Red Lily Beetle are a new pest, which sadly have decimated our lily bed in the back patch. One glorious asiatic lily which stood six feet tall in full bloom persisted despite the onslaught, but many plants failed to flower at all. What to do?
First things first – know thy enemy. These little blighters overwinter as adults in soil and other sheltered places – but not necessarily anywhere near the actual lily plants, so there’s no advantage to treating the soil around affected plants. Beetles begin to emerge on sunny days in late March onwards.
Red Lily Beetle are notable in that they can feed on other plants, but will only lay eggs and reproduce on lily plants. They lay their eggs in small batches on the underside of leaves from April to mid-summer. When the eggs hatch the larvae feed on the foliage, and then go into the soil to pupate. Adult beetles finally emerge mid-summer onwards, who also add to the feeding damage.
There is only one new generation a summer. So thankfully the young summer adults will not mate and lay eggs until the following year. The bad news is that the only effective remedy is handpicking adults off the plants. And I suppose to keep a good eye out for the eggs laid in the underside of lily leaves. Grrrrrr.