Defoliators
> Lily Leaf Beetle
Pest: Lily Leaf Beetle (Lilioceris lilii (Scop.))
Order: Coleoptera
Family: Chrysomelidae
Host Plants:
This pest will only lay its eggs on true lilies and Fritillaria
species. Although, researchers in Rhode Island have found it feeding
on such other host plants as: Soloman’s seal (Polygonatum
sp.), Bittersweet (Solanum sp.), Potato (Solanum tuberosum),
Hollyhock (Alcea), and various Hosta species. This pest does
not attack daylilies.
The lily leaf beetle is an imported pest that attacks
all true lilies. It was first discovered in the United States in
1992 in Cambridge Massachusetts. Most likely, it arrived in a shipment
of lily bulbs from Europe. Since this time, it has spread throughout
eastern Massachusetts and is now in the central part of the state.
They are strong fliers and can also be moved from one area to another
on host plants. Both the immatures and adults are capable of causing
great harm to their host plants.
Description:
Adult Beetles are bright red and are about 1/2" in body length.
Their appearance is quite noticeable. The larvae
(immatures) are slug-like in appearance with swollen bodies and
black heads. While they feed, these larvae pile their own excrement
on their backs and thus display a rather repulsive image.
Life Cycle:
Adults over-winter in secluded, sheltered places. They emerge early
in the spring (late March into early April in Massachusetts) and
begin to forage for food and to begin seeking a mate. Adult females
lay their eggs in irregular lines on
the undersides of the foliage. These reddish-brown eggs start to
appear in April-May and hatch within 4-8 days. The young larvae
initially feed on the undersides of the foliage but can later be
seen on the upper surfaces and the buds. The larval feeding period
is the most destructive and lasts for 16-24 days. They then drop
to the soil to pupate and new adults emerge 16-22 days later and
can be seen feeding throughout the rest of the growing season. Mating
and egg-laying occurs the following spring. Each female beetle produces
250-450 eggs.
Management:
When only a small number of plants are infested, one can remove
these pests manually. However, when many susceptible plants are
attacked, applications of pesticides may be warranted. Neem products
have been shown to kill larvae (especially the very young ones)
and to deter the adults but applications may need to be administered
early in the growing season and then repeated with some regularity
(weekly) in order to achieve the desired level of effectiveness.
Chemical pesticides are available but be careful to not use these
when foraging bees are in the area and visiting flowers.
Inspect host plants carefully, at the point
of purchase, and when moving plants from one geographic area to
another to avoid inadvertently moving (or inheriting) this pest.
This fact sheet was developed
from information obtained from the University of Rhode Island.
Special thanks go to S.B. Livingston and Richard Casagrande.
Images:
| 
An adult lily leaf beetle (R. Childs)
A larva of the lily leaf beetle. Note the "slug-like" appearance
and the excrement piled on its back (R. A. Casagrande)
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Defoliators
index:
Armyworm
Asiatic Garden Beetle 
Bagworm
Cankerworms
2006
Caterpillar Update
Eastern Tent Caterpillar
Fall Webworm
Forest Tent Caterpillar
Gypsy Moth
Japanese Beetle
Larch Casebearer
Lily
Leaf Beetle -
Courtesy of URI Extension
Mimosa Webworm
Viburnum Leaf Beetle
Winter
Moth - ID & Management
UPDATED! Winter
Moth Overview
Winter
Moth Project - Biological Control in MA
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