May Harmful Creatures Such as Mosquitoes and Snakes Be Killed - Jurisprudential Answers - Miscellaneous Issues, Vol 2

Ahmed al-Hasan Response:

It is permissible to kill mosquitoes if, for example, you see that they cause the transmission of malaria. It is permissible to spray pesticides to kill insects that destroy agricultural crops, and it is permissible to kill rodents that harm crops. However, killing a harmful animal without a reason is disliked. For example, a venomous snake should not be killed if it is in the wilderness or forest and is not harming anyone. Even if a harmful snake is found near people, it is better for a specialist to capture it and move it away from where people live. But if that is difficult, there is no problem with killing it.