Pest News for Week of June 3rd

ORNAMENTALS AND TURF

From: Steve Frank, Extension Entomologist

Hawthorn and Azalea Lacebugs

Azalea and hawthorn lacebugs started hatching last week. Now we see a mix of adults and nymphs. Hawthorn lacebugs feed on pyracantha, serviceberry, and cotoneaster. Azalea lacebugs feed primarily on azaleas. Both cause stippling damage visible on the top of leaves and leave fecal spots on the bottom of leaves. For more information on lacebug management, see Ornamental and Turf Insect Information ENT/ort-39 at http://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/ort039e/ort039e.htm. Imidacloprid will kill both pests, but should not be used on plants that are flowering or that will flower soon due to negative effects on pollinators.   

(http://www.xerces.org/wp-content/uploads/2012/03/Are-Neonicotinoids-Killing-Bees_Xerces-Society1.pdf).

Woolly Apple Aphids

This week we noticed woolly apple aphid infestations on pyracantha bushes around campus. These aphids produce cottony fluff along the branches. When you brush away the fluff (really it is wax the aphids produce) you will see hundreds of pink or grey aphids crawling around. Woolly apple aphids have been out for a month or so, but are becoming very noticeable now. Infestations for multiple years produce large leafless patches on bushes. The aphids cause galls to form on branches and branches become black from sooty mold. Soap or oil should provide some control. Additional aphid management information: http://www.ces.ncsu.edu/depts/ent/notes/O&T/flowers/note38/note38.html

Flea Beetles

Redheaded flea beetles, Systena frontalis, have become a serious pest of nursery stock over the past several years. They are an especially damaging pest because they feed on roots and leaves. They overwinter as eggs in the soil. Larvae hatch in spring and begin feeding on roots. The larvae are elongate and creamy-white. Heavy infestations may reduce root mass or girdle plants. Adult redheaded flea beetles are small, shiny black, beetles with reddish to dark colored head and long antennae. They are about 1/16 of an inch long and, as the name suggests, jump when they are approached. There are at least two generations in Delaware and may be more in North Carolina.

We found adults and adult feeding damage this week. The favored hosts are Itea, hydrangea, forsythia, and knockout roses. Adult management has been frustrating for growers who find that even frequent insecticide applications do not reduce adult abundance and damage to acceptable levels. Part of this has to do with not controlling larvae since even if you kill all the adults present in a crop (which you won’t) more adults are emerging from the soil every day. Research thus far in Delaware and grower reports indicate that Talstar, Sarfari, and Flagship provide good efficacy as foliar applications, but do not have long residual activity.

Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by North Carolina State University, North Carolina A&T State University or North Carolina Cooperative Extension nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact an agent of North Carolina Cooperative Extension.

For more information contact the commercial horticulture agent at your local Cooperative Extension Center.