Diamondback moth

The diamondback moth (Plutella xylostella), sometimes called cabbage moth, is a European moth believed to originate in the Mediterranean region that has since spread worldwide. The moth has a short life cycle (14 days at 25°C), highly fecund and capable of migrating long distances. It is one of the most important pests of cole crops in the world and will usually only feed on plants that produce glucosinolates. However, not all of these plants are equally useful as hosts to the moth; there has been some discussion of using wintercress as a buffer plant around agricultural fields as diamondback moths are highly attracted to that plant but their eggs fail to survive when oviposited on it.

The diamondback moth is most important as a pest in areas that do not experience very cold winters, as these help to kill off overwintering moths.

Symptoms
Signs are first shown as damage on the underside of leaves between leaf tissues. Later; feeding will show as holes in leaves, or holes in the underside leaving a thin membrane on the top-side. Damage only between veins. Seedlings have growing tips eaten and appear stunted.

Treatment
Observe the plants regularly, if diamondback moth populations are increasing, then start applying the natural insecticides Bacillus thuringiensis or neem.

Clean cultivation
Diamondback moth larvae and pupae remain in plant debris so sites should be cleared of all plant debris after harvest. Keep growing sites clear of weeds.

Netting
Covering individual plants or whole beds with fine mesh netting will inhibit diamondback moths and other pests from laying their eggs on plants and reduce the need for other control methods.