From the second half of summer, onion plantings often reveal plants with gnawed, perforated feathers. These are traces of the activity of an onion rattle or an onion leaf beetle. Despite its small size, the pest is capable of causing enormous damage to the crop of onions, garlic and other crops of the onion family.
The adult onion leaf beetle is an oval-oblong beetle with a bright orange back. Each elytron of the insect is decorated with ten rows of tiny dots. His paws are colored red with black stripes at the joints of the joints, and the antennae are coal-black.
The larva of the onion rattle is light brown in color, with black dots on the sides of the body, a dark head, and legs.
Beetle females do masonry for three months – from May to July. The light yellow, smooth pest eggs are oval in shape and reach a length of about one millimeter. Over time, the eggs turn red and darken before hatching.
Each female beetle produces up to 250 eggs and places them on the backs of onion and garlic leaves. The eggs are not securely attached to the leaf surface and fly off at the slightest touch.
The larvae are in the egg for 6-10 days, then they hatch and begin to actively bite into the tissue of the feathers of onions and garlic. The offspring of the onion ratchet damages not only the leaves but also eats the stems and inflorescences of onion plants with pleasure. After that, the larvae hide in the soil for pupation (they live in the form of a pupa for another 13-21 days). Then, adult leaf beetles are born from the pupae.
In central Russia, the pest can winter both in the form of a beetle and a pupa.