Aphids

Asian Longhorned Beetle

Forest Tent Caterpillar

Giant Tar Spot

Lecanium Scales

Viburnum Leaf Beetle

Forest Tent Caterpillar

Forest tent caterpillar has been very active this year, expanding from areas of high populations last year. Sandy Wilmot, the state Forest Health Specialist reports that they have been receiving tons of calls from forest land owners, sugarmakers and homeowners. Here is an update on their aerial spray project, and suggestions they are offering to landowners.

Forest Tent Caterpillar Update and Recommendations - June 8, 2005

General Information for the Public

• The State is done spraying for this year. Our aerial spraying was limited to privately owned sugarbushes, where we had predicted defoliation from population surveys last fall and winter.
• We do not know if there will be any aerial spraying offered by the State for next year. We are compiling names of sugarbush and forest landowners who have concerns about tree health from forest tent caterpillar defoliation, in the event that we are able to offer fall egg mass surveys or aerial spraying next year. These are larger forested areas where aerial spraying may be an option (greater than 10 acres).
• The insects will be feeding for several more weeks. They reach about 2 ½ inches long before forming a cocoon. By early July they will be done feeding for this year.
• Trees defoliated 1-2 years usually recover, even if foliage is thin. Landowners can reduce other stress on trees to help them recover.
• For landscape trees, to reduce additional stress on defoliated trees, avoid disturbance around trees such as root damage, pruning or tapping trees.
• For forest trees, postpone plans to thin or harvest trees until after the outbreak. Thinning can allow drying of soil, stressing trees. Also, by reduce the number of trees in the stand, you may get more insects on each remaining tree.
• For sugarbush trees, consider reducing the number of taps or converting to smaller spouts for next year.
• For homeowners wishing to spray trees this year, we recommend using a biological insecticide containing Bacillus thuringiensis kurstaki (Btk), which is effective against forest tent caterpillars and less toxic to the environment. Point out that it needs to be sprayed onto leaves where insects are feeding; it won’t work when sprayed directly onto nuisance caterpillars, insects have to consume leaves.

Additional information: Sevin (carbaryl) is not currently registered for use on sugar maple trees that are tapped for syrup production.

There is no complete list of arborists that are equipped to spray trees. The yellow pages have lists of tree services that can be contacted. Landowners can ask questions such as: are they insured, are they a certified arborist or have a VT Plantsman’s horticulture certificate, and do they have a professional pesticide applicator license.

Press release link: http://www.vtfpr.org/protection/for_protect_forhealth.cfm