You may have noticed droppings on your car, or on the sidewalk. You may have thought you heard the sound of rain on a clear day. Both of these things are caused by a caterpillar that is making its way across the state.
"When witnessing an infestation, people hear what they describe as caterpillars eating the leaves or what sounds like light rain falling. This sound is in fact, frass, pellet-like caterpillar excrement, dropping onto leaves. The frass should not be allowed to fall on valued items as staining may occur," says John Hopkins, associate professor of entomology, University of Arkansas Cooperative Extension Service.
The variable oak leaf caterpillar, Lochmaeus (Heterocampa) manteo, is a native species that occurs in deciduous forest throughout much of eastern North America. Although outbreaks have not been uncommon throughout much of its range, it has been several years since I can remember an outbreak of this magnitude in Arkansas.
Larvae of this insect feed on the foliage of a large number of deciduous trees. All species of oaks are attacked; however, white oaks are generally preferred. Infestation is commonly recorded on southern red, northern red, pin, willow, black, laurel bur, and post oaks. Exotic oaks, beech, basswood, paper birch and American elm are also attacked. Occasional hosts are walnut, black birch, hawthorn, eastern hop hornbeam, apple, box elder, and persimmon.
Parts of central Arkansas are experiencing an outbreak of the variable oak leaf caterpillar. This common insect ranges from eastern Canada to southeastern states like Arkansas and Missouri. Infestations can cover millions of acres. The heaviest damage has been seen in the Mayflower-Conway area and many reports have been received from Garland County.
Larvae feed on the foliage of deciduous trees, including all species of oak. Most damage in central Arkansas seems to be on red oaks. The larval or caterpillar stage produces a 1.5-inch long caterpillar with the overall body color varying from green to yellow and red. Two generations of the variable oak leaf caterpillar can occur in Arkansas. The first generation feeds until June or July before pupating in cocoons. Second-generation larvae feed in late August and early September. Their feeding cycle should be over now or coming to a close very soon. Leaf litter is the wintertime home to the pre-pupae cocoon until pupation occurs in spring. These pink to red pre-pupae are reputed to be an excellent trout bait.
The adult is a gray moth with a wingspan no greater than 1.75 inches. While their feeding looks quite impressive, there should be no permanent damage from it. The major damage is unsightly defoliation as the larvae eat the leaves down to the main veins. Feeding caterpillars make a mess on decks, patios and in swimming pools. Infestations normally do not last longer than two years. Normally trees are not killed. However, defoliation adds another stress factor to trees, and weakened trees are more susceptible to attack from borers and diseases.
Chemical control is not recommended for most situations. Natural control by parasites and predators may destroy as much as 90% of the eggs and larvae. By not using pesticides, these parasites and predators can develop fully and do their jobs of controlling the caterpillars.
For more information, call Jimmy Driggers at 501-623-6841 or email [email protected]
There are several 4-H clubs for Garland county youths who are 5 to 19 years old. For more information on all the fun 4-H activities that are available for youths, call Linda Bates at the Extension Service office at 623-6841 or email her at [email protected]
Master Gardener information
Master Gardener meetings are held on the third Thursday of each month at the Elks Lodge off of Section Line Road. They're open to the public and guests are welcome. For more information, call the Extension office at 623-6841 email Alex Dykes at [email protected]
Are you interested in joining an existing Extension Homemakers Club? EHC is the largest volunteer organization in the state. For information on EHC, call Alison Crane at 623-6841 or email [email protected]Society on 10/21/2019
Print Headline: What's eating my trees?