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Outline

Integrated Pest Management And The Vegetable Garden

What is IPM ? Integrated Pest Management (IPM) is a sustainable approach to managing pests  by combining biological, cultural, physical and chemical tools in a way that minimizes economic, health and environmental risks.

Why IPM in the Veggie Garden . . . Every home garden attracts insects. Every gardener encounters bugs on their broccoli and beetles on their beans every summer. Every problem may not require hauling out the insecticide.

To Get That IPM Attitude Become A Sleuth!

So did the bugs do it? Enough sun?  Gardens need at least six hours of sunlight. Over or under watering?  Should be about 1 inch per week. Bad weather?  Hail, wind , extreme heat, cold, or humidity. Critter problems? Rabbits, voles, mice, dogs, cats

More environment clues . . . Was the plant stunted during development, planted too early or late, over/under watered? Is there enough air circulation? Check with a magnifying glass to see if damage is insect or disease. Check to ensure roots are healthy.

So you’ve found bugs, now what? 10% of the bugs in your garden are bad. 80% of the bugs are either harmless or helpful. The goal is to slow down the bad bugs and encourage the good ones.

Don’t murder the good guys! Green Lace Wings Lady Beetles Spiders Damsel Bugs Hoover Flies

Friend– Green Lace Wing Green lacewings are predators found in most environments. It’s a voracious feeder and can consume up to 200 aphids or other prey per week. It also eats mites and a wide variety of soft-bodied insects, including insect eggs, thrips, mealy bugs, immature whiteflies, and small caterpillars. Lacewings will also consume each other if no other prey is available.

Friend – Lady Beetles The importation of the predacious vedalia beetle, a scale-feeding lady beetle species, saved the citrus industry in California from the cottony cushion scale. The mealybug destroyer, another lady beetle species, was introduced into California in 1928 and is now commercially available for mealybug suppression. In the Midwest several very common lady beetle species are aphid predators, including the twelvespotted lady beetle, the convergent lady beetle, the sevenspotted lady beetle and the twospotted lady beetle.

Friend– Lady Beetles These species of predatory insects are common in most agricultural and garden habitats in the Midwest. Their beneficial predatory behaviors should be recognized and the presence of lady beetles indicates that natural biological control is occurring. Their activity can be encouraged through the reduced use of insecticides or the use of selective insecticides. Also, the planting of a variety of crops or creating habitats for beneficial insects may provide lady beetle species with several types of prey and possible nectar and pollen sources.

More – Lady Beetles The larval stages of these species are not as easily recognized as the adults, but are also predators of pest insects. The size and coloration of the larval stages vary among the species, but generally the larvae are soft bodied and shaped like a miniature alligator. Newly hatched larvae are gray or black and less than 1/8 inch long. Later stage larvae can be gray, black, or blue with bright yellow or orange markings on the body.

More – Lady Beetles Adults of the twelvespotted lady beetle are about 1/4 inch long and have pink to light red colored wing covers with six black spots on each wing. Adults of the convergent lady beetle, 1/4 inch long, have orange wing covers, with six small black spots on each. Behind the head is two converging white lines, hence the name. Yellow eggs are in clusters of 10-20. The sevenspotted lady beetle has red wing covers with seven black spots and lays 15 – 70 yellow eggs on plants that are infested with their aphid prey.

Friend – Spiders All spiders are general predators of insects and provide natural control. Some construct webs. Others hunt down their prey. Insects from egg to adult stage are prey. The hunt method determines the type and stage of insect eaten. Spiders are generalist predators and do not discriminate. They may eat the good guys, however, if there is an abundance of any type insect, spiders can help to balance and stability to the insect population. Spiders tend to have a single generation per year, and do not rapidly increase their numbers. Many broad spectrum insecticides directly kill spider populations as well as beneficial insects.. Therefore, insecticides should be used only when needed and the most selective materials possible should be used.

Friend – Damsel Bugs Damsel bugs are slender, tan-colored bugs that resemble small, assassin bugs. They are a small family of generalist predators commonly found in many gardens. Damsel bugs feed on many types of insects - aphids, moth eggs, and small caterpillars, including corn earworm, European corn borer, imported cabbageworm and some armyworms.  Other prey may include leafhoppers (including beet and potato leafhoppers), small sawfly larvae, mites, tarnished plant bug nymphs, and asparagus beetle and Colorado potato beetle eggs and nymphs. Although they can survive for up to two weeks without food, if no other prey is available they will turn to cannibalism.

Friend – Hover Flies Hover flies (or flower flies,) are common and important natural enemies of aphids and other small, slow-moving insects. The adults resemble bees or wasps, and are often seen visiting flowers, hovering over the flowers and darting around. There are many different species that range in size from less than 1/4 inch long to more than 3/4 inch long. Many have the typical black and yellow stripes on the abdomen that give them a bee-like appearance, but others are hairy with a long, thin abdomen. They are attracted to weedy borders or mixed garden plantings that are also infested with aphids. The adults need flowers as nectar and pollen sources, especially Queen Anne's lace, wild mustard, sweet alyssum, coriander, dill, and other small-flowered herbs.

Friend – Assassin Bugs Most assassin bugs are medium-sized to large predators of crop pests, but the family does contain a few blood- sucking species. Even the beneficial insect predators can inflict a painful bite if handled carelessly, resulting in an inflammation that can persist for a few days. Adult assassin bugs are usually 1/2 to 3/4" long. Many species are brownish or blackish, but some species are brightly colored. The elongated head is narrow with a distinct "neck" behind the often reddish eyes. The long, curved mouth parts form a beak which is carried beneath the body.with the tip fitting in a groove on the underside of the body. The female lays eggs in tight, upright clusters on leaves or in the soil. Nymphs resemble miniature, wingless adults. Most assassin bugs are generalist predators.They sit in wait of prey and are most likely to attack small flying insects, however they can subdue and kill medium-sized caterpillars and similar insects. In the garden they attack aphids, leafhoppers and asparagus beetle eggs and larvae. They may feed on beneficial species as well as pests. To preserve them, judicious pesticide use is beneficial.

Friend –Pirate Bugs Minute pirate bugs are common insect predators. Both immature stages and adults feed on a variety of small prey, including spider mites, insect eggs, aphids, thrips, and small caterpillars. They feed by sucking juices from their prey through a sharp needle-like beak. Adults are very small (1/8" long). Females lay tiny eggs within plant tissues where they are not easily seen. These hatch into nymphs, the immature feeding stage. Nymphs are small, wingless insects, yellow-orange to brown in color, teardrop-shaped and fast moving. Several generations may occur during a growing season. Pirate Bugs may even bite humans, but the bite is only temporarily irritating. They feed on pollen and plant juices when prey are not available and therefore are very susceptible to insecticides.

Ground Beetles Ground beetles are common important predators that vary in size from a less than 1/4" to over 1-1/2" long. They are usually dark brown or black, shiny, and somewhat flattened, with slender legs for running. A few are an  iridescent blue or green. They rarely fly. They are commonly found under leaves or debris, in cracks in the soil, or running along the ground. Some species emit a strong smelling irritant when handled. Many are nocturnal and some are attracted to lights at night. The adults are fierce predators that chew up their prey with their large, sharp mouthparts. Caterpillars, grubs and adults of other beetles, fly maggots and pupae, earthworms, and other small soil dwellers are common prey. They can consume their body weight in food daily. Eggs are deposited either on objects above ground or in cavities made in the soil.

Rove Beetles Adult rove beetles are generally less than 3/4 inch long. They are easily recognized by their slender, usually black or brown body, shortened front wings (elytra) that may look like pads on the abdomen, and behavior of curling the tip of the abdomen upwards when disturbed or running. Adults are usually strong fliers. The mobile larvae of non-parasitic rove beetles may be distinctly segmented Predaceous rove beetles, depending on the species, may consume root maggot eggs and larvae, mites, small soil insects, insect eggs, or small insects on foliage. Some feed on the eggs and maggots of filth flies. Several occur in agricultural soils where they probably feed on a variety of types of prey. A few species can be found in vegetation where they feed on many types of small insects and mites.

Friends – How to save them and still thwart the bad guys Garden Housekeeping Change Your Attitude Rotate Crops Intercrop Change/stagger  Planting Times Physical Removal Traps and Barriers Feed the good guys Careful Pesticide Use

Option - Housekeeping Do a spring and fall debris clean up . Destroy or burn any plant material from badly infested plants. This will destroy eggs. When removing infested plants, bag immediately so bugs do not “shake out” on healthy plants. Keep to minimum empty pots, boards, and other things gardeners tend to collect. Prevent hiding and breeding spots. Do leave some spider webs. Use common sense. Try for balance, not picture perfect.

Option – Change Your Attitude A bug free garden is not a healthy garden. Nature is a balancing act. Let it help you. Perfect looking is not perfect tasting. Not everything grows perfectly every year. Use insecticides as a last resort and only when infestations are out of control.

Option – Rotate Crops Make the bad guys hunt for their food. They may give up. Try for a three year rotation. Same plant, same spot, once in three years. Even rotation is small beds helps. This also helps prevent disease and stabilizes soil nutrients.

Option – Intercrop Bad bugs are usually host specific. They eat only one kind of plant. To confuse them, mix your plants up, either by row, block  or different sections of the garden. An added bonus for small gardens is that you can utilize more space, i.e root crops next to cole crops. Intersperse vegetables with pest retardant flowers like marigolds or pyrethrum daisies. If you discover a plant they particularly like in your garden, plant one or two early to attract the bad bugs and plant the real crop a bit later somewhere else.

Option – Change Or Stagger Planting Times Most pests have a peak destruction period. If they attack the mature plant, plant earlier so you can harvest before they do their damage. If they attack the young plants, delay planting to avoid them. 2002 bean beetles are an example of this. They ate the early crops but not the later ones.

Option – Physical Removal Remove aphids with a blast of the hose or use two brushes to wipe them off. They are not likely to climb back up the plant. Watch for egg cases on plant leaves and remove. Hand pick adult bugs. If using fingers makes you squeamish, knock them into a container of water and oil using a stick. Use a Dust Buster or portable vac to vacuum up flying insects, especially white flies.

Option – Traps And Barriers Copper, ashes or egg shells are a barrier to snails and slugs. Use floating row covers to keep insects out. Remove for pollination. Sticky traps catch white flies (yellow surface) and apple maggot flies (use red spheres). Coat with sticky coating such as Tanglefoot. Plastic or paper collars stop cutworms. Trap earwigs with a sunken tuna can filled with fish oil or oil-soaked bread crumbs. Plain water or beer also attracts some bugs. Carrot and potato “bait” traps wireworms. Stick pieces of either on a stake into the soil. Chunks of fresh squash attract adult cucumber beetles. Boards, rolled or flat newspapers, upside-down melon rinds are often hiding places to trap bag bugs. Don’t forget to remove and kill trapped bugs.

Option – Feed The Good Guys Balance is the trick. Leave enough of the bad guys around  to feed the good guys or they will eat each other or move away. A healthy balance allows your  plants to grow with relatively little damage and keeps enough insects around for good pollination.

Insecticidal Soap Recipe Combine 1 tablespoon of a dishwashing liquid with 1 cup of vegetable oil to make a concentrate. When ready to apply, add 1 tablespoon concentrate to 1 cup of water and spray it on the plants. It's important to experiment with the solution first. You may decide to dilute the concentration because you can easily burn the plants. Note: On white flies the oil will suffocate the flies and their eggs. The soap will help to break down the waxy covering on their bodies making them more susceptible to disease and their natural predators.

Option – Use Nontoxic Sprays Insecticidal soap smoothers bad bugs. Make your own by putting a bit of dish detergent plus a few drops of cooking oil in water. (If you add baking soda it will also change the pH and inhibit fungus and mildew.) Warning: This will make plants more susceptible to sunburn. Use on a cloudy day or late in day. It can be hosed off later. Watch for new nontoxic commercial sprays.

Option – Careful Pesticide Use Use pesticides only when the bad bugs are out of control. Always follow the directions. Stronger applications are NOT good. Spraying in the evening will avoid harming many good bugs, especially bees. Remember, good guys feed on pollen and plant juices when prey are not available. Foliar or systemic applications can greatly reduce Good Guy numbers. Even soil applied systemic insecticides may reduce their numbers because of their habit of sucking plant juices. Diversified cropping and use of microbial insecticides, e.g., products containing Bacillus thuringiensis are all practical recommendations to maximize the natural biological control.

And Now For Some Bad Guys. . .

Enemy – Aphids Pear shaped adults colonize quickly, especially on new growth. They suck juice from plants and at times are colonized by ants which harvest the aphid honeydew. Aphids over winter on woody stems hatching in spring. Females give birth continuously to live nymphs without mating. Males hatch in fall. Control: physical removal, predator bugs, birds -  especially small warblers. Suffocate them with insecticidal or light oil spray.

Enemy – Cabbage Loopers The moths are nocturnal fliers that rest on the underside of cabbage leaves days. White, pinhead size eggs are laid singly near the outer edge of loser leaves of uninfested plants. Eggs hatch in 3 to 6 days and larvae immediately begin feeding. They slow down in cooler fall weather. Control: Watch for and destroy eggs when you see moths flying. Hand pick loopers. Bt helps and is easy on beneficial insects. This insect cannot over winter in the Midwest. Adult Looper moths annually migrate here.

Corn Earworm - Snap Beans Has a wide host range including corn, tomatoes, snap beans. Moths are green-eyed, buff-colored, with a wingspan of about 1½ inches. Fully grown larvae are about 2 inches long. Migrate here around mid-June and again in August. Beans are vulnerable from bud stage to harvest. Larvae feed on the outside of and burrow into the pod. Hand pick. Treat with an effective CEW insecticide (Sevin) if beans are at a vulnerable stage. Beans should be treated on a 5-7 day schedule

Enemy - Flea Beetles Occasional pests on cole crops, potatoes, corn and spinach with enlarged hind legs for jumping. Feeding causes a "shothole" appearance to the plants. Heavy attack results in wilted or stunted plants. Transplants withstand better than seed starts. Adult eat stems and foliage. Control: Early season trap crop of cole or radish. Adults feed on earliest and tallest plants. Use insecticide to kill pests on trap crops or collect and destroy plants. (Have another trap to replace.)

Enemy - Four-Lined Plant Bug Easily identified with wide range of hosts –  fruits, vegetables, flowers, herbs, and cucurbits. Piercing-sucking insect. Damage consists of spots similar to fungal  disease. Can be misidentified as such. Usually not severe enough to cause plant death. Eggs will over winter in host debris. Feeding produces white, dark, or translucent spots 1/16 to 1/8 in. on the plant's leaves. Entire leaves can turn brown. Begin to check plants in mid-spring around May and June. Control: Insecticidal soaps and dormant or summer horticultural oils are useful. Handpicking highly visible eggs is effective. For severe damage, spray in May and June with . malathion

Enemy – Leaf Hoppers Migrates here to feed on over 100 plants – eggplants, strawberries, potatoes, soybeans, and especially snap beans. Most active late June to early August. Piercing-sucking insects, they rob plant of food. Also inject a damaging saliva the stunts growth. First signs are pale leaf veins and curling leaves. There may be a v-shaped brown area at the leaf tip that is called hopperburn. Note: Curled, chlorotic foliage is also sometimes a symptom of a nutrient deficiency so identify carefully. Pathogens and parasites predators are not too effective. Chemical insecticides are usually the best way to control. Start checking mid-May.

Colorado Potato Beetle In MN, the beetle over winters in areas surrounding potato fields. In spring they lay clusters of 10 – 30 yellow eggs on the underside of the leaf. Has few natural enemies. Larvae move throughout the plant and consume leaves. Is one of the few “super” pests in agriculture. Has developed resistance to most insecticides. Hand pick.

Enemy – Squash Bug Feed on vine crops causing damage and wilt by sucking nutrients from leaves. Yellow specks develop on foliage, then turn brown. Can look similar to bacterial wilt, a disease spread by striped cucumber beetles which kills plants. Plants recover from Squash bug damage. Monitor seedling, transplant and flowering stage. Hand pick and destroy squash bugs and eggs. Set out boards or shingles next to the plants. Bugs will aggregate at night and can then be destroyed each morning. Using resistant varieties. Sabadilla may provide some control and is organic certified.

Enemy – Squash Vine Borer Occasional pest of vine crops in MN. Moths are fast, noisy daytime flyers sometimes mistaken for wasps. Adults emerge from cocoons in soil mid-June to July. 1-inch larvae immediately bore into stem causing wilt. Entrance hole has  yellowish frass.  They exit after a month. Control: When hole and frass appear, split stem and remove worm. (Bury cleaned  stem and it may re-root.) Plant resistant varieties. Destroy infected crops. In June-July use floating row covers with firmly anchored edges.

Striped Cucumber Beetle Attacks cucumbers, melons causing direct feeding damage on foliage and fruit. Also spreads bacterial wilt pathogen. Become active the first week of June. Adults feed on alternate hosts such as hawthorn, dandelions while waiting for cucumbers to grow. Females lay eggs at plabt  base. Larvae feed on the roots and underground portions of stems.Adults feed on foliage, flowers and fruit. They hide in the soil around the plant to escape predators or the heat of the day and feed on stem base. Bacterial wilt problems happen about 1 out of 5 years in MN. Control with trap crops Start a few plants two weeks early. Sevin provides an effective knockdown of major infestation.

Enemy – White Flies Gnat-like pests that weaken plants and cut down on their yield. Birds and predator bugs feed on them. For control, try to reduce numbers. Total irradication is difficult. Blast with hose. Vacuum. Shake plant while vacuuming to get them into the air. Use insecticidal soap, home made or commercial. Use yellow or white sticky pads.

Enemy – Herbicide Drift Leaves of plants suddenly begin to wilt and curl. You may think you have an insect pest causing the leaves to roll or curl. Check if there has been a recent lawn herbicide sprayed near your garden. Washing down plants generously with hose may help. If plant yellows, then curls, check for leaf hoppers

A Happy Ending For Your Vegetables

A Happy, Healthy Ending For You!