅中央有1个黑斑,雄蛾有2个黑斑;卵为散产,椭圆形,长、宽分别为0.6、0.4 mm;幼虫初为乳白色,大龄渐变为灰黑色,老熟幼虫体长25.9 mm。在室内条件下,一点缀螟的发育历期为52.5 d,其中卵期、幼虫期、蛹期、成虫期分别为7.5、26.4、10.0、8.6 d。

In order to clarify the occurrence situation of the stored nut moth Paralipsa gularis（Zeller）in Denghong Prefecture of Yunnan Province, its damage on corn and overwintering situation were surveyed in the field. The morphological characters of P. gularis were observed, and life cycle and biological characteristics were investigated with continuous rearing in the laboratory. The damage of P. gularis on corn was observed in all the surveyed areas of Dehong Prefecture. There were two to three generations one year, and the 2 nd generation larvae caused more serious damage with 24.3% of injured corn ears. The average body length and the wingspan of female adults were 18.7 mm and 30.2 mm, respectively; for males, they were 13.6 mm and 28.2 mm, respectively. The adult moths had six small black spots on the outer fringes of forewing, and in the middle part of forewing, one dark spot for female and two for male. The fresh eggs were dispersedly laid in milk white and oval, and averagely 0.6 mm in length and 0.4 mm in width. The larvae were milk white at first, and the later instars change to greyblack gradually; the mature larvae were averagely 25.9 mm in length. The lifecycle of P. gularis covered 52.5 d, of which egg, larva, pupa, adult stages were 7.5, 26.4, 10.0, and 8.6 d, respectively, under laboratory conditions.