Venkateswara Rao J, Parvathi K, Kavitha P, Jakka N M, Pallela R
Toxicology Unit, Biology Division, Indian Institute of Chemical Technology, Hyderabad - 500 007, India.
Pest Manag Sci. 2005 Apr;61(4):417-21. doi: 10.1002/ps.986.
The acute toxicity of chlorpyrifos and monocrotophos to subterranean termites, Odontotermes obesus (Rambur), has been studied by a paper contact method. The LC50 values for chlorpyrifos and monocrotophos were 0.046 and 0.148 microg cm(-2), respectively. Chlorpyrifos was 3.22-fold more toxic than monocrotophos. The effect of the pesticides on locomotor behaviour (velocity) and head acetylcholinesterase (AChE: EC 3.1.1.7) activity was estimated in LC50-exposed termites at intervals of 4, 8, 12, 16, 20 and 24 h. Chlorpyrifos- and monocrotophos-treated termites showed, respectively, 97 and 88% reduction in locomotor behaviour (velocity) after 24 h. At all time intervals the chlorpyrifos-treated termites exhibited more AChE inhibition and showed greater distorted behaviour than those exposed to monocrotophos. In vitro studies indicated that the I50 value (50% inhibition) for chlorpyrifos against AChE was 8.75 times that of monocrotophos.
采用药纸接触法研究了毒死蜱和久效磷对地下白蚁（黑翅土白蚁）的急性毒性。毒死蜱和久效磷的半数致死浓度（LC50）值分别为0.046和0.148微克/平方厘米。毒死蜱的毒性是久效磷的3.22倍。以LC50浓度暴露白蚁，每隔4、8、12、16、20和24小时评估农药对其运动行为（速度）和头部乙酰胆碱酯酶（AChE：EC 3.1.1.7）活性的影响。24小时后，经毒死蜱和久效磷处理的白蚁运动行为（速度）分别降低了97%和88%。在所有时间间隔，经毒死蜱处理的白蚁表现出更强的乙酰胆碱酯酶抑制作用，且行为扭曲程度比经久效磷处理的白蚁更大。体外研究表明，毒死蜱对乙酰胆碱酯酶的半数抑制浓度（I50）值是久效磷的8.75倍。
