Study On Biological Characteristics And Integrated Control Of Ylobitelus Xiaoi Zhang

Hylobitelus Xiaoi Zhang is a new kind of insect pest species which were founded inoverseas pine plantation, such as Pinus elliottii var. elliottii, P taeda. And it also does harm toPinus massonians, Taiwan pine, and Amandi pine. Hylobitelus Xiaoi Zhang was firstlydiscovered in Wugong shan, Anfu county, Ji'an city, Jiangxi province in 1988. The firstappearance in Hunan province was in Ping shi county, Zixing city, in October, 1994. It was foundin 21 counties of Hunan Province in 1999, the area of suffered regions amounts to 10,000 hm~2,the number and area of suffered regions were increased to 35 counties and 17,300 hm~2 separately.Hylobitelus Xiaoi Zhang is the key factor which caused negative effect to 6,130,000 mouoverseas pine plantation. This paper based on disaster region, Anatomy and regular observationwere used in the studies of Hylobitelus Xiaoi Zhang's life-history and environmental factors.Areas of disaster region were decreased through controlling technology. Results are asfollowing:1. life-history and biological habits of Hylobitelus Xiaoi Zhang were found out.Hylobitelus Xiaoi Zhang has one generations every two years in Hunan province. It over-wintersas adult, larvae and pupae. The peak of hatched eggs is from late May to early June. Eggs period:late April to mid-August, larvae period: early June to next late September; pupae period: earlySeptember to next late March; adult period: late September to next mid-August. Generationsoverlap was obvious. Adults' fly ability is weak, and it has no phototatic reaction toward lightand also has anabiosis. Adults are active at night, but mated at days.2. Studies on environmental factors.Harm levels were depended on host species. Pinus elliottii var. elliottii's mean larvalpopulation density and damage is larger than Pinus massonians. 6-10 years old pine trees wereseriously damaged, if there were so large quantities of such insect pests. Larger the area ofvegetation is, the plantation will be more seriously damaged. And some other factors caused thedifference of number of this insect pests, such as the height of vegetation. 3. Carry out scientific experiment to gain the practical control methods.Carries out manual controlling, fumigation, medicine injection and spreads controllingexperiment, the manual controlling effect rate is above 80%, fumigation rate is above 97%,injection controlling above 82%, spreads rate is from23% to 62%.Area of manual controlling is up to 6700 hm~2, medicine injection region in Jiangyong county andShuangpai county is 810 hm~2. Through integrated controls, project control area(including Zixingcity, Dong'an county, Nanyue region, Louxin region) that investigated in 2003 was 6200hm~2, has decreased to 4330 hm~2 in 2005, and it almost decreased 1870 hm~2. Ratio of infested slashpine trees decreased from 52% to 6%, mortality rate decreased from 12.25% to 1.03%. Thoughthe occur area has expanded in hunan province in 2005, and occur area decreased about 3000hm~2.