荔枝叶瘿蚊的研究

SOME OBSERVATIONS ON LITCHI LEAF GALL MIDGES

荔枝叶瘿蚊(Mayetiola sp)是国内首次报导的荔枝新害虫。在广州一年发生6代,以幼虫在被害叶上越冬。蛹期11—14天,成虫寿命1—2天,卵期2—4天,幼虫期14—39天。越冬幼虫期可达240余天。成虫产卵于嫩叶背面,幼虫孵出后侵入叶肉并发育形成疱状突起的虫瘿,通常一叶多瘿。幼虫老熟后离瘿入土化蛹,大多数是被蛹,但也有围蛹。本文描述了各期虫态的形态特征。温湿度及荔枝品种对叶瘿蚊种群数量影响极大,“三月红”对其幼虫有高度的生理抗性。目前已发现5种瘿内幼虫的寄生蜂。每年春天,于越冬幼虫离瘿入土或成虫羽化出土前用辛硫磷进行土表施药,对压低第一代虫口密度效果显著;氧化乐果或喹硫磷、杀虫双、杀虫单、敌杀死等与敌百虫混合喷雾对卵及初孵幼虫均有明显的防效。

Litchi leaf gall midges(Mayetiola sp) is a new record of litchi pests in South China. The gall midges had 6 generations each year in Guangzhou area. During winter the larvae hibernated inside the insect gall on the litchi leaf. The pupa stage lasted 11-14 days, and the longevity of adult lasted 1-2 days. The female adult laid eggs on young leaves of the crop, and the egg stage lasted 2-4 days. The larvae caused serious damage to young leaves by formation of galls and perforated holes on leaf blades. There were 3 larval instars. Then came the larval stage which lasted about 14-39 days, but larvae stage of hibernation lasted 240 days. The mature larvae pupated in the subsoil, forming mostly obtect pupae, with very few coarctate pupae. Detailed morphological and bionomie descriptions of the developmental stages of this species are given. Of all the litchi varieties observed, Sanyuehong was found to be the only variety resistant to the leaf gall midges. Five parasites of larvae were also observed and found inside the galls. The best time to control litchi leaf gall midges was found to be in spring, just before the adult eclosion period began. Methods of control included soil broadcast with 50% Phoxim at a rate of 7.5 kg/ha, which could provide an effective control of litchi leaf gall midges, and spray of blade surface of young litchi leaves with insecticides such as Quinalphos, Omethoate, Dimehypo, Monosodium salt of Dimehypo or Deltamethrin mixed with Dipterex which also could provide an effective control of eggs or larvae of litchi leaf gall midges.