Pest Control for Lily Leaf Beetles

How to stop these insects from damaging your plants

Gardeners who have planted Oriental lilies may know the threat posed by the lily leaf beetle. Although a minor nuisance across Canada, these beetles can be quite problematic once they establish in an area. For new gardeners who are unfamiliar with this pest, the beetle is a shiny red insect 6-8mm long with black antenna.

Lily leaf beetle overwinters in the soil or plant debris and in the spring emerges to mate and lay eggs. One female typically lays between 200 and 300 eggs in multiple small clusters on the underside of the lily leaves. The newly hatched larvae feed on the underside of the leaf and the older larvae feed on the upper side of the leaf. The feeding most often causes defoliation of the plant. However, if the infestation is severe enough, the flowers and stem will also be eaten. By the way, daylilies are not susceptible to lily beetle damage as they are not in the lily family.

Controlling is labour-intensive if you have more than a handful of plants. The best pest control for this beetle is to destroy the eggs. Beginning in late April through to October, inspect the underside of the leaves a couple of times a week for eggs. If you find any, wash them off with a soapy towel. This will help to keep the beetle populations low. To control the adults, spray neem oil onto the tops and bottoms of the foliage. Also, pick off and destroy the beetles when you see them by putting them in a bucket of soapy water.

Do not let the lily leaf beetle stop you from enjoy this beautiful flower. With some early vigilance and a little bit of time you can keep this pest in check so you can relax and enjoy your garden.

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