Comparative effects of insecticides with different mechanisms of action on Chrysoperla externa （Neuroptera＂ Chrysopidae）＂ Lethal,sublethal and dose-response effects

The comprehensive knowledge that the delayed systemic and reproduction side effects can be even more deleterious than acute toxicity, has caused a shift in focus toward sublethal effects assessment on physiology and behavior of beneficial insects. In this study, we assessed the risks posed by some insecticides with different mode of action through lethal and delayed systemic sublethal effects on the pupation, adult emergence, and repro- duction of the chrysopid Chrysoperla externa （Hagen, 1861; Neuroptera： Chrysopidae）, an important predator in pest biological control. The maximum field recommended dose （MFRD） and twice （2xMFRD） for chlorantraniliprole, tebufenozide, and pyriproxyfen were harmless to C. externa. In contrast, all the tested chitin synthesis inhibitors （CSIs） were highly detrimental to the predator, despite of their lack of acute lethal toxicity. There- fore, the safety assumed by using IGRs toward beneficial insects is not valid for chrysopids. Dose-response data showed that although all CSIs have a similar mechanism of action, the relative extent of toxicity may differ （novaluron 〉 lufenuron 〉 teflubenzuron）. For CSIs, the delayed systemic effects became obvious at adult emergence, where the predicted no observable effect dose （NOED） was 1/2 048 of the MFRD for novaluron （0.085 ng/insect）, and 1/256 of the MFRD for both lufenuron （0.25 ng/insect） and teflubenzuron （0.6 ng/insect）. Finally, this work emphasized the significance of performing toxicity risk assessments with an adequate posttreatment period to avoid underestimating the toxicities of insecticides, as the acute lethal toxicity assays may not provide accurate information regarding the long-range effects of hazardous compounds.     

三种颜色诱盆在棉田的诱虫效果初步观察

在无化学诱剂的条件下,使用粉红、蓝和绿色3种诱盆对棉田昆虫进行了诱集,结果表明：粉红诱盆对红铃虫Pectinophora gossypiella(Saunders)、棉铃虫Helieoverpa armigera(Htibner)有较高的诱集能力,但对蜜蜂杀伤力大;蓝色诱盆对棉铃虫和银纹夜蛾Plusia agnata Staudinger具有较好的诱集效果,对红铃虫无诱集能力;绿色诱盆几乎无诱集能力。     

可怕的生物武器

美国纽约世界贸易大楼被炸之后 ,紧着又接连出了多起炭疽菌事件 ,因而引起全世界对生物武器的热切关注。现在让我们来聊聊生物武器。五十年代 ,笔者还是中学生时 ,就在科学杂志上看到苏联专家预言２１世纪将是生物学世纪。当时人们虽不清楚未来的生物学将是什么样子 ,可这预言总是给我们对新世纪以美好的憧憬。时间荏苒 ,２１世纪已经来到了 ,果不其然 ,新世纪伊始 ,就有两本人类基因组草图分别在两家世界权威杂志 ,英国的《自然》和美国的《科学》上同发表。人类基因组草图的绘制成功可说是生命科学进入新世纪的宣言书 ,它标志着人类跨进了…     

几种化学农药对稻田优势种蜘蛛杀伤力的研究

用５种化学农药对稻田优势种蜘蛛杀伤力的盆栽与田间进行测试。结果表明，５种化学农药对稻田４种优势种蜘蛛都有较大的杀伤力，总的杀伤率达６２．１％－９１．７％，盆栽施药比田间施药对蜘蛛的杀伤力大。田间试验结果应当比较符合实际；田间试验对照组蛛虫减退的民政部进一步说明，蜘蛛对目标害虫具有良好的控制作用，在晚稻后期，如果蛛虫比在１：５以下，用不着使用化学农药防治。