On Gardening: Inchworm, inchworm, eating up the maple tree
by Danielle Carroll
Special to The Star
Apr 08, 2012 | 4299 views |  0 comments | 6 6 recommendations | email to a friend | print
Insects are a part of life. Some we gladly welcome each year, like the ladybug beetles. When I see them in the garden, it is a great sign. I know they are voracious eaters of aphids and are there to keep the population under control. They are there to help.

Some other insects are not so welcome. Take the pesky inchworms that have recently invaded forests and residential landscapes.

There is more than one type of inchworm inching around right now. There are spring cankerworms, oak cankerworms and Linden loopers. They are all about the same size — about an inch or so long — but they vary in color.

They have been known to arrive in hordes for three to five years in a row. They may also take a break and be present in lower numbers for the next couple of years.

Inchworms are easily distinguished by the looping motion they make when they move. These types of insects arch their midsections when they move, allowing their hind prolegs to meet up with their anterior true legs. In other words, they do not have legs all along their bodies.

These inchworms are the larval stages of moths. For some species, the female moth is wingless. She walks up the trunk of a tree in late winter. The winged male moth flies to her. The female then lays eggs within the bark.

In species such as the Linden looper, the female has wings. She flies to the trees and waits on the male, before laying eggs.

The eggs hatch about the time the leaves come out. All of these caterpillars have something in common: They love to eat. When present in high numbers, you can actually hear the munching of the insects.

The diet of the cankerworms is quite diverse, but all consisting of deciduous trees. Host species attacked by Linden loopers include red and white oak, maple, elm, hickory, ash and cherry. Spring cankerworms feed on trees such as apple, beech, hickory, maple and oak.

You may first notice small holes in young leaves. As the larvae become bigger, their appetites increase, and leaves may become skeletonized — the same type of damage caused by Japanese beetles.

Along with the noise, you may also encounter the excrement of the insects, which can become quite messy.

On a positive note, the timing of leaf-eating couldn’t be better. It is very early, and defoliated trees will recover quickly. Fertilizing landscape trees can help with new growth.

The other good news: These cankerworms will not be around forever. They will eat for several weeks, then they will drop to the ground on silk strands. There, they will burrow into the ground and spin silken cocoons. They will remain there until they emerge in late winter as adults.

Controlling inchworms

It’s usually not necessary to treat large trees or woodland settings. It’s almost impossible to spray entire trees, and these large trees will recover quickly on their own.

Consider treating newly planted, young or fruit trees to avoid yield losses. One very effective treatment is to wrap trunks with sticky band early in the year, to trap the crawling adult females and the adult male visitors.

A 2 percent-3 percent dormant horticultural oil can be used as a trunk spray, and is effective on the eggs. But be careful: Trees that are not dormant (active) may incur injury. Always read the label for application rates and times.

The biological control Bt, Bacillus thuringiensis, is also effective. Again, timing is important. Bt sprays work well if applied soon after egg hatch when the larvae are small.

Conventional pesticides can also be used. Always check the label to make sure caterpillar pests and the target plants are listed.

Once populations are high and trees have been defoliated, chemicals are not that effective. Remember, trees do put out more leaves, and a lot of time control is not necessary.

Danielle Carroll is an extension agent for the Alabama Cooperative Extension System.

Gardening events

April 21: The first plant sale of the season sponsored by the Calhoun County Master Gardeners/Tree Amigos Program, 8-11 a.m. (or until all plants are sold) at Cane Creek Community Gardens at McClellan. Unusual perennials for sun and shade, trees and shrubs will be available. The sale benefits the 4H program at the Coosa Valley Attention Home. For more info, contact the Calhoun County Extension System Office, 256-237-1621.

April 24: North Alabama Rare Plant Society hosts a free lecture on “The Cream of the Crops: Top Picks for 2012,” with Scott McMahan of McMahan’s Nursery in Georgia. There will be a silent auction at 11 a.m., followed by the lecture and free lunch at noon. Plants from the nursery will be available for sale after the lecture. At First Presbyterian Church of Anniston. Reservations required. Call 256-832-2227 or 256-236-4842, or email ohatcheeusa@cableone.net or abugsy1@aol.net by April 19.

April 25: “Lunch and Learn,” a series of free gardening programs sponsored by Calhoun County Master Gardeners and the Calhoun County Commission. Held the fourth Wednesday of each month, noon-1 p.m. at Cane Creek Community Gardens at McClellan. Bring your own lunch.

April program: “Stone Structure Sites on Choccolocco Mountain” with Harry Holstein of the Jacksonville State University Archeology Department. Call 256-237-1621 for more info.

April 27: “Every Home Deserves a Garden,” a lunch and chat with legendary University of Georgia coach Vince Dooley and his wife, Barbara Dooley. 11:30 a.m. A benefit for the Anniston Museum’s future Botanical Gardens. $100 ($50 for museum members, or those who have purchased an engraved Botanical Gardens paver). For more info, contact the museum at 256-237-6766.

April 28: Jacksonville Garden Club plant sale. 8-11 a.m. in the parking lot of Dr. Terry Bonds office, 601 Pelham Road S. (Rain date May 5.)

Show us your garden!

Do you have blooms worth showing off? Mail photos of your garden, along with a brief description, to “Show Us Your Garden,” Lisa Davis, Features Editor, Anniston Star, P.O. Box 189, Anniston AL 36202. Or email ldavis@annistonstar.com (please put “Show Us Your Garden” in the subject line). We’ll publish our favorite photos in an upcoming Life section.
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On Gardening: Inchworm, inchworm, eating up the maple tree by Danielle Carroll
Special to The Star

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