| Lycorma delicatula (Homoptera: Fulgoridae) is widely distributed in Beijing, Liaoning,Shandong, Hebei, Shaanxi, Shanxi, Henan, Sichuan, Zhejiang, Jiangsu, Guangdong, Taiwanprovinces... The main hosts of L. delicatula in Beijing are Ailanthus altissima, Toona sinensis,Ailanthus altissima, Robinia pseudoacacia, populus spp., Salix spp., Ulmus pumila, Prunussalicina, Sorbaria kirilowii, Malus micromalus, Prunus persica, Albizia julibrissin, Ligustrumlucidum and so on. In recent years, its damage have become more and more serious inorchards, including grape and pomegranate etc.. Owing towaxy secrereted on the nymph’sbody, it is difficult to control with chemical pesticide. At present, there are many studies on thechemical control techniques of L. delicatula. However, considering of the the pollution forfruits and environment, the biological control strategy should be conducted necessarily. For thepropurse, the parasitoid of the pest was investigated and an egg parasitoid Ananstatus sp.(Hymenoptera: Eulophidae) was found and studied, including mass rearing techniqueof theparasitoid indoor, as well as its ecological characteristics were studied. The main results of thepresent studies are as follows:(1) L. delicatula has one generation per year in Beijing, and overwintered as egg.Overwintered eggs began to hatch in late April of next year. Hatching peak was in early May.There were four instars of nymph. Adults emerged in late June, then mating and laying eggs inlate August. Eggs were mostly laied in egg-case at sunny shade of trunk, which was arrangedin5～10lines and10～30eggs in each line. There was grey loose and powdery waxy secretedby female adult and covered on egg-case like soil clod. Nymph and adult were good at jumpingand prefered to gather together in host tree trunk and leaf. The mouthpart thrusted into the planttissue deeply when they were feeding, which can made wounds infected sooty fungi.(2) When L. delicatula laying eggs, they prefered poplar than Ailanthus altissima andwillow. The successful eggs hatching rate was above55%in the three host trees. The parasitic rate of Ananstatus sp. on the three host trees were44.34%(poplar),21.08%(willow),9.08%(Ailanthus altissima) respectively.(3) The five species of natural enemy of L. delicatula by investigation were found andthey were as follows: egg parasitoid: Ananstatus sp.(which was identified by Professor YangZhong-qi, as an undescribed new species to science); predators: Monomorium pharaonis,Nephila clavata, Araneus ventricosus and Paratenodera sinensis. The natural parasitic rate ofAnanstatus sp. was20%～90%with an average44%in nature.(4) A mass rearing technique for the egg parasitoid Anastatus sp. was conducted. Withtemperature25±1℃and relative humidity65±5%, L/D=12/12), it has seven or eightgenerations a year. Eclosion period of the parasitoid was from late April to early May. The timefor the parasitoid complete a generation was23～33days. The experiments indoor showed thatfemales of Ananstatus sp. could survive100days when tussur’s eggs in a substitute host. Onefemale which reared in glass tube could lay64eggs, with98eggs at most, and the femaleswhich reared in propagation could lay232eggs in an average. the parasitism rate on substitutehost was77.3%, the eclosion rate was78%. The result showed that the egg parasitoid specieshas high value in biological control of the pest.(5) There were two eclosion periods of Ananstatus sp. in field: The first eclosion periodwas from late April to early May, the second period was from late August to early September.The first eclosion number was about80%and the second eclosion number was about20%.After emergence Ananstatus sp. audlts soon began to search for eggs of L. delicatula and thenlaying eggs. They overwintered as mature larvae inside the eggs of its host L. Delicatula andemerged in late March to early April when daily average temperature reached15℃. Only about15%larvae diapaused and eclosion in August and September. When rearing indoor, larvaebecame diapaused when room temperature was below17℃. However, when room temperaturewas above20℃, they could developand emergent normally... |
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