Study On Population Monitoring Of Leptocybe Invasa Fisher&La Salle In Chongzuo City

Leptocybe invasa Fisher&La Salle is a species of Eulophidae in Chalcidoidea belonging to Hymenoptera, which was firstly discovered on Eucalyptus plant as a kind of destructive insects in Middle East and Mediterranean areas in2000and was described as a new species by Fisher and La Salle from Australia in2004. It was firstly seen on fast-growing Eucalyptus at Pengzuling Hill, Zhenjiang Village, Dongxing City, Guangxi Autonomous Region, China in April of2007. Twigs and petioles of Eucalyptus formed galls after that this insect infected. Although a few researchers monitored its population diffusion and harming process, the regularity of its population diffusion and harming process in Chongzuo City was not described clearly. To prevent the outbreaks of Leptocybe invasa on the Eucalyptus, an investgation on population diffusion and harming process was made so that the outbreaks can be predicted correctly and development of forestry economy can be guaranteed.Chongzuo city was the area that Leptocybe invasa invaded earlier than other cities and injury and disaster was more serious in Guangxi. Author investigated on population monitoring of Leptocybe invasa in all city (Fusui County, Xinxian County, Tiandeng County, Ningming County, Longzhou County, Pingxiang and Jiangzhou District) from2008to2011. The main results were as follows:1. From2008to2011, injury of Leptocybe invasa was found in7counties (city, district), and the rate of diffusion was100%, which has no correlation with the geographic positions and the insect survived in extensive area.2. There was a certain corelation between the mass outbreak of Leptocybe invasa and distrrbution of local susceptible strains (DH201-2).The larger plantation of DH201-2is, the larger population of Leptocybe invasa. Based on dimensional parameters calculation, it showed that the diffusion coefficient was greater than1, clumping index, Ca is greater than0, the rest of the indexes are distributed in the aggregated scopes, and Leptocybe invasa obviously aggregately distributed in DH201-2stand.3. The longest natural diffusion distance of Leptocybe invasa was100m, but damage degree to the DH32-29was relieved than others in young forests.4. The attraction of color sticky board to Leptocybe invasa was tested and showed that the taxis of Leptocybe invasa adults to yellow sticky board was significantly stronger than blue and other colors, Leptocybe invasa adults have the phototaxis so that color sticky board and light trap which can be applied to Leptocybe invasa monitoring by the insect phototaxis and phototaxis.5. According to the survey, relationship of resistance of5varieties of Eucalyptus in Chongzuo City to Leptocybe invasa was that E. urophylla×E. grandis "DH32-26"=E. urophylla×E. grandis "DH32-28"=E. urophylla×E. grandis "DH32-29"> E. urophylla×E. grandis "DH33-27"=E. grandis×E. urophylla "Guanglin-9". Through the improved victims stand, the density of Leptocybe invasa and possibility of insets outbreaks can be greatly reduce and prevented.