Abstract:
The effect of insecticides with different characteristic on natural enemies was evaluated in Henan wheat field.The results showed that the application of insecticides could cause different level reductions in the population of predators.Population numbers of predators in plots treated with abamectin,pirimicarb,imidacloprid and omethoate were reduced by as much as 19.69%,41.77%,45.75% and 82.69%,respectively,from 5d to 10d after treatment.Pirimicard and imidacloprid could cause significant relative long term reductions in ratio of ladybird to aphids.The ratio of ladybird to aphids in the plots was 1∶31~149 and 1∶34~85,respectively,from 5d to 20d after treatment in treatment plots.Omethoate could only cause relative short term reductions in the ratio of ladybird to aphids.The ratio of ladybird to aphids from 5d to 10d was 1∶0~28,and the ratio reached 1∶265 in 15d after treatment.The effect of abamectin on ratio of ladybird to aphids was very little.The effect of all used insecticides on parasitism of aphidius was not significant.The IPM was put forward that pirimicarb at 2.5(a.i.)g/667m 2 or 1(a.i.)g/667m2 could be used as ideal chemicals against wheat aphids in wheat field.
Key words:
Insecticides,
Natural enemies,
Ratio of ladybird to aphids,
Parasitism,
IPM
CLC Number:
LIU Aizhi, LI Sujuan, WU Yuqing, LI Shigong, BAI Huaijin. Effect of Insecticides with Different Characteristic on the Natural Enemies in Wheat Field[J]. ACTA AGRICULTURAE BOREALI-SINICA, 2001, 16(4): 100-103. doi: 10.3321/j.issn:1000-7091.2001.04.021.