Lily Beetle [ Lillioceris lilli ] often known as Red Lily Beetle or Scarlet Lily Beetle is a pest of Lilies and Fritillaries. Adults are red with black heads and legs. They overwinter as adults in the soil or leaf litter, not always near Lily plants. In about late March they emerge. Egg laying starts in April, athough only one generation a year is produced. The eggs are normally laid in clusters on the undersides of leaves. The adults are active from April to October.
The adult beetles feed on the plant foliage causing holes in the leaves and weakening of the plant. This leads to the production of undersized bulbs that may not even flower. They leave a black excrement on leaves and flowers . They also cover their larvae in this, which graze on leaves.
How to control and prevent Red Lily beetle
Once beetles are observed, pick them off plants and destroy. The Lily beetle has few natural predators as the larvae are covered in excrement, which puts off predators feeding on them! Currently there are no biological controls for this pest. Lily plants can build up some resistance to damage caused by the Red Lily beetle and regular applications of Calcium based products such as Calcium Boost have shown to make Lily plants more resislent to Red Lily beetle attack .
See Calcium Boost for more details