Re: lily leaf beetles
- To: perennials@mallorn.com
- Subject: Re: lily leaf beetles
- From: R* B* <s*@ici.net>
- Date: Wed, 1 Jul 1998 10:44:24 -0400 (EDT)
The following is lifted verbatim from the July 8, 1996 issue of "Hort
Notes", the UMass extension newsletter for hort professionals. Hort Notes
lifted it from "Lily Leaf Beetle" , S.B. Livingston and R. A. Casagrande,
Dept. of Plant Sciences, Univ. of Rhode Island, Kingston, RI 02881 (the
typos are mine)
LILY LEAF BEETLE
Lily Leaf Beetle (Lilioceris lilii (Scop.)), a severe pest of lilies, was
first officially sighted in the USA in the summer of 1992 in Cambridge, MA.
This European insect was also discovered near Montreal, Canada in 1945.
Most lilkely, it came to the US in a shipment of bulbs from Europe. These
bettles are strong fliers and excellent hiders. They have spread rapidily
over the greater Boston area, and can now be found 100 miles outside Boston.
Landscapers who are transplanting bulbs must be very cautious not to move
the beetles to an uninfested area.
Researchers from URI conducting a study in Waltham, MA found that lily leaf
beetles (LLB) will taste or feed lightly on many hosts: Lilium spp.,
Fritillaria spp., Polygonatum spp., Solanum dulcanum. Solanum tuberosum,
Convallaria majalis, Alcea rosea, Hosta spp., Smilax spp., Nicotiana spp.,
and other plants. However, LLBs will only lay eggs on Lilum spp. and
Fritillaria spp.; adults and larvae will only feed heavily on leaves, stems,
buds and flowers of Lilium and Fritillaria. They also found two Lilies more
resistant: L. henryi and L. speciosum 'Uchida'. These are species lilies
and both are known to be hardier and more resistant to disease; they also
bloom later in the season.
BIOLOGY The LLB adult is a striking insect with a bright scarlet body and
black legs, head antennae and undersurface. The adults are 1/4 to 3/8 inch
long, and they will squeak if you squeeze them gently; they do this to deter
predators. Adults also secrete a noxious substance from the elytra ( the
hardened front wings) and pronatum (upper surface of the thorax). Adults
lay their eggs on the underside of leaves in an irregular line. The reddish
orange eggs take from 4 to 8 days to hatch. Females lay from 250 to 450
eggs, sometimes over two growing seasons.
Larvae resemble slugs with swollen orange, brown yellowish, or even green
bodies and black heads. They are smaller than adults but tend to cause more
damage. Larvae are distinctive and repulsive in that they secrete and carry
their excrement on their backs. Younger larvae feed primarily on the
underside of leaves. Larvae feed for 16 to 24 days and pass through four
instars before entering the soil to pupate. Pupae are fluorescent orange.
New adults emerge in 16 to 22 days and feed until fall. They do not mate or
lay eggs until the emrge the following spring in March through June. LLBs
overwinter in the soil or plant debris in the garden or woods, somtimes a
distance from the host plants. Adults prefer environments that are shaded,
protected, cool and moist.
CONTROL If you have only a few plants in your garden, hand picking adults
and eggs can be effective (the researchers prefered not to handle the
larvae). The insecticides carbaryl (Sevin*) and malathion are effective on
adults and larvae. However, carbaryl is highly toxic to bees and malathion
kills many non-target insects. Neem (Turplex, Azatin EC, Margosan-O, Align,
Bioneem*) kills larvae and repels adults. It is most effective on the first
instar larvae and must be applied every 5-7 days after egg hatch. Merit was
also found to be effective.
To help researchers keep track of the beetle's distribution, please report
any sightings more than 50 miles from central Boston to S. B. Livingston or
Richard Casagrande, URI Dept. of Plant Sciences, at (401) 792-2750.
--------------
So far, I haven't seen them here (35 miles south of Boston), but I know it's
just amatter of time....Good Luck, and keep us posted.
Russ
At 10:39 06/27/98 -0400, you wrote:
>I found these last week in my garden. Actually I saw the little red bugs
>very early in the season but didn't know they were bad so left them alone.
>Anyway in the last week they have laid their disgusting muddy young on my
>lilies and eaten half the leaves. On the web I found out that Neem worked.
>Is that easy to purchase? I have been using the soap/mouthwash spray I use
>for lots of stuff and it's slowing them down. Crushing them between two
>bricks is working even better.
>
>I also read they were only in Boston and surrounding 20 mile area but I'm
>in Montreal.
>
>Any suggestions?
>
>Ann
>Zone 4
>
>---------------------------------------------------------------------
>To sign-off this list, send email to majordomo@mallorn.com with the
>message text UNSUBSCRIBE PERENNIALS
>
>
Underwood Shade Nursery 508-222-2164
'Solutions for the Shady Garden' fax 508-222-5152
PO Box 1386 shadeplant@ici.net
North Attleboro, MA 02763 catalog $2.00, refundable with the first order
zone 6
---------------------------------------------------------------------
To sign-off this list, send email to majordomo@mallorn.com with the
message text UNSUBSCRIBE PERENNIALS
