The Occurrence And Harm Of Didesmococcus Koreanus From Different Provenances Of Armeniaca Sibirica

The population density of Didesmococcus koreanus, the ratio of infested trees of Armeniaca sibirica was investigated in 12 different provenances in Inner Mongolia Forest Tree Breeding Center. The sensitivity and insect resistance of different families and provenances to Didesmococcus koreanus were measured, the best provenance and family of insect resistance was obtained, and it provided basis for insect resistant breeding. The results were as following:(1) Population density of Didesmococcus koreanus was different in differen t provenances, in which Bahrain Right Banner was the least (7.65), next came Chaersen (11.90), Kerrchin Right Middle Banner was biggest (54.46), next ca me Wulashan (46.11). The population density of insect was different in differen t family of different provenances. The biggest was No.18 (793) in Kerrchin R ight Middle Banner, secondly was No.36 (776) in Aohan Banner.(2) The ratio of infested trees of Armeniaca sibirica was different in diff erent provenances, Charlson Banner (8.8%) and Bahrain Right (19.2%) were le ss, Kerqin Left North Banner (90.0%) and Wulashan (98.6%) were more. The ratio of infested trees in different families was different,Liangcheng No.34,23,2 4 and 29 families, Hexigten Banner 13,18,46,48,2,30,38,3 and 6 family, Kezuoh ouqi 11,47,40,53,31,45,32,46,41,33,39,25,38,13,23,50 and 16 families, Aohan ban ner,19,29,8 families and Wulashan 17,18,27,34,32,39,36,15and 47 home system.(3) The pest index was different in different provenances, it was least in Charlson (4.53), and next came Jarud banner (12.14), Liangcheng (60.30), Kerqin Left North Banner (63.68) and Wulashan (63.72) were more. Pest index was different in different families,12 provenances in pest index minimum for Chaersen provenances 5, 46,45,44,42,21,38,12and the No.27 family. The most family was No.8 in Wulashan.(4) The sensitivity and insect resistance were analyzed by DSI (Didesmococcus sensitivity index) which was a sensitive index of pest, it indicated that the sensitivity of Didesmococcus koreanus to Armeniaca sibirica in Wulashan was the strongest and insect resistance was the weakest in 12 provenances, it was opposite in Caersen. The results was same to the evaluation result basis on pest.