PESTS AND DISEASESIn the Vegetable Garden

DISEASES IN THE VEGETABLE GARDEN

BACTERIAL WILT

SymptomsPlant will wilt and die

quicklyEarly on center of stem

appears water-soakedLater it stem appears

brown and may hollowAffects tomatoes,

potatoes, eggplants & peppers & cucumbers

Favorable ConditionsWarm, wet weather of late

spring & early fallManagement Practices

Rotate CropsRemove and destroy plantsReplace soil surrounding plant

BLOSSOM END ROT Symptoms

Brown to black, leathery rot near the blossom end of the fruit

Lesion gets bigger as the disease worsens

Management Practices

Make sure plants are fertilized and watered properly

Mulch

Caused by lack of sufficient calciumMost severe following extremes in soil moisture (either too dry or too wet)Applying too much fertilizer at one time can result in blossom end rot

EARLY BLIGHT Symptoms

Spots are dark brown to black. Concentric rings develop in the spot forming a bulls eye. Leaf eventually turns yellow.

Starts on the lower leaves Overwinters on old tomato vines Occurs during cool, rainy weather Also affects peppers

Management Practices Rotate crops Plant disease free seeds Use resistant cultivars At season end clean up garden

thoroughly Avoid getting the leaves wet Apply fungicides as

appropriate(before the disease first appears)

LATE BLIGHT Symptoms

Lesions that are large, irregular and gray with white mold

Fruit will be firm and rotted Management Practices

Use disease free plants and seeds & resistant varieties

At the end of the season be sure to clean up the garden thoroughly

Apply fungicides containing copper as appropriate (before disease appears)

Thrives in cool, moist conditions, or high humiditylevels.

OTHER TOMATO PROBLEMS Leaf Roll

Happens when there is a period of heavy rainfall that keeps the soil constantly moist.

Keep soil well drained & well aerated

Edges of leaves curl up to form cups; then the edges overlap & the leaves become firm & leathery to the touch.

Fruit with cracks Cracks radiate from stems

and around the shoulders Caused by hot, rainy

weather To avoid do not overwater

Blossom Drop Prevalent in cool rainy

weather or where soil moisture is low and winds are hot & dry.

Large fruited tomatoes are particularly vulnerable

ANTHRACNOSE Symptoms

Sunken, reddish to black lesions on the bean pods, leaves & stems

Also affects peppers, cucumbers & squash

Management Practice Avoid working when leaves

are wet Avoid overhead irrigation Crop Rotation Destroy crop residue Encourage air movement Plant disease free &

resistant plants

BACTERIAL BLIGHT Symptoms

Large, brown, circular spots on leaves & bean pods

Lesions may be surrounded by a yellow halo

Management Practices Avoid working when leaves

are wet Avoid overhead irrigation Crop rotation Destroy crop residue Encourage air movement Plant disease free &

resistant plants

POWDERY MILDEW Symptoms

Small, round & whitish spots on the lower leaves

Management Practices Encourage air movement Plant resistant cultivars

Conditions Favorable for Development

Cool, moist conditions Time of Year it Appears

March thru September

DOWNY MILDEW Symptoms

Yellow to brown spots on the upper surfaces of leaves

Fuzzy white patches on the fruit

Infected leaves may die

Effects beans, cucumbers & melons

Management Practices

Rotate Crops Plant resistant varieties Spray fungicides

FUSARIUM WILT Symptoms

Plants wilt, turn yellow and die (starts from bottom)

Often confused with lack of water

Cucumber, squash, broccoli, & cabbage is also affected

Management Practices Plant resistant varieties Rotate crops Remove and destroy

plant

MOSAIC VIRUS Symptoms

Leaf blades become long & skinny

Leaves may be mottled Cucumbers, squash &

beans are affected Management

Practices Control aphids

COMMON PESTS IN THE VEGETABLE GARDENPESTS

JAPANESE BEETLE Damage

Adults Eat flowers Skeletonize leaves of a broad

range of plants Larvae

Feeds on roots of lawn grasses & vegetable plants

Management Practices Hand pick and place in bottle

with soapy water Cover plants with floating row

cover Apply parasitic nematodes to

sod to kill larvae Parasitic wasps & flies

Grow borage as a trap cropWhite geranium, garlic & rue are RepellentsLarkspur not only attracts them, but it isFatal to them.Apply milky spore to your lawn to kill the grubs

REDBANDED LEAFHOPPER Damage

Adults & nymphs suck juices from stems & undersides of leaves of most fuit & vegetable crops

Toxic saliva distorts & stunts plants

Causes tipburn & yellowed, curled leaves with white spots on undersides

Spread viral diseases as they feed

Wash plants with stiff sprays of water

Spray with insecticidal soap Last resort spray with neem

or pyrethrin

APHIDS Usually green although some

species are yellow, pink, brown or black.

Most prevalent during cool, dry weather on small plants.

They suck the plant sap, causing foliage to distort & leaves to drop.

Feeding spreads diseases. Treatments for aphid control should

begin at any time colonies are found.

Spray foliage with soapy water, then rinse with clear water or use insecticidal soaps.

Once the weather warms up, natural enemies usually control aphids

CORN EARWORM Affects tomato, pepper, beans,

cabbage and corn. Plant corn as early as possible Apply mineral oil on corn silks

five to six days after silk emergence.

Mixing a Bacillus thuringiensis (B.t.) product with mineral oil can improve control of earworms. With liquid B.t. products, use a ratio of 1 part B.t.to 20 parts oil. One application of ¼ teaspoon or five drops of the oil mixture should be applied to the silk at the tip of the ear.

CUTWORM They chew through stems at ground

level May completely devour small plants Most damaging in May & June Place a collar of stiff paper, cardboard,

or aluminum foil around each plant for protection after transplanting to the garden.

At the first sign of cutworm moths, spray the plant stems and leaves with Bacillus thuringiensis (B.t.) to kill the larvae.

A bait can be made by mixing B.t. with bran until the liquid is absorbed by the bran, and then adding a small amount of molasses. Crumbled pieces can be scattered around the base of the plants to protect them. Cultivating the soil can kill cutworms.

MEXICAN BEAN BEETLE Adults and larvae chew on

leaves from beneath, leaving a lacy appearance

Plants are defoliated & killed Since most damage occurs

during July and August, quick-maturing varieties of green beans planted very early or during late summer may escape damage.

Handpick and destroy beetles and egg masses.

Spray with neem

SPIDER MITE Adults and immature stages appear as

tiny specks on the undersides of leaves where they pierce the leaf surface and suck sap.

Lightly infested leaves develop tiny whitish speckled spots, while heavily infested leaves turn pale yellow or bronze-colored and dry up.

The undersurfaces of leaves usually are covered with silken webs over which the mites crawl.

Spider mites develop rapidly during hot, dry weather and one generation can be completed in as few as eight days.

Insecticidal soaps generally offer adequate control when applied before the numbers are too high. Mites can be removed with a strong spray of water. Natural enemies such as lady bugs are important natural controls.

STINK BUG Stink bugs feed on over 52 plants,

including native and ornamental trees, shrubs, vines, weeds and many cultivated crops

Nymphs and adults of both kinds of bugs pierce plants with their needlelike mouthparts and suck sap from pods, buds, blossoms and seeds.

The degree of damage depends, to some extent, on the developmental stage of the plant when the stink bug pierces it. Immature fruits and pods punctured by bugs become deformed as they develop. Seeds are often flattened and shriveled, and germination is reduce

Insecticides such as permethrin, effective in controlling stink bugs.

CUCUMBER BEETLE Harmful to cucurbits (members of

the gourd family, including cucumbers, melons, pumpkins and squashes), particularly young plants.

They feed on plants as soon as they emerge and either kill the plants or greatly slow their growth.

Transmits bacterial wilt of cucurbits.

Control measures include the use of fabric row covers.

Handpicking to remove the beetles is effective.

Eliminate weeds in and around the garden.

Last resort apply pyrethrins

FLEA BEETLE Adults chew numerous small,

round holes in leaves Larvae feeds on plant roots Most damaging to young

plants Adults are very small (1/16

inch or so) black or dark brown insect

Severe infestations stunt plants and reduce yields

Apply floating row covers Apply parasitic nematodes to

soil Spray neem

CABBAGE LOOPER Feeds on cabbage, broccoli &

cauliflower Young larvae feed between veins on

the underside of the lower leaves. Large larvae make ragged holes in the foliage and move to the center of the plant.

Large loopers can also burrow through 3 to 6 layers of tightly wrapped head leaves in cabbage.

Plants can be severely defoliated and stunted, producing no heads or becoming unfit for consumption.

Large amounts of dark green pellets excreted by the feeding

Bacillus thuringiensis, Bt can be used along with row covers and diamaceous earth

HARLEQUIN BUG Feeds on squash, corn,

bean, asparagus, cabbage, okra, and tomato

Adults and nymphs pierce stalks, leaves, and veins with their needle-like mouthparts and extract plant juices.

Stems and leaves injured in this manner develop irregular cloudy spots around the puncture wound.

Control by handpicking or using insecticidal soap

WHITEFLY Feeds on bean, melon, lettuce,

cucumber, tomato, squash, potato, eggplant, strawberry

Nymphs and adults extract plant sap through their needle-like mouthparts, the adults preferring to feed on tender new growth.

Leaves turn yellow and drop from infested plants.

Spray with insecticidal soap Check plants bought from the

nursery Nasturtiums & marigolds repel

them

COLORADO POTATO BEETLE Serious pest of tomato, eggplant,

peppers & potatoes Notorious for its ability to rapidly

develop resistance to insecticides that are used repeatedly for control

Bacillius thuringiensis (Bt) is effective against small larvae (less than 1/4 inch) and should be applied at egg hatch or when larvae are first seen

Hand picking of adult beetles and immature stages is encouraged Hand picking can be particularly effective in reducing the numbers of overwintering beetles coming to the young plants in the spring

Floating row covers

SQUASH BUG Radishes, tansy,

marigolds & nasturtiums interplanted with squash help repel

Trellising gets foliage off the ground, reducing the moist, covered areas they seek

Squash plants frequently are killed by this sap-feeding pest. Leaves wilt rapidly and become brittle.

Adults and nymphs may be found clustered about the crown of the plant, beneath damaged leaves, and under clods or any other protective ground cover.

This can be used to your advantage in controlling these pests. Place a small, square piece of old shingle or heavy cardboard under each squash plant. As bugs congregate under it for protection, simply lift the trap and smash them with your hoe (or shoe).

Other control methods include early planting and removing eggs and nymphs by hand.

SQUASH VINE BORER Radishes

interplanted helps repel them

Damage is caused by larvae (immature forms) tunneling into stems. This tunneling often kills plants

Sudden wilting of a vine and sawdust-like insect waste coming from holes in the stem are evidence of attack

Till the soil in late winter to expose overwintering insects.

Rotate squash to another location in the garden each season.

Destroy vines that have been killed to break the life cycle.

Cut a slit along afflicted stem and remove the borer or inject the stem with Bt

THE GOOD GUYS

LADY BUGS Feed on small, soft

pests such as Aphids Mealybugs Spider Mites

Purchase the larvae not the adult

LACEWINGS Feed on the

following: Aphids Caterpillars Small beetles Leafhoppers Thrips Mites and they

sometimes eat each other

PARASITIC WASPS Injects its eggs

inside host insects Controls the

following Aphids Whiteflies Caterpillars

SOLDIER BEETLE Larvae feed on

insects in the soil Adults feed on

caterpillars, aphids And other soft

bodied insects

PEST & DISEASE PREVENTION Grow strong, healthy plants that can resist attack

Starts in the nursery Pest & Diseases prefer plants that are weak and injured

Plant in fertile soil Plants are able to find the nutrients easily in healthy soil

Daily Vigilance Check your garden daily Be careful when handling plants. Do not damage the stems or

leaves. This will stress the plant and weaken them. Plants are like humans

Never let them go short of food or water Sanitation

Disease-causing organisms can live through the winter Equipment used on diseased plants should be washed with a bleach solution

PREVENTION CONT’D Rotate Crops Avoid Monocultures

Don’t just plant one variety in a large area. Diversity

Encourage Natural Predators Plant Resistant Varieties Use Barriers

Floating Row Covers Bird Netting

ORGANIC CHEMICALS FOR PEST CONTROL Even though they are organic follow the instructions on

the label Spray when bees are not active Types:

Insecticidal Soap Potassium-salt soap Control can only be achieved by hitting the insect

Bt (bacillus thuringienses) Bacteria that produces crystals & spores that paralyze the digestive

tract Nontoxic to mammals

Neem Broad spectrum Nontoxic to mammals

REFERENCES Southeastern US 2011 Vegetable Crop Handbook www.utextension.utk.edu http://vegetables.tennessee.edu Organic Gardening

Geoff Hamilton Bugs, Slugs, & Other Thugs

Rhonda Massingham Hart All-New Encyclopedia of Organic Gardening

Rodales The Organic Gardener’s Handbook of Natural Insect & Disease

Control Barbara W. Ellis & Fern Marshall Bradley

Rodale’s Garden Problem Solver Jeff Ball