Identifying Landscape Pests

By Ashley Harbaugh, LC/dbm

Integrated pest management, or IPM, is an approach to pest control that utilizes regular monitoring to determine if and when treatments are needed and employs physical, mechanical, cultural, biological, and educational tactics to keep pest numbers low enough to prevent unacceptable damage or annoyance. The goal of IPM is to mitigate pest damage while protecting human health, the environment, and economic viability.

Spring brings out all sorts of little critters, particularly pests. Learning how to identify and treat these troublesome insects will save time, money, and your landscape.

With spring, green living things come back to life. But unfortunately, with all the green that comes back, the bugs that eat it come back too. Here are some common landscape pests that come out in the spring, and treatment options that landscapers can use against them.

Integrated Pest Management

Taking a long-term approach to pest prevention is important for the continued health and beauty of a landscape. A method that combines both a long-term view with environmental accountability is Integrated Pest Management (IPM). This approach relies on combining biological, cultural, physical and chemical tools that minimize economic, health and environmental risks.

The first step of an IPM program is to set an action threshold, a point at which pest populations or environmental conditions indicate that pest control action must be taken. Sighting a single pest does not always mean control is needed, but it?EUR??,,????'?????<

After determining an action threshold, accurately identify and monitor all pests so that appropriate control decisions can be made in conjunction with action thresholds. As a first line of pest control, IPM programs work to manage the crop, lawn, or indoor space to prevent pests from becoming a threat. Once monitoring, identification, and action thresholds indicate that pest control is required, and preventive methods are no longer effective or available, IPM programs then evaluate the proper control method both for effectiveness and risk.

When pest control is required, effective, less risky pest controls are chosen first, including highly targeted chemicals, such as pheromones to disrupt pest mating, or mechanical control, such as trapping or weeding. If the less risky controls are not working, however, then additional pest control methods are employed, such as targeted spraying of pesticides. Broadcast spraying of non-specific pesticides is a last resort.

Lawn Pests

Since the lawn is usually the focal point of a landscape, finding out which pests are wreaking havoc on it is crucial for treatment. Landscape pests can create severe damage to lawns and, if left untreated, can even kill them.

The chinch bug inserts its mouthparts into the grass, sucks out the juices, and releases a toxin into the plant while it sucks. This feeding causes yellowish to brownish patches in the turf. This pest is most damaging to open, sunny areas in the yard, and seldom attacks dense, shady patches. In many instances, chemical control of chinch bugs is not necessary. Lawns that receive adequate amounts of water throughout the summer are able to tolerate relatively high populations of chinch bugs without sustaining damage. Thatch removal is also important for eliminating favorable chinch bug conditions. If the area has habitual problems with this pest, however, it is best to apply pesticides containing bifenthrin or cyfluthrin.

Above: Chinch bug, Blissus sp. - Below: Chinch bugs are most damaging to St. Augustine grass, but they also attack zoysia, Bermuda, and centipede grasses. They have piercing-sucking mouthparts and they feed on the lower leaf sheath and crown area of the plant. Adult chinch bugs are about 1/5 of an inch long and black with white wings folded over their backs. The insect mates early in the season when the temperature reaches 70 degrees Fahrenheit. The female lays eggs on roots, stems, leaves, leaf sheaths or crevices in nodes and other protected places. Eggs are laid over a two to three week period, with one female laying as many as 500 eggs.

The caterpillar stage is when the cutworm damages turfgrass, and they seem to be most apparent in turf areas maintained at very low mowing heights. The caterpillars eat off the grass plants just above the ground, so cutworm damage on turf looks like small pock marks (or ball marks on a putting green). Cutworms are relatively susceptible to several insecticides, such as carbaryl and permethrin, and the key to successful control is to apply an insecticide when the caterpillars are still very small. Because cutworms are nocturnal, traditional insecticide applications should be made as late in the day as possible, which will ensure that the insecticide is as ?EUR??,,????'?????<

Above: Cutworm, Agrotis, Amathes, Peridroma, Prodenia spp. - Below: Cutworms can be destructive insects, particularly on golf courses and other highly manicured turf areas. Each cutworm species differs slightly from the others in details of habits and appearance, but their life histories are generally similar. Most cutworm caterpillars are about two inches in length and have a background color of dull gray or brown, but they usually have some stripes of brighter or sometimes darker colors. Adults are dull-colored moths with a wingspan of one to two inches. Adults and larvae are nocturnal and hide during the day, but may also become active on cloudy days. Cutworms overwinter in the soil either as pupae or mature larvae, and in the spring the hibernating larvae pupate.

The spittlebug gets its name from the white, frothy spittlemass it secretes that provides it protection. Both adults and nymphs suck juice from the grass with their piercing-sucking mouthparts, which leads to weakened, stressed grass that may turn yellow and then brown. In addition to feeding damage, the spittlemasses themselves give the turf an unsightly appearance. Heavy infestations of two-lined spittlebugs can produce so much spittle that the lawn actually squishes when walked upon. Numerous insecticides, such as imidicloprid, carbaryl, and acephate, are labeled to control spittlebugs on turf, and if properly applied most perform well.

Above: Two-lined spittlebug, Prosapia bicincta - Below: One of the common spittlebug species that damages turfgrass is the two-lined spittlebug. Two-lined spittlebug adults are black with two orange transverse stripes across their wings, and are about 1/4 inch long. Eggs overwinter in grass stems, behind the leaf sheath, in plant debris and other protected areas. The nymphs hatch in the spring and begin feeding, usually on lower parts of the grass plants where the humidity is high. On hot, sunny days, nymphs may penetrate even deeper into the turf.

Tree Pests

Maintaining healthy, productive trees means knowing about common tree pests. Surveying yards regularly helps identify problems at an early stage and take care of prevention quickly.

The ALB generally favors maple, but infestations also occur in horsechestnuts, poplars, willows, elms, mulberries and black locusts. The beetle chews its way into the tree to lay eggs, which then produce larvae that tunnel deep under the bark and feed on living tree tissue. This feeding effectively cuts off the tree?EUR??,,????'?????<

Above: Asian Longhorned Beetle, Anoplophora glabripennis - Below: The Asian Longhorned Beetle (ALB) is a pest threatening a wide variety of hardwood trees in North America. Adults are 3/4 to 1 1/4 inches long, with a jet-black body and mottled white spots on the back. The long antennae are 1 1/2 to 2 1/2 times the body length with distinctive black and white bands on each segment. Adults can be seen from late spring to fall, depending on the climate.

When the caterpillar eggs hatch in early spring, the young caterpillars gather in a fork in the branches and construct a web-like tent. The tents are used as shelter by the caterpillars when they are not feeding on the leaves of nearby branches. Removal and destruction of egg masses during winter greatly reduces the problem next spring, and the tents can also be removed by hand. Some contact or ingestion pesticides work on the caterpillar, and young larvae may be treated by applying Bacillus thuringiensis var kurstaki, or Bt, to the foliage of infested trees.

Above: Eastern tent caterpillar, Malacosoma americanum - Below: The eastern tent caterpillar can be a serious pest of deciduous shade trees. The caterpillar overwinters as an egg within an egg mass of 150 to 400 eggs, and it hatches around early March. Larvae vary in size from 3/8 inch upon hatching to 2 inches long when fully grown, and are primarily brown and thinly covered with light brown hairs. A white stripe on the back is bordered with reddish-brown stripes and a row of oval blue spots. The adult moths are brown with a wingspan of about 1 3/4 inch. Two narrow, lighter-colored bands may appear on the first pair of wings.

Tree damage is caused by the insect larvae, or caterpillars, which emerge from their eggs beginning in early spring and continuing through mid-May. The larvae move to the leaves of trees and begin to eat, mostly at night. During daylight hours, larvae generally seek shade from the sun but feeding can occur in daytime in heavy infestations. Feeding continues until mid-June or early July when the caterpillar enters the pupal stage and emerges as a moth. Depending on the degree of infestation, tree damage ranges from light to almost complete defoliation. Continuing attacks can fatally weaken a tree or leave it vulnerable to other insects or disease. To thwart this pest, use barrier bands to prevent larvae from crawling up tree trunks, and if infestation is extremely heavy, apply a pesticide with carbaryl, diflubenzuron, or acephate.

Above: Gypsy moth, Lymantria dispar - Below: Gypsy moth caterpillars change appearance as they grow. Young caterpillars are black or brown and about 1/4 inch in length, and as they grow, bumps develop on their backs along with coarse, black hairs. Each of the 11 sections of a developed caterpillar will have two colored spots: the first five pairs are blue, and the last six are red. Mature caterpillars can be as long as 2 1/2 inches. Gypsy moths are seen only in mid-summer. Males are grayish brown and can fly; females are larger, whitish with black marks and cannot fly.

For more information on other insects that might be invading your area, check out www.landscapeonline.com for a variety of pest articles.

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