Physical barriers placed around some plants control certain insects.

Collars-Three- to four-inch upright cylinders of roofing paper, plastic or metal inserted one to two inches below the soil surface prevent insects, such as cutworms, from reaching and damaging stems of plants.

Shields-Squares of carpet or tar paper fitted snugly around the stem of young cole crop seedlings will prevent maggot larva from reaching the roots.

Row Covers-Commercial spunbonded row covers or cheesecloth can be used to
exclude cabbage maggots, onion maggots, leafminers, aphids, cucumber beetles, potato beetles and European corn borers; Remember to remove the cover from insect-pollinated plants (squash, cucumbers and melons) when in bloom.

In biological control, pests are controlled by the introduction of predators, parasites or diseases. This is an area many gardeners are exploring. Some biological controls are commercially available. One of the simplest to use is Bacillus thuringiensis (B. t.), a bacterium.

Tilling under crop debris in the fall destroys the habitat for many overwintering insects and plant diseases, thereby reducing their number the following year.

Insects may be hand picked from the plant. This is one of the most practical methods, especially when the pests are large, easily seen and relatively inactive. For example, Colorado potato beetle can be controlled this way. Insects may be killed by placing them in a bucket of water containing powdered laundry detergent.

Maintain healthy plants. Horticultural practices, such as proper soil preparation, fertilization and irrigation, will maintain plant vigor and reduce insect and disease damage. Plants under stress are more apt, to be attacked or damaged. Ideal germination conditions and rapid growth enable plants to out-compete or tolerate damage. Thin young plants to avoid over-crowding and weak growth.

Properly identify what is causing the problem. Determine if the pest is a serious threat to the plant. Most garden plants can tolerate some insect feeding, and pests can be washed off after harvest. If the pest is very destructive, try to use the least disruptive method of pest control.

Injury to plants should be avoided. Cuts, bruises and spots of insect damage are often sites of disease infection. Check plants for injury and insects before purchasing and planting.

Weeds and grass often harbor insects and diseases and compete with garden plants for moisture and nutrients. Mulches can suppress weeds. Heavy rains can splash soil onto lower leaves and bring them into contact with soil-borne diseases. Mulches can reduce this soil splash. If grass clippings are used as a mulch, make sure they are dried, applied in a two-to-four-inch layer and are not from lawns recently treated with herbicides.

Select disease and insect resistant varieties of plants which are adapted to local growing conditions.

Rotate crops, when possible. Crop rotation can reduce the buildup of soil-borne diseases.

Practice proper sanitation. Remove crop residues, diseased plant materials, trash and weeds from the garden plot. Clean up crop residue as soon as harvesting is completed. Remove infected leaves immediately. Dispose of severely diseased plants before they contaminate others. Old sacks, baskets, decaying vegetables and other debris should be kept out of the garden. Weeds attract or support insect populations and harbor plant diseases that may be transmitted to plants.

One of the most effective practices to minimize disease and insect problems is to scout the garden. Early detection is helpful.

Do not smoke any tobacco products while working in the garden. After smoking outside the garden, wash hands before entering the garden. Tomato, pepper and eggplant are susceptible to a mosaic virus disease which is common in tobaccos and may be spread by hands.

Stake plants or plant them in wire cages to prevent the fruit from touching the soil and rotting.

The timing of planting and harvest can be helpful in controlling certain pests. Keep a record of dates when insect problems occur. Time planting to avoid the peak insect infestations. For example, plant squash as early as possible to avoid borers, which lay eggs in July. Planting cabbage in late May will avoid maggot infestation since few flies are active at that time. Carrots planted after June first and harvested by early September are usually not damaged by the carrot rust fly. Plant warm weather crops after the soil has warmed to avoid problems with poor seedling germination and root rots.

Traps and lures may attract insects by visual or chemical cues. Visual traps, such as yellow, sticky boards, are generally used to monitor insect populations. Lure traps, such as Japanese beetle traps, contain chemical attractants. These traps lure large numbers of pests; keep them at least thirty feet away from the garden. Electronic and ultraviolet traps are not recommended.

Watering in the morning gives plants time to dry during the day. Drip irrigation prevents the foliage from getting wet. To prevent fungal infections, leave space between plants for good air flow. Orient rows so winds will help foliage dry quickly after rain or watering. To prevent spreading diseases, stay out of the garden when plants are wet with rain or dew.

Revised and updated by Richard A. Ashley, IPM Coordinator, University of Connecticut. March 2000.

Originally published: Hort Impact, Volume-97-7 July 1997
By: Norman Gauthier, Senior Extension Educator, Fruits and Vegetables, University of Connecticut, July 1997

This information was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.

The information in this material is for educational purposes. The recommendations contained are based on the best available knowledge at the time of printing. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension system does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.All agrochemicals/pesticides listed are registered for suggested uses in accordance with federal and Connecticut state laws and regulations as of the date of printing. If the information does not agree with current labeling, follow the label instructions. The label is the law.Warning! Agrochemicals/pesticides are dangerous. Read and follow all instructions and safety precautions on labels. Carefully handle and store agrochemicals/pesticides in originally labeled containers immediately in a safe manner and place. Contact the Connecticut Department of Environmental Protection for current regulations.The user of this information assumes all risks for personal injury or property damage.Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Kirklyn M. Kerr, Director, Cooperative Extension System, The University of Connecticut, Storrs. The Connecticut Cooperative Extension System offers its programs to persons regardless of race, color, national origin, sex, age or disability and is an equal opportunity employer.