稻田养蟹同稻田养鱼一样,可达到蟹稻互利,增产增收的目的,但稻的病虫害须施用农药防治,施药不当会对蟹的生长产生不同程度的影响。河蟹,尤其是蟹苗对农药、化肥的毒性比较敏感。试验表明,50%乳剂马拉松、95%晶体敌百虫对蟹苗的毒性很强,60%粉剂乐果次之,40%乳剂稻瘟净、20%粉剂稻脚青的毒性较弱。在水温19—21℃条件下,上述四种农药在水中的浓度依次达到0.05、0.02、0.5、1.9ppm以上时,均可引起蟹苗的大批死亡。所以稻田养蟹施农药必须注意以下几点: 1.施药时间:一般要求在下午4时后施药,因为随着温度的升高,农药的挥发性增大,对蟹苗的毒性也 Catch rice in rice paddies, like fish in rice paddies, can achieve the goal of mutual benefit and increase yield and income for crab rice, but pests and diseases of rice should be controlled by pesticides. Improper spraying can have different impacts on the growth of crabs. Crabs, especially crabs, are more toxic to pesticides and fertilizers. The results showed that 50% emulsion marathon and 95% crystal trichlorfon had strong toxicity to crab seedlings, followed by 60% powder dimethoate, 40% emulsion rice blast and 20% powder rice tortoise. Under the conditions of water temperature 19-21 ℃, the above four kinds of pesticides in water concentration in order to reach 0.05,0.02,0.5,1.9ppm or more, can cause a large number of deaths of crabs. Therefore, farmers should pay attention to the following aspects of crab farming pesticides: 1. Application time: the general requirements in the afternoon after 4 pm application, because as the temperature increases, pesticide volatility increases, the toxicity of crab