Each year homeowners spend a great deal of time and money to establish and maintain attractive lawns only to see their efforts hampered or even nullified by pests. These pests are by no means found in every lawn, but they do occur almost every season somewhere in the state. The following information is a guide to help the homeowner recognize some of the common lawns pests. It is also intended to be used in conjunction with the Lawn Insect Pest Control leaflet, number 84-22.
White grubs are probably the most serious pests of Connecticut lawns. They are the larvae or immature stages of several species of scarab beetles. The most important in our state are the Japanese beetle, the Asiatic garden beetle, the Oriental beetle and the European chafer. The grubs of these beetles are all similar in form; they have a whitish body with a brown head and, they usually lie in a C-shaped or curled position in the soil.
Adults emerge from the ground in late spring to early summer, mate and lay eggs in lawns. Grubs soon hatch from these eggs. In mild weather they live one to three inches below the surface of the lawn and feed on grass roots. In the winter they move deeper, as the surface soil freezes. In the early spring they move up, as the soil warms, to feed and to complete their development. The grubs pupate to adults and emerge from the ground in late spring and early summer. Japanese beetles will often continue to emerge from the ground over a two- to three-month period. Most species complete their development in a year while some may require two or three years.
Grub injury causes the turf to turn brown in large irregular patches that can be pulled up and rolled back like a carpet, usually exposing the grubs.
These are one of the most important pests of lawns, especially in the warmer parts of the state. These sucking insects are only about 1/6 of an inch long when fully grown. The nymphs or immatures are pinkish, reddish or brownish in color with white bands across their backs and range in size from 1/20 of an inch up to the adult size. Adults are black with pearly-white wings.
During the winter the adults hibernate in lawns, under fallen leaves and other protected places. In the spring, adults migrate to lawns and lay their eggs at the base of grass plants. The eggs hatch into tiny nymphs in about a week. Most of the damage is caused by nymphs which suck the plant sap from the grass stems. Damage first appears as small yellow or brown areas that increase in size and coalesce as the injury progresses.
The chinch bug requires 30 to 40 days to complete development. There are at least three generations a year in Connecticut. These generations tend to overlap, so it is possible to find all stages of the insect present at any given time during the summer. Hot, dry weather and sunny locations favor chinch bug development.
To check your lawn for the presence of chinch bugs, select a sunny spot where the grass is beginning to turn yellow. Pick an area where the yellow grass is along the edge of healthy green grass. Cut out both ends of a large tin can. Push one end of the can two or three inches into the soil at the selected spot and fill it with soapy water. If chinch bugs are present, they will float to the surface in less than five minutes.
chinch bug photos
Sod webworms are the larvae or caterpillars of small whitish or gray moths. The larvae are light brown, usually spotted, 1/2 to 3/4 of an inch long when fully grown, and live in silk-lined tubes just below the surface of the soil. They stay in the tubes during the day and come out to feed at night or on rainy days. The larvae eat the grass at the soil level, and the injury first appears as small brown spots in the lawn. As the injury becomes more severe, the lawn has irregular and ragged growth patches where the grass is of uneven heights. Active caterpillars can be found in such spots.
The webworm moths are most active at dusk and may be seen flying low and slowly in a zigzag pattern over the grass, scattering eggs: There are usually two to four generations per year. The presence of a severe sod webworm infestation may be indicated by flocks of birds pecking in the lawn.
Photos: Sod Webworm Moth Sod Webworm Larva
Cutworms are the caterpillars of several species of moths that are occasionally pests of lawns. They vary in color from dull-brown to gray or nearly black and range from one to two inches in length. They usually hide in the soil during the day and feed at night. They feed on the blades of grass or cut the grass at soil level, causing injury similar to that of sod webworms.
Various species of ants live in lawns. When numerous, their mounds can cover large areas of lawn. These mounds are unsightly and often smother the surrounding areas. The tunneling of the ants can also allow the soil to dry out, which may kill patches of grass. Ants will sometimes nest around the roots of grass and kill it. They may prevent grass seed from germinating by feeding on it or by storing it in their nests. Some ants live in association with root-feeding aphids, which also injure grass. Also, ants in lawns may invade homes to forage for food and, thus, become household pests.
Earthworms are usually considered beneficial. When numerous, however, they can become pests by throwing small amounts of unsightly castings on the surface of the soil.
The American crow is a large black bird with a purplish sheen and up to 21 inches tall, can sometimes be seen scratching and pecking on a lawn. They are most likely feeding on insects, such as grasshoppers, beetles, grubs or caterpillars. Controlling the food source will eliminate their presence. Mechanical methods can be employed, such as stretching monofilament lines or audio cassette tape across the area being invaded, covering the area with a net and/or using such devices as aluminum plates on a string or balloons on a long tether.
Flocks of European starlings, a blackish bird about eight inches long, are often seen feeding on lawns. They may be eating seeds or berries but, most likely, the food is an insect, such as sod webworm or grubs. The damage is minor from the starlings, but they are indicative of the presence of serious insect pests.
Voles are small rodents about three inches long and are mainly vegetarians. The main damage to turf is caused by their runways in the sod and tunnels below ground. The meadow vole makes runways which are unsightly but will fill in during the growing season. The tunneling pine vole has been known to cause damage to turf by eating grass roots if their normal food supply of roots, tubers or bulbs is in low supply.
Skunks and racoons
Skunks and racoons can sometimes cause extensive damage to lawns if an adequate grub population exists. Skunks will usually dig golf ball size holes or smaller when removing grubs. Racoons may dig a similar size hole but will often tear sections of the sod apart in search of the grubs. Damage is usually heaviest in the spring and fall when the grubs are near the surface. As night feeders, both animals are seldom seen, but the damage is obvious. The food supply must be eliminated.
The presence of moles in the lawn is usually an indication of a white grub infestation. Moles can cause considerable injury to lawns by raising ridges of turf over their runways as they tunnel through the soil in search of food. The ridges dry out, turn brown and give the lawn an irregular pattern of brown streaks. Moles are carnivorous animals that feed on insects, especially white grubs, and on earthworms. They ordinarily do not destroy plant materials, such as roots and bulbs. Damage of this sort is usually caused by field mice that use the mole runways.
Moles require a constant food supply and cannot survive for long when it is not available. If the white grubs are controlled, the moles' major food supply is eliminated, and the danger of mole as well as mouse injury is greatly reduced.
Edmond L Marrotte, Extension Consumer Horticulturist
Originally written by: Milton Savos, Ph.D. Professor Emeritus
See other related information:
Crows and How to Minimize Their Damage
Identification and Control of Mice and Voles
Termites and Carpenter Ants
Controlling Insects and Common Pests of Lawns
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