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Ornamentals and Turf |
Pampillid wasps (also called spider wasps) are all, or mostly black in color. They prey on spiders to feed their young. The wasp stings the spider to paralyze it. It then drags the spider to its nest in the ground. Next, the wasp lays an egg on the spider. The egg hatches into a larva and the larva consumes the spider. Scoliid wasps are dark-colored, relatively large, robust, slightly hairy insects with light yellow spots or other markings. The most common Scoliid wasp in North Carolina is Scolia dubia which may be spotted within the next few weeks. Scoliid wasps are considered beneficial insects because they help to control green June beetle grubs and grubs of other insects. They are present in North Carolina from June to October, however, they are most abundant during August. The wasps are often seen hovering a few inches above lawns in search of grubs. The female wasp digs through the soil in search of the grubs, and burrows her own tunnels or follows those made by the grubs. On locating a grub, she stings and paralyzes it. After laying her egg, the wasp larva later hatches and consumes the grub. Since these wasps rarely, if ever, sting humans, no control measures are suggested. For more information see Ornamentals and Turf Insect Note No. 12.
Are your Cannas looking ragged? Damage caused by the lesser canna leafroller, Geshna cannalis, has been building over the last few weeks. Some larvae have already pupated. This insect is active from late June until frost. It is a small caterpillar related to the European corn borer and the sod webworm. 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. One mistake that canna growers make is to leave the old dead growth on the canna bed as a mulch. As canna seems to be the only host plant for this pest, it may be possible to drastically reduce the lesser canna leafroller population just by removing dead leaves and stems in the fall after the frost has killed the plants.
When the larvae hatch, they feed within the new, rolled leaves. If not managed, lesser canna leafrollers may completely destroy the aesthetic value of cannas. Dipel, Conserve, or Orthene are recommended. Addition of a spreader-sticker will help the pesticide adhere to the waxy canna leaves. Spray the pesticide directly 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.
Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
Last modified on July 26, 2004 by Stephen J. Toth, Jr.
