ORNAMENTALSAND
TURF
ORNAMENTALS
The information and recommendations in this newsletter are applicable to North Carolina and may not apply in other areas.
This is the time of year when the lesser canna leafroller is most abundant. It is a small caterpillar related to the European corn borer, pickleworm, coneworms, sod webworms and others. The lesser canna leafroller overwinters as larvae in the leaves and stems of canna, and the moths emerge to mate and lay eggs after the new growth emerges in spring. When the larvae hatch, they feed within the new, rolled leaves. Older larvae can actually tie the edges of older leaves together and roll the leaf back up! The lesser canna leafroller is evidently not cannibalistic as several caterpillars can be found feeding inside one rolled leaf. The lesser canna leafroller caterpillars only feed on the upper epidermis and mesophyl. If not managed, lesser canna leafrollers may completely destroy the aesthetic value of cannas. One mistake that canna growers make is to leave the old dead growth on the canna bed as a mulch. Canna seems to be the only host plant for this pest, so that if the plants are located somewhat remotely from other cannas it may be possible to drastically reduce the lesser canna leafrollers just by carefully removing all dead leaves and stems in the fall after the frost has killed the plants. It is possible to eradicate this pest by using Orthene as a spray several times perhaps at ten-day intervals. The Bacillus thuringiensis insecticides are also effective for this pest. Spray the dilute pesticide mixture directly downward into the rolled leaves so that the pesticide can soak into the shelter around the caterpillars. Also pick up and destroy all of the dead tops from the cannas this winter after frost.
Chinch bugs are small (about one sixth of an inch), slender insects with black and white markings. This bug is a severe pest of St. Augustinegrass in North Carolina. It also attacks centipedegrass. Chinch bugs cause yellowish spots in lawns that rapidly turn into brown, dead areas. Most of the damage is caused by the young, bright red nymphs. Chinch bugs seem to be worse in lawns that have a layer of thatch. Good thatch management helps not only by making the lawn less attractive to the bugs, but it also makes it easier for the pesticide to reach the chinch bugs when they are applied. Astro, diazinon, Dursban, Mavrik, Mocap, Oftanol, Sevin, Tempo 2 and Triumph are labeled for chinch bug management. It helps to water the lawn before treating, but not afterward for two days. However the label directions should be followed for whatever pesticide is used. Dursban or diazinon are good choices for the homeowner. There is additional information on chinch bugs in AG-268, Insect and other Pests Associated with Turf. This Extension publication should be available in the county Extension centers in North Carolina.
Because fall webworm damage accrues over the summer, fall webworms usually cause little long-term health damage to the trees they defoliate unless the trees are completely defoliated year after year. At any one location, the populations of fall webworms wax and wane so that they are conspicuous and damaging for a year or two and then the populations seem to disappear. They overwinter as pupae in cocoons in the litter. White moths emerge to mate and lay 350 to 900 eggs on the lower leaf surface. The hairy caterpillars spin the webs as they feed. There are two generations of caterpillars each year. Bacillus thuringiensis, bendiocarb, Dursban, diazinon, Orthene, Dibrom, Imidan, and Talstar are specifically labeled for fall webworm control. Available in the county Extension centers in North Carolina is Ornamentals and Turf Insect Note No. 46 which contains information on the biology and control of this pest.
Fall armyworms continue to be a serious threat to turfgrass, particularly bermudagrass. This threat will most likely continue into the fall as this pest can seriously damage overseedings in bermudagrass. This caterpillar does most of the damage during the last few days of its life as a caterpillar. The key to effective management is finding the caterpillars when they are still small. This is best accomplished by using a soapy water flush (2 ounces of liquid dishwashing detergent in 2 gallons of water, poured over an area equivalent to one square yard). Watch the area carefully for 3 to 5 minutes. Any fall armyworms present will wiggle to the surface.
Chinch bugs are still a threat on St. Augustinegrass, twolined
spittlebugs are a threat on a variety of grasses, and white grubs
are the most damaging at this time of year. If you plan to treat
with insecticide for grubs, do it soon because the window for
effective treatment is rapidly closing.
Web page last updated on September 8, 1998 by Stephen J. Toth, Jr..
