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Woodelf
| | Posted on Sunday, March 02, 2003 - 02:06 pm EST : |   |
I'm not sure where to post this, but I think it's useful for us to know. I put it in my garden club newsletter and several people find these nasty things in their garden last summer and didn't know what they were until I added this to the newsletter.
Sorry if this doesn't belong here, I'm still finding my way around.
HOW DO I KEEP THE RED LILY LEAF BEETLE FROM DESTROYING MY LILIES?
The Red Lily Leaf Beetle is an insect native to Europe and Asia. This beetle has rapidly spread through New England and has 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 since 1945.
If uncontrolled, the beetle will completely defoliate and ultimately kill all true lilies such as asiatic, oriental, Easter, tiger and turk's cap lilies. It will also feed on Fritillaria, and many other plants, although the primary targets are Lilium and Fritillaria.
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 adult lays reddish-orange eggs, which hatch into particularly unpleasant 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.
The adult beetle over winters 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 will not mate and lay eggs until the next spring.
There are no known natural predators in this country, although the beetle is well under control in Europe and researchers seem confident that biological control can eventually be established here as well.
Hand-picking should be the first level of control if possible. If this is not feasible, then treatment with Neem is the next choice. Neem will repel beetles and kill young larvae, but must be applied every 5 to 7 days after the eggs hatch. Merit (imidacroprid) is a systemic insecticide, which may work if applied to the soil in early spring. Various Internet sources.
Woodelf |
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