Onion maggots feed at the base of the onion plant and can kill onion seedlings. Almost complete crop loss can occur if the seeds are not treated with insecticide. The pictures shows an untreated plot with almost no onions, compared to the neighbouring plots where the onion seed and seedlings were protected by insecticide seed treatments. The insecticides that are registered for onions are classified as 'reduced risk'. They are highly effective, even though they are applied at a very low rate per hectare.
