These pests can cause damage to your garden and yard. Here are some of the most common and damaging, as well as what signs to look for.
Japanese beetle
These pests hide over the winter as grubs in the soil. As the soil warms they move toward surface and feed on grass roots. They pupate in late May and hatch as adult beetles in late June. Feeding on foliage (skeletonizing of the leaf is their signature damage) continues for 30-45 days until the females lay eggs in the thatch. Grubs hatch in 10 days and begin to feed on grass roots through September.
Control can be with Bt (Bacillus Thuringiensis) early in the season. Turf application of Merit can be applied in late spring.
Bagworm
The bagworm is most recognizable by the case or bag hanging from the foliage that the caterpillars form from silk and plant debris. Eggs over-winter in the bags from the previous season and hatch in late May-early June. Feeding and development continues till mid-August. The bags continually enlarge from 1/8 inch long to 1 ½ inch at full maturity. During feeding the black shiny heads of the female stick out of the top of the bags. They feed mostly on evergreens with arborvitae and juniper being their favorite.
Control can be simply picking off the bags in early spring and discarding but not by dropping on the ground. If the infestation is heavy chemical control will be necessary because one bag can contain up to 1,000 eggs! Orthene, a systemic insecticide, is commonly available for control of bagworm but must be applied by end of June.
Spruce spider mites
These over-winter as brown eggs at base of needles. They hatch in spring with multiple over-lapping generations throughout the year. The mites suck plant juices from the needles which cause a speckled, dusty brown appearance to the foliage. Silken webs may be formed in the foliage. Use the “white paper test” to detect the presence of mites. Hold a piece of white paper under a section of suspect foliage. Tap the foliage above the paper. Move paper away from plant and take your thumb and drag it across the paper. If squish marks appear it indicates the presence of mites. They appear merely as tiny dots to the naked eye. A hand lens is required to see the actual insect which resembles a spider.
Control windows occur twice during the year. Treat with a miticide like Avid or Forbid in late May. Wait 7 days and preform the white paper test again. Re-treat if necessary. A second application is recommended in early September.
Fall web worm
This worm over-winters as a cocoon in the soil. Adult moths appear in mid to late June and deposit eggs on the undersides of leaves near the branch ends. Larvae hatch and spin webs encasing leaves at branch ends by mid to late July. They consume the leaves within the web and feed for about six weeks. By mid-September they move down to the ground and pupate in the soil and leaf litter till the following spring. In most cases, their damage does not cause health issues for the plant because the defoliation occurs late in the season when leaves normally begin to fall. The issue is mostly cosmetic due to the unsightly webs that hang onto the tree branches.
Control measures from Bt (Bacillus Thuringiensis) applied early in the season when feeding caterpillars are small or a soil drench using Bayer Advanced Tree and Shrub Insect Control to simply pruning out the affected branches (not burning out).
In the case you find one or more of these pests are destroying your yard, you may need a professional in extermination. If the cause of your garden wilting is something else, a landscaper may be able to help revive your yard with the proper maintenance. We offer seasonal landscaping, irrigation systems, hardscape and patio projects, and much more across Allentown, Wyomissing, and Lancaster.