Residents of Cleburne County are standing up and taking notice of the caterpillar infestation. Many have commented on the excessive worm droppings on driveways, vehicles, and porches. One resident of Drasco mentioned that her tree is covered with butterflies as a result of these caterpillars morphing. In light of the increasing awareness of the infestation and its cause, The Sun-Times is republishing this information from the Arkansas Forestry Service. We asked our Facebook followers if they have been affected by the infestation. To see their some of their responses, check out our Facebook page
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 cause by a caterpillar that is making its way across the state.
Jim Northum, Arkansas Forestry Commission Forest Health Specialist, said parts of central Arkansas are experiencing an outbreak of the variable oakleaf caterpillar (Heterocampa manteo). This common insect ranges from Eastern Canada to southeastern states like Arkansas and Missouri. Infestations can cover millions of acres. Northum said the heaviest damage has been seen in the Mayflower-Conway area and many reports have been received from West Little Rock.
Fully grown larva are 1 ½ inches long and vary in color from green to yellow with a pink or dark red stripe on the back depending on population. If the caterpillar population is low, they are usually pale green while high populations have red stripes as shown to the right.
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 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. Falling frass sounds like sleet peppering in dry leaves. Infestations normally do not last longer than two years. Normally trees are not killed. However, defoliation adds another stress factor to trees already stressed by the past two dry summers. Weakened trees are more susceptible to attack from borers and diseases.
Northum said two generations 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. 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.
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.
Page 2 of 2 - For more information contact your local county forester. A list of county foresters can be found at http://forestry.arkansas.gov/contactUs/Pages/WhoDoICall.aspx.