The effectiveness of several pesticides on the adults of woolly apple aphid parasite, Aphelinus mali (Hald.)
zhao sheng-lian1; zhong jian1; tang ting2; zhao xueqing3; gong shen-xin3; zhan aidong2 (1! agro-technical extension station of jiufu township; zhaotong city; yunnan 657004; p! r! china; 2! institute of agro- environment and natural resources; yunnan agricultural university; kuming 650205; p! r! china; 3! plant protection and quarantine station of zhaotong city; zhaotong 657000; p! r! china)