Lace Bugs- Nymphs will be feeding on underside of andromeda, azalea, rhododendron and other evergreen leaves causing loss of plant vigor. Drench plant thoroughly with insecticidal soap and/or neem.

Scales are sucking insects with tube-like mouth-parts they insert into the leaves to extract the nutrient rich sap found within.

Scales too numerous to name individually will become active in May with the rise in temperature and GDD 30 – 150. Now is a good time to treat plants that may have been damaged by this pest in the past. Drench them with a horticultural oil or insecticidal soap. This will help to control the over-wintering scales (adult females) before they birth the next generation of crawlers later in the season.

Gypsy Moth caterpillars will be active as soon as the GDD count hits 80-100. By all projections, that should happen around mid-May 8-10. The Gypsy moth is a generalist and will attack almost any shade tree and several evergreens such as pine and spruce. To manage small caterpillars, use Bt in the early going before switching to spinosad (Jack’s Dead Bug Brew) as the caterpillars get larger in size

Eastern Tent Caterpillar caterpillars will be active as soon as the GDD count hits 80-100. By all projections, that should happen around Mid-May  The ETC is host selective and only a threat to Black cherry, Malus and Prunus species.  To manage small caterpillars, use Bt in the early going before switching to spinosad (Jack’s Dead Bug Brew) as the caterpillars get larger in size

Winter moth caterpillars started hatching from eggs in early April. But their siting has been sporadic and their numbers extremely low so far this spring.  Apply Bt for good control

Hemlock Woolly Adelgid– Newly emerged crawlers of this insect pest are now searching for preferred feeding sites at the base of hemlock needles.  As they search, they remain vulnerable to controlling measures.  This window of control coincides with the calendar period mid to late July or when the Golden Raintree ( Kolreuteria paniculata) is actually blooming.   An application of horticultural oil (summer rate), insecticidal soap, or a registered pesticide will be effective as long as crawlers are active.

Look for cotton swab-like cushions at the base of needles on hemlock. These are the female ovisacs of the Hemlock Wooly Adelgid (HWA).

Japanese Beetle adults (1/2″ long, oval, metallic green body) will be feeding on tender leaves of most shade trees, roses and assorted shrubs from now until mid-August. Heavy infestations may lead to serious defoliation. Adult feeding is difficult to control. Weekly sprays in July of systemic insecticides such as imidacloprid (Bayer Advanced Complete Insect Killer) will provide some protection. 

1. Using disease resistant plants
2. Disposing of shedding leaves in fall
3. Improving air circulation inside the canopy by pruning unnecessary foliage
4. Cutting back to healthy tissue should disease symptoms occur.

Two Spotted Spider Mite (honeylocust, spruce, azalea), Andromeda Lace Bug (azalea, rhododendron, andromeda), and Japanese beetle. Flecking, stippling and yellowing are the foliage damage symptoms of the first two. Treat them with horticultural oil or insecticidal soap. The latter will skeletonize the leaves. Limit damage by applying Sevin to host plants.

Asian Long-horned Beetle – August is also the peak month for adult ALB activity. Be familiar with the damage that they cause and how to distinguish the ALB adult beetle from the look-a-like native insects ( www.na.fs.fed.us/fhp/alb/. Report any potential finds to the local authorities at 866-702-9938.

Peachtree Borer is a destructive pest of primarily Prunus species (peach, plum, cherry, etc.,). The adult (1″ clearwing moth with purplish black luster) will be actively laying eggs at the base of the trunk of susceptible hosts. Larvae will soon hatch to mine under the bark. Inspect lower trunks for wet spots or oozing. These are early signs of larval injury which can eventually lead to girdling of the stem and death of the plant. Treat trunks with residual pesticides such as Sevin nor permethrin. Also, avoid piling mulch against the trunk- it attracts egg-laying by this pest.

White Pine Weevil damage is now showing up as flagging leaders on White pine, spruce and other needled conifers. Cut out and destroy injured leaders. Next year apply an insecticide in spring after temperatures consistently reach 50 ˚F.

Fall Webworm is active now. Look for protective webbing on terminal ends of shade trees and other woody ornamentals. Remove webbing with hand pruning tools; Treat high level infestations with application of Spinosad (Jack’s Dead Brew Spray).

Orange colored walnut size balls are actually the spore emitting vessel of the fungus causing Cedar Apple Rust (CAR). This fungal disease attacks Malus species (apple, crabapple, etc.) and junipers (Juniperus species). Cool, wet weather actually influences disease outbreaks. The spore balls sometimes “grow” long, gelatinous tendrils. They emit spores infect Malus leaves, causing them to discolor and shed prematurely. Later, more spores will be produced by the apple to re-infect the juniper, keeping the infection cycle going. The walnut-like object in the picture is a dried down version of the gelatinous fungus. The best way to control this disease is to plant disease resistant apple trees and to NOT plant red cedar where apples are present.

SLF was discovered attacking trees and shrubs along Route 7 in Smithfield, RI in late August 2022.   Other infestations have since been found in Lincoln and North Providence. RIDEM has been using the USDA approved pesticide Bifenfrin to kill adults at known infested sites. The spraying started in September and continued through the first week of November. The goal is to contain the spread of this lethal pest as much as possible. To learn more about SLF, visit www.dem.ri.gov/agriculture/caps-program-pests.