CPB: description, vulnerable crops and treatments

Like codling moth and whiteflies, Colorado potato beetles don't like the cold. In winter, they hibernate deep in the soil. When the temperature reaches ten degrees, the insects emerge from hibernation.

They then attack crops to feed. Their preferred food? The leaves of solanaceous plants. Potato leaves are their favorite. But they also attack tomatoes and eggplants. In the event of a large-scale invasion, the reduction or even disappearance of foliage prevents vegetables from developing.

In April, as temperatures warm up, the adults leave their shelters. In May, they lay orange eggs on the inside of leaves. They lay up to 30 eggs at a time. The larvae hatch after a week and become adults in July. In milder regions, two generations can occur in a single season.

Beetles fly several hundred kilometers in search of food. An adult devours up to 120 cm² of foliage in a month. One-week-old larvae gobble up 40 cm² of leaves.

The presence of adult beetles can be observed directly on plants. Their black excrement can also be seen on the leaf blades.

But it's on the foliage that the insects' attack is most noticeable. Leaf edges are eaten away. Stems and tubers are sometimes hit. Plant growth is slowed and harvests reduced.

Beetles are suspected of spreading diseases such as brown rot and ring rot.

Several actions are effective against the Colorado potato beetle. First of all, crop rotation is recommended.

Plant associations help protect crops. For example, plant chives, garlic and eggplants next to your potatoes.

Check the underside of the leaves of your plants to make sure your garden isn't overrun by CPB. If you find any adults, eggs or larvae, pick them up and destroy them.

But when the invasion proves too great to eradicate manually, spray with a natural insecticide, such as nettle manure or a pyrethrin-based solution.