Have you noticed lately that the leaves of your Asiatic lilies are riddled with holes? You may have a
problem with the infamous red lily leaf beetle. Don’t throw your hands up in despair…there is help
for your botanical friends.
ORIGIN: The red lily leaf beetle (Lilioceris lilii) is an insect native to Europe and Asia which rapidly
spread through New England from Eastern Massachusetts and which has been also been found
in Northern New York State. The original infestation in New England was detected in 1992 in
Cambridge, Massachusetts, although the beetle has been active in the Montreal, Canada, area
DAMAGE: If uncontrolled, the beetle will completely defoliate and ultimately kill all true lilies (Lilium
species, such as Asiatic, Oriental, Easter, Tiger and Turk’s Cap lilies). It will also feed on Fritillaria
species, and many other plants, although the primary targets are Lilium and Fritillaria species.
DESCRIPTION: The adult beetle is bright scarlet red, with black legs, head, antennae and
undersurface. It is 1/4" to 3/8" long and is a strong flyer. The beetle reportedly will squeak if
squeezed gently (however, few gardeners are willing to be gentle to this beetle). The adult lays
reddish-orange eggs which hatch into particularlyunpleasant larvae, which look like 3/8" long
slugs; colored orange, brown, yellow or green with black heads. The larvae cover themselves
with their own excrement (known as a fecal shield) which apparently repels predators, including
gardeners who are generally very reluctant to handle the larvae. The larvae eventually become
fluorescent orange pupae.
LIFE CYCLE: The adult beetle overwinters in the soil or plant debris and emerges in early spring
looking for food and a mate. After mating, the female lays eggs in lines on the underside of Lilium
or Fritillaria leaves. Some damage is done by the adults at this time, but the major damage comes
when the eggs hatch into larvae in 7-10 days. The larvae voraciously consume all leaves within
reach and may then start on flower buds. This continues for 2 to 3 weeks, when the larvae then
drop into the soil and begin to pupate. In another 2 to 3 weeks the adult beetles emerge to start
eating again. This process occurs from early spring to mid-summer. Reportedly the beetles won’t
mate and lay eggs until the next spring.
CONTROL: First of all, if you’re in an infested area, avoid trading any lilies or other plants to your
friends, and carefully inspect any plants you receive.
Hand-picking should be the first level of control if possible. Constant vigilance and quick removal
and disposal of beetles, eggs and larvae can control an infestation on a small number of plants.
Make sure the critters are actually dead! If you squash them, don't leave the squashee in the
garden. Some gardeners drop them into a can of water with vegetable oil on the top.
If you suspect the beetles may be lurking around your lilies but you don't see any, carefully dig
in the top half inch of the soil - no deeper! They hide just under the surface, so be ready to get
them when they pop out.
If this isn’t feasible, then treatment with Neem oil is the next choice. Neem oil will repel beetles
and kill young larvae, but must be applied every 5 to 7 days after the eggs hatch.
and to beneficial insects and should be used with extreme caution. Carbaryl (Sevin) and
Malathion are effective on both the adult beetles and the larvae.