Managing Insect Pests

Several options may be used to help reduce insect pests in home gardens. These include the use of pest-resistant varieties, mechanical controls such as row covers or hand picking pests, and cultural practices including rouging out (digging up and removing) infested plants. Some are more practical than others, and success will depend in part on your willingness to work at them. Integrated pest management (IPM), an approach that uses all pest control options, is recommended. The goal of IPM is to reduce risks to the environment and human health.

One of the most important strategies in dealing with insects is to learn about their habitat, behavior, life cycle, what they feed on, and whether they are actually pests. This information will help you decide what to do. Most insects found in the garden are not pests and some are beneficial.

See Chapter 12 in Part I: Cultural Methods, of Pest Management Around the Home for cultural recommendations and troubleshooting in the home garden.

Another important aspect of IPM is deciding just how many pests or how much damage can be tolerated. For example, feeding damage to wrapper leaves on cabbage is tolerable because the leaves are discarded anyway. It is not necessary to eliminate all pests. In fact, having a few present allows natural enemies to feed and reproduce and maintain some balance between beneficial and harmful insects. Before taking a control action, be sure it is really necessary.

Pesticides may also be used as part of the pest management program but should be used only when the other options have not proven effective. Be sure to use only the amount needed and to treat only the plants that need treating. Spot treatments are effective and may be practical for home gardens. See Table 16 for pesticide options and Tables 3 and 4 for toxicity information.

The use of biorational pesticides such as Bacillus thuringiensis (Bt), a toxin produced by bacteria that kill caterpillars, is strongly encouraged. These products affect only caterpillar pests, leaving beneficial insects unharmed. Traditional chemical pesticides will control the pests but also eliminate beneficial insects that naturally help to suppress pests. Insecticidal soaps are also an alternative to some chemical pesticides and may be useful for certain pests, especially aphids, in the home garden. Diatomaceous earth, a desiccant, is sometimes used to control insects, slugs, and snails. Once it gets wet and compacted, however, it loses its effectiveness.

Before using any pesticide, check the label. Both the crop you wish to treat and the pest you are treating for must be listed on the label. If not, do not use the pesticide. Also make sure to read the label to determine how long you need to wait before harvest. Harvesting treated vegetables too soon after a pesticide application may result in excessive residue being present when consumed.

Even if a pesticide is botanical in origin it may be toxic. Some botanical insecticides are more toxic than some of the commonly available synthetic chemicals.

No matter which methods you choose, keep a record of what you did and whether it was successful. Such a record should be a great help in the future when you are faced with similar pest management decisions.

Purchase Treated Seed

Seed may come pretreated with a dusting of a fungicide. This coating helps prevent the seed from rotting in the soil before germination and can help protect the emerging seedling from damping-off. If seed rot or damping-off has been a problem in your garden, using treated seeds will help.

* Disease sanitation practices: Avoid wetting leaves when watering. Water early in the day so foliage will dry quickly. Avoid crowding; space plants to allow good air circulation. Eliminate nearby weeds, to improve air circulation. Remove any diseased or dropped leaves. At the end of the season, remove all plant tops, and dig up and remove roots.

For toxicity information, see Table 3 in Chapter 3, and Tables 4b and 4c in Chapter 4.

Also see Chapter 12 in Part I: Cultural Methods, of Pest Management Around the Home.

Table 16. Vegetable pest management Always check the pesticide label to make sure both the crop and the pest are listed, and to check for the minimum number of days to wait between application and picking the crop (“Days to Harvest”).
Plant	Pest	Some Pest Management Options
Asparagus	Asparagus beetles (common and spotted) Common asparagus beetle	Handpick and remove beetles. If needed, use carbaryl, kaolin clay (for suppression only), malathion, permethrin, pyrethrins, or spinosad.
Bean	Bean common mosaic virus	Rogue plants: remove and destroy diseased plants, along with immediately surrounding soil. Do not save seeds from garden for replanting. Use resistant varieties (such as Lancer, Provider, Blue Bush 274, Golden Butterwax, Royal Burgundy, Tendercrop, and Improved Tendergreen). Pesticide control of insect vectors (aphids and leafhoppers) is not effective in preventing virus transmission, which occurs within seconds of the insect probing the leaf to initiate feeding. The virus occurs in many weeds and crops like alfalfa, so aphids can continually bring in the disease from outside the garden.
Leaf mosaic and distortion caused by bean common mosaic virus.
	Botrytis gray mold	Follow disease sanitation practices* (see note). If needed, apply Bacillus subtilis or chlorothalonil, following label directions.
	Rust	Follow disease sanitation practices* (see note). If needed, apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, myclobutanil, neem oil, or sulfur.
	Aphids	Wash off with a strong stream of water. Among the products available for aphid control are pesticides containing: horticultural oil, insecticidal soap (potassium salts of fatty acids), insecticidal soap with pyrethrins, kaolin clay (for suppression), malathion, Mite-X (plant extracts), neem oil, permethrin, or pyrethrins with canola oil.
	Leafhoppers	If leafhoppers are present, apply carbaryl, insecticidal soap (potassium salts of fatty acids), insecticidal soap with pyrethrins, kaolin clay (for suppression), malathion, neem oil, permethrin, or pyrethrins with canola oil.
	Mexican bean beetle and Japanese beetle	Handpick and remove beetles. If needed, apply carbaryl, horticultural oil (for Japanese beetles), insecticidal soap (potassium salts of fatty acids), kaolin clay (suppression only), malathion, neem oil, permethrin (for Mexican bean beetles), or pyrethrins with canola oil.
	Seedcorn maggot	Purchase insecticide-treated seed. Wear gloves when planting.
	Spider mites (two-spotted)	Wash off with a strong stream of water. If needed, use insecticidal soap (potassium salts of fatty acids), kaolin clay (for suppression), malathion, or neem oil.
Beet	Cercospora leaf spot	Follow disease sanitation practices* (see note). If needed, apply Bacillus subtilis or copper soap (copper octanoate).
	Leafminers	Remove mined leaves when first seen, and destroy. Beets are typically not sprayed for leafminers except if leaves intended for consumption are infested. Use horticultural oil, or neem oil. Some products require a longer number of days between application and harvest; check labels.
Cabbage, cauliflower, broccoli, Brussels sprouts, and other cole crops	Clubroot (Plasmodiophora brassicae)	No pesticides are currently registered for home garden use. Rogue plants: remove and discard or destroy entire infested plant along with immediately surrounding soil and soil clinging to roots. If soil is infested, add lime to raise soil pH to 7.2. Locate new plants in a part of the garden different from previous year’s location. If that is not possible, remove infested soil and replace with fresh soil. Purchase healthy transplants or start seed in sterile potting mix or fresh ground.
	Cabbage aphids	Wash off with a strong stream of water. If needed, use horticultural oil, insecticidal soap (potassium salts of fatty acids), insecticidal soap with pyrethrins, malathion, Mite-X (plant extracts), neem oil, permethrin, or pyrethrins with canola oil. Spray when infestations are excessive and weekly if needed.
	Cabbage root maggot	Entomophagous nematodes may be used. Apply as directed on label.
	Cabbageworms	Handpick and remove caterpillars. Use Bt (Bacillus thuringiensis ssp. kurstaki), carbaryl, insecticidal soap (potassium salts of fatty acids), malathion, neem oil, permethrin, or spinosad.
	Flea beetles	If needed, use carbaryl, insecticidal soap (potassium salts of fatty acids), kaolin clay (flea beetles), neem oil, or pyrethrins with canola oil.
Carrot and parsnip	Alternaria (late blight)	Apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, or copper soap (copper octanoate).
Note: Not all pesticides are labeled for use on parsnip. Check label prior to use.	Cercospora (early blight)	Apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, or copper soap (copper octanoate).
	Carrot rust fly	No pesticides are currently registered for home garden control. To avoid second brood injury, harvest all carrots by September 1 in upstate New York or by August 20 farther south.
	Carrot weevil	Use entomophagous nematodes. Apply as directed on label.
	Leafhoppers	If needed, use carbaryl, insecticidal soap (potassium salts of fatty acids), kaolin clay (suppression only), neem oil, permethrin, or pyrethrins plus canola oil.
Corn	Helminthosporium leaf blight	Apply Bacillus subtilis or chlorothalonil.
	Rust	Choose resistant or tolerant varieties. Sweet Sue and Silver Queen are very susceptible. For se bicolor types try: Temptation, Sensor, or Lancelot. Follow disease sanitation practices* (see note). Before tassel emergence, apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, or neem oil. Repeat if disease is severe and weather is warm during the day and cool at night. Stop applications before the minimum number of days-to-harvest given on the product label.

	Smut	Pick and remove galls before they break open. Plant resistant or tolerant varieties such as Sweet Rhythm, Wizard, Sweet Symphony, Lancelot or Silverado.
	European corn borer, Corn earworm	Spray or dust foliage and silks with carbaryl or permethrin. Apply when tassels begin to emerge and thereafter if needed. To control corn borer, release Trichogramma ostriniae wasps. For corn earworm, apply Bt (Bacillus thuringiensis ssp. kurstaki).

	Seedcorn maggot	Use insecticide-treated seed. Wear gloves when planting.
Cucumber	Cucumber mosaic virus	Pesticide control of insect vectors (aphids) is not effective in preventing the spread of virus, which occurs within seconds of the insect probing the leaf to initiate feeding. Because the virus occurs in many weeds, aphids will continually bring in the disease from outside of the garden.
	Downy mildew	Apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, copper soap (copper octanoate), or neem oil.
	Gummy stem blight (Black rot)	These are two stages of the same disease. Apply azoxystrobin (not near apples), chlorothalonil, or copper sulfate.
	Powdery mildew	Select PMR (powdery mildew resistant) varieties such as Marketmore 76 and 78, Dasher II, Turbo, or Meteor . Follow disease sanitation practices* (see note). If needed, apply azoxystrobin (not near apples), Bacillus subtilis, chitosan, chlorothalonil, copper soap (copper octanoate), kaolin clay (for suppression), neem oil, or sulfur. Rotate among fungicides to delay fungicide resistance.
	Aphids	Wash off with a strong stream of water. If needed, use horticultural oil, insecticidal soap (potassium salts of fatty acids), insecticidal soap with pyrethrins, kaolin clay (for suppression), malathion, Mite-X (plant extracts), neem oil, permethrin, or pyrethrins with canola oil. Spray if needed, when vines are dry.
	Cucumber beetles (striped or spotted) Striped cucumber beetle.	Handpick and remove beetles. Control of beetles is important to prevent bacterial wilt in cucumbers. If needed, use carbaryl, insecticidal soap (potassium salts of fatty acids), kaolin clay (suppression only), neem oil, permethrin, or pyrethrins (with other ingredients). Apply when beetles are excessive, and weekly if needed (check product label).
	Squash vine borer	Destroy crop residues after harvest to reduce the overwintering stage. Inject entomophagous nematodes (Heterorhabditis bacteriophora) or apply kaolin clay (suppression only) or permethrin.
Eggplant	Aphids	Wash off with a strong stream of water. If needed, use insecticidal soap (potassium salts of fatty acids), insecticidal soap with pyrethrins, kaolin clay (for suppression), malathion, Mite-X (plant extracts), or neem oil..
	Colorado potato beetle	Handpick and remove beetles. If needed, use carbaryl, insecticidal soap (potassium salts of fatty acids), kaolin clay (suppression only), neem oil, permethrin, pyrethrins with other ingredients that’s labeled for Colorado potato beetle on eggplant, or spinosad.
	Flea beetles	Use carbaryl, insecticidal soap (potassium salts of fatty acids), kaolin clay (suppression only), neem oil, or pyrethrins with other ingredients that’s labeled for Colorado potato beetle on eggplant. Apply after transplanting and until plants are well established.
Muskmelon, cantaloupe	Downy mildew	If severe, apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, copper soap (copper octanoate), copper sulfate, or neem oil.
	Fungal leaf spots	Follow disease sanitation practices* (see note). If severe, apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, copper soap (copper octanoate), copper sulfate, or neem oil.
	Gummy stem blight (Black rot)	Apply azoxystrobin (not near apples), chlorothalonil, or copper sulfate.
	Powdery mildew	Use a mildew resistant (PMR) variety, such as Athena. Follow disease sanitation practices* (see note). If needed, apply azoxystrobin (not near apples), Bacillus subtilis, chitosan, chlorothalonil, copper soap (copper octanoate), copper sulfate, kaolin clay (for suppression), neem oil, or sulfur. Rotate among fungicides to delay fungicide resistance.
	Cucumber beetles (striped or spotted)	Handpick and remove beetles. When beetles are excessive or repeatedly if needed (check label directions), apply horticultural oil, insecticidal soap (potassium salts of fatty acids), kaolin clay (suppression only), malathion, permethrin, or pyrethrins with other ingredients labeled for cucumber beetle control on melons. Control of beetles is important to prevent bacterial wilt in cucumbers, but less important with other vine crops.
	Squash vine borer	Destroy crop residues after harvest to reduce the overwintering stage. Inject entomophagous nematodes (Heterorhabditis bacteriophora) or apply kaolin clay (suppression only) or permethrin.
Onion	Botrytis leaf blight	If disease is severe, apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, copper soap (copper octanoate) or neem oil. Do not use chlorothalonil on Sweet Spanish onion.
	Downy mildew	If severe, apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, copper soap (copper octanoate), copper sulfate, or neem oil.
	Purple blotch (Alternaria porri)	Follow disease sanitation practices* (see note). If disease is severe, apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, or copper sulfate.
	Onion maggot	Avoid high organic matter soils. Use malathion if needed.
	Thrips	Use capsaicin, Mite-X (plant extracts), insecticidal soap (potassium salts of fatty acids), kaolin clay (suppression only), malathion, or neem oil.
Pea	Seed decay and seedling root rots	Avoid planting where peas or beans were growing previously. Improve soil drainage. Wait for soil to warm in spring before planting. Purchase fungicide-treated seed; wear gloves when handling.
	Aphids	Wash off with a strong stream of water. If needed, use insecticidal soap (potassium salts of fatty acids), kaolin clay (suppression only), malathion, Mite-X (plant extracts), neem oil, or pyrethrins with other ingredients and labeled for aphids on peas.
	Seedcorn maggot	Purchase insecticide-treated seed. Wear gloves when planting.
Pepper	Cucumber mosaic virus	Rogue plants: remove and destroy diseased plants, along with immediately surrounding soil. Cucumber mosaic virus causes ringspots and oak leaf patterns on peppers. Pesticide control of insect vectors (aphids) is not effective in preventing the spread of virus, which occurs within seconds of the insect probing the leaf to initiate feeding. Because the virus occurs in many weeds, aphids will continually bring in the disease from outside of the garden.
	Gray mold	Follow disease sanitation practices* (see note). Use Bacillus subtilis or copper soap (copper octanoate).
	Aphids	Wash off with a strong stream of water. If needed, use horticultural oil, insecticidal soap (potassium salts of fatty acids), insecticidal soap with pyrethrins, kaolin clay (for suppression), malathion, Mite-X (plant extracts), neem oil, permethrin, or pyrethrins with canola oil.
	Borers	Use carbaryl or permethrin, if needed.
Potato	Early blight and Late blight	Use disease-free seed potatoes. Follow disease sanitation practices* (see note). Confirm diagnosis before treating. Following label directions for timing, apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, copper soap (copper octanoate), or copper sulfate. The fungus that causes late blight has become a major threat to home gardens and commercial growers because of the migration of new strains (genotypes) into the United States. Veriﬁcation of a late blight diagnosis and implementation of prompt control measures are highly recommended. The newly arrived strains of the fungus are more aggressive than previous strains. Protectant fungicides (chlorothalonil or copper products) should be used at first appearance of disease.
	Scab, Silver Scurf, Rhizoctonia Potato scab.	No pesticides are currently registered for home garden use. Use certified disease-free seed potatoes.
	Viral diseases	Use certified disease-free seed potatoes. Rogue out and destroy diseased plants.
	Aphids	Wash off with a strong stream of water. If needed, use insecticidal soap (potassium salts of fatty acids), insecticidal soap with pyrethrins, malathion, Mite-X (plant extracts), neem oil, permethrin, or pyrethrins with canola oil.
	Colorado potato beetle	Handpick and remove beetles. If needed, use carbaryl, insecticidal soap (potassium salts of fatty acids), kaolin clay (suppression only), neem oil, permethrin, pyrethrins with other ingredients labeled for Colorado potato beetle on potato, or spinosad. Spray or dust weekly if needed. Beetles may be resistant to synthetic insecticides.
	Flea beetles	Use carbaryl, insecticidal soap (potassium salts of fatty acids), kaolin clay (suppression only), neem oil, permethrin, or pyrethrins with other ingredients labeled for flea beetle control on potato.
	Leafhoppers	Use carbaryl, insecticidal soap (potassium salts of fatty acids), kaolin clay (suppression only), malathion, neem oil, permethrin, or pyrethrins with other ingredients labeled for leafhopper control on potato..
Pumpkin	Downy mildew	If needed, apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, copper soap (copper octanoate), copper sulfate, or neem oil.
	Gummy stem blight (Black rot)	Apply azoxystrobin (not near apples), chlorothalonil, or copper sulfate.
	Powdery mildew	Select powdery mildew tolerant varieties, such as: Merlin, Mystic Plus, Magic Lantern, or Aladdin. Follow disease sanitation practices* (see note). If needed, apply azoxystrobin (not near apples), Bacillus subtilis, chitosan, chlorothalonil, copper soap (copper octanoate), copper sulfate, kaolin clay (for suppression), or neem oil. Rotate among fungicides to delay fungicide resistance.
	Aphids	Wash off with a strong stream of water. If needed, use horticultural oil, insecticidal soap (potassium salts of fatty acids), insecticidal soap with pyrethrins, kaolin clay (for suppression), malathion, Mite-X (plant extracts), neem oil, permethrin, pyrethrins with canola oil,.
	Cucumber beetles (striped or spotted)	Handpick and remove beetles. When beetles are excessive or repeatedly if needed (check label directions first), apply horticultural oil, insecticidal soap (potassium salts of fatty acids), kaolin clay, permethrin, or pyrethrins with other ingredients and labeled for use against cucumber beetles on pumpkins. Control of beetles is important to prevent bacterial wilt in cucumbers but less important with other vine crops.
	Mites	Wash off with a strong stream of water. If needed, use insecticidal soap (potassium salts of fatty acids), malathion, Mite-X (plant extracts), or neem oil.
	Squash bug	Handpick and remove adult and nymph squash bugs. Use carbaryl, insecticidal soap (potassium salts of fatty acids), kaolin clay, neem oil, permethrin, or pyrethrins with canola oil. Spray on foliage if needed.
	Squash vine borer	Destroy crop residues after harvest to reduce the overwintering stage. Inject entomophagous nematodes (Heterorhabditis bacteriophora) or apply kaolin clay . Malathion can be used if there is a history of problems: apply first spray about June 20 to stems and vines at base of plant; then apply three times thereafter at seven-day intervals.
Radish and turnip	Maggots	No pesticides are currently registered for home garden use. If radishes are planted weekly, some plants will avoid being damaged.
Rhubarb	Fungal leaf spot (Alternaria, Cercospora, Septoria)	Follow disease sanitation practices* (see note). If needed, apply azoxystrobin (not near apples) early in spring when peonies emerge. Or use Bacillus subtilis.
Spinach	Leafminer	Remove mined leaves when first seen and destroy. If needed when mines appear and, if necessary, at seven-day intervals thereafter (check label directions), apply neem oil, or spinosad. Note: a multipurpose product with insecticidal soap and sulfur should not be used as noted on the label; it damages spinach.
Squash	Downy mildew	If needed, apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, copper soap (copper octanoate), copper sulfate, or neem oil.
	Gummy stem blight (Black rot)	Apply azoxystrobin (not near apples), chlorothalonil, or copper sulfate.
	Powdery mildew	Select resistant (PMR) squash varieties. Follow disease sanitation practices* (see note). If needed, apply azoxystrobin (not near apples), Bacillus subtilis, chitosan, chlorothalonil, copper soap (copper octanoate), copper sulfate, kaolin clay (for suppression), or neem oil. Rotate among fungicides to delay fungicide resistance. Chlorothalonil will suppress mildew but will control other foliar diseases.
	Squash bug	Handpick and remove adult and nymph squash bugs. Use carbaryl, insecticidal soap (potassium salts of fatty acids), kaolin clay, neem oil, permethrin, or pyrethrins with canola oil. Spray on foliage if needed.
	Squash vine borer	Destroy crop residues after harvest to reduce the overwintering stage. Inject entomophagous nematodes (Heterorhabditis bacteriophora), or apply kaolin clay.
Tomato	Anthracnose	Follow disease sanitation practices* (see note). If needed, apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, copper soap (copper octanoate), copper sulfate, or neem oil.
	Early blight, Septoria leaf spot	Try an Early Blight tolerant variety such as Mt. Supreme. Follow disease sanitation practices* (see note). If needed, use azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, copper soap (copper octanoate), or copper sulfate. Septoria occurs early in the season, preferring cool, wet weather. Use clean transplants, and remove lower infected leaves. Dark spots caused by early blight.

	Late blight	Follow disease sanitation practices* (see note). If diagnosis is confirmed, use azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, copper soap (copper octanoate), or copper sulfate. The fungus that causes late blight has become a major threat to home gardens and commercial growers because of the migration of new strains (genotypes) into the United States. Verification of a late blight diagnosis and implementation of prompt control measures are highly recommended. The newly arrived strains are more aggressive than previous strains. Protectant fungicides (chlorothalonil or copper products) should be used at first appearance of disease.
	Aphids	Wash off with a strong stream of water. If needed, use horticultural oil, insecticidal soap (potassium salts of fatty acids), insecticidal soap with pyrethrins, kaolin clay (for suppression), malathion, Mite-X (plant extracts), neem oil, or pyrethrins with canola oil.
	Colorado potato beetle	Handpick and remove beetles. If needed, use carbaryl, insecticidal soap (potassium salts of fatty acids), kaolin clay (suppression only), neem oil, permethrin, pyrethrins with other ingredients and labeled for Colorado potato beetle on tomato, or spinosad.
	Cutworms	Use permethrin or spinosad. Slug bait of iron phosphate plus spinosad may be used for cutworm control.
	Flea beetles	Use carbaryl, insecticidal soap (potassium salts of fatty acids), kaolin clay (suppression only), neem oil, or pyrethrins with other ingredients that are labeled for flea beetle control on tomato.
	Hornworm	Handpick and remove caterpillars. If too numerous, use Bt (Bacillus thuringiensis ssp. kurstaki) while caterpillars are small. Or when needed, apply carbaryl, kaolin clay (suppression only), permethrin, pyrethrins with other ingredients and labeled for hornworm control on tomato, or spinosad.
	Stink bugs	Handpick and remove. Use carbaryl or neem oil if needed.
	Whiteflies	Apply horticultural oil, insecticidal soap (potassium salts of fatty acids), malathion, neem oil, or pyrethrins with other ingredients and are labeled for whitefly control on tomato.
Vegetables	Slugs and snails Slug	Handpick and remove. Iron phosphate baits may be spread on the ground. Metaldehyde or carbaryl plus metaldehyde, may be used where pets or wildlife have no access. Caution: baits may resemble pet food. Be sure to place baits where children, pets, or wildlife cannot get into them.

Pest Management Guidelines A Cornell Cooperative Extension Publication	New York Pest Management Guidelines
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Muskmelon, cantaloupe