Onions leaves sometimes become yellowish -grey, wither and soon dry up. These damages cause larvae of onions fly (whitish, length of a body to 10 mm). The onions fly develops on an onion set and an onions-turnip. Often such plants simultaneously are damaged by "neck" rot and cauline nematode. The onions fly is extended almost everywhere. Chrysalis winter in pseudopupa in soil, the adult Onions flies eating nectar in the spring take off. Soon (in a midland in the end of May - the beginning of June) onions flies blow eggs (on some pieces) on soil near plants or between onions leaves. Approximately in a week there are white, legless larvae which get into a bulb through a bottom and eat away in it a cavity. Such bulbs rot. In the south One generation, in a midland - two, and - three in the north develops.
It is noticed that early crops suffer from Onions fly, than late less. It is necessary to exterminate sick plants in due time also.