Pesticide families in the news
Pesticides in the public eye
Neonicotinoids
This group of pesticides has recently been in the news in both Germany and Italy. They are nicotine based pesticides but, due to the chemical not attaching itself to the seed, Bee populations have dropped considerably in these areas. The chemicals in this group are: Imidacloprid, Thiamethoxam, Clothianidin and Methiocarb. We will be reviewing the status of these pesticides within The Co-operative approved list of pesticides going forward.
Organochlorines
Organochlorines are broad-spectrum insecticides, meaning they kill a large range of insects, irrespective of whether they are the target pest. They were one of the first families of chemical pesticides developed, the first, and best-known being DDT. Other members of the family include lindane, aldrin, endrin and dieldrin.
They are very persistent chemicals that are not easily broken down in soil and water, building up in the environment. They are bio-accumulative, building up in the fatty tissues of insects, birds, fish and mammals. Some are highly toxic to humans and all are carcinogenic.
Carbamates
These were developed as a replacement for DDT and the organochlorines. They are, with the exception of aldicarb, much less persistent, breaking down readily in the environment. The group includes herbicides, insecticides and fungicides. Ethylenebisdithiocarbamates include the most widely used fungicides, maneb, thiram and zineb. Their use has been questioned because of their toxicity. They are known to produce carcinogens when they break down and some have been banned in the US.
Heterocyclics
These herbicides kill any vegetation they contact and can be used to kill weeds before planting crops. They include the triazines (atrazine and simazine) and the bipyridiliums (paraquat and diquat). While most chemicals in the group have low toxicity to humans, paraquat and diquat are very toxic and there is no known antidote. Atrazine and simazine have been placed on the Government's red list regarding water supplies because they can cause cancer and are often found in water supplies, having run off agricultural land into rivers.
Organophosphates
This group of insecticides was again introduced to replace the more persistent organochlorines. They include parathion, dichlorvos and dimethoate. Most do not persist long in the environment. Organophosphates were originally developed as nerve gases during the war. Those used as pesticides are very toxic to insects but not as toxic to humans. The group is very toxic to fish, earthworms and bees. A controversial use of organophosphates is for sheep dips, where there is concern they are the cause of certain health problems in farmers.
Pyrethroids/Synthetic Pyrethrum
Synthetic forms of the natural pesticide pyrethrum have been made. They include allethrin, resmethrin and permethrin. They are non-selective insecticides, killing insects other than the target pest. They are particularly dangerous to bees. They are extremely toxic to fish but most are safe to humans.
Pesticides banned by The Co-operative