Acta Entomologica Sinica (1997) 40, S165-S171

Jincai Wu, Jianxiang Xu, Guosheng Li, Xianian Cheng and Deben Yong (1997)
[Impact of several insecticides on the predation function of Pirata subpiraticus]
Acta Entomologica Sinica 40 (Supp.), S165-S171
Abstract: So far main evaluating method about effect of pesticides on natural enemies has been concentrated on their lethal rate resulted and rarely on their predation function. Impacts of three insecticides. shachong-shuang, methanidophos and buprofezin on the predation function of Pirata subpiraticus on brown planthopper were studied in this paper. Decrease rate of predation function, FD= [ Sigma{t=1 - TR} (D_t+S_t X FD_t)] /TR X 100 was proposed as comprehensive evaluation of impact of insecticides to natural enemies, where D_t=death rate of natural enemy at t time, S_t=survival rate of natural enemy at t time, FD_t=decrease rate of predation function at t time and TR=duration of predation function recovery. The experimental results showed that 540 mg/L and 810 mg/L of shachong-shuang caused low death rates to the wolf spider, which are 12.63% and 27.57%, respectively, but had a great impact on its predtion function, which decreased 65.41% and 81.3%, respectively; 100 mg/L of methanidophos treatment showed 49.8% of death rate and 68.56% in the decrease of function. These two insecticides showed different affecting mechanisms, the later had higher lethal toxicity and shorter duration of predation function recovery. For the third insecticide, buprofezin, both the lethal effect and function decrease of the spider could be ignored. The function recovery of the wolf spider needed about 7d after shachong-shuan and me-thanidophos treatments. Moreover, the result of field experiment indicated that application of methanidophos would cause resurgence of planthoppers due to the decline of the function of natural enemies.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Chinese)
Database assignments for author(s): Jin-Cai Wu

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
health/environmental effects of pesticides
Research topic(s) for beneficials or antagonists:
resistance to pesticides

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Nilaparvata lugens
Pirata subpiraticus (predator)	Nilaparvata lugens