Eliminating Pests and<br>Insects In The Strawberry Patch

Eliminating Pests and<br>Insects In The Strawberry Patch

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Eliminating Pests and<br>Insects In The Strawberry Patch

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Eliminating Pests and<br>Insects In The Strawberry Patch

Eliminating Pests and<br>Insects In The Strawberry Patch

Eliminating Pests and<br>Insects In The Strawberry Patch
Eliminating Pests and<br>Insects In The Strawberry Patch
Eliminating Pests and<br>Insects In The Strawberry Patch

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Online Magazine

Eliminating Pests and
Insects In The Strawberry Patch

By Robert Laurence

Follow these general sanitary practices and you'll have little trouble with insect pests and diseases in the strawberry patch:

* Don't plant strawberries in an area where any crop has grown for the past 2 to 3 years if possible; definitely don't plant them where members of the tomato family have grown for 2 to 3 years.

* Choose a weed free site or rid the area of all weeds

* If planting on a lawn, turn the lawn over at least a year beforehand to rid the area of any grubs possibly feeding at grass roots.

* Buy only registered, virus free (VF) plants, which are widely available from nurseries. Such plants, introduced by the USDA, have made serious virus diseases in strawberries a thing of the past.

* Purchase disease resistant plants whenever possible, and buy varieties recommended for your area, especially if diseases are a problem there.

* Buy from a nursery whose stock is frequently inspected by state plant inspectors and is certified apparently free of diseases and insect pest infestation.

* If plants you purchase appear to be infected in any way, don't plant them. Send them back to the nursery, or write a letter of complaint asking the nursery to rectify the situation.

* Keep the garden clean and destroy all plants that become infected with incurable diseases.

* Move the strawberry patch to a new location every 3 to 4 years to discourage insect pests or disease buildup in the soil.

Despite all the precautions above, you may have some trouble with insect pests and diseases. The two following lists give descriptions of common strawberry pests and diseases, including symptoms and suggesting various remedies, where there are any.

A List of Strawberry Insect or Animal Pests and Controls

BIRDS - Leave ripe berries unattended and birds will make a meal of the patch before you can pick it. There are numerous ways to protect against them. Often a transistor radio left playing in the garden will scare birds off. Records of bird distress signals, timed fireworks, and various commercial noisemakers have proved successful in some cases. White string wrapped around plants apparently resembles spider webs to birds; they mistake pieces of rope or garden hose for snakes; and broken mirrors, aluminum pie plates, or streamers of cloth or aluminum foil hung in the garden sometimes scare them off, too. Yet these controls, like the time honored scarecrow, soon become so familiar to the feathered felons that they become contemptuous of them. Volch oil sprayed on berries does keep birds away, but the very best control is to cover the strawberry bed with cheesecloth, clear plastic, or even old nylon curtains when the berries begin to ripen. Be sure to weight the covering down with boards, bricks, or rocks. The wind can blow it away otherwise and I have seen birds actually pull unweighted cheesecloth aside to get at berries.

CROWN BORER - Adults are small, brownish, red snouted beetles that feed on foliage and berries. Larvae are little white legless grubs, curved and plump, that tunnel through the crowns, cutting off plants. The chemical control is to dust with chlordane around the crowns before the blooming period. Organic control is to destroy the infected bed and start a new one at least 300 feet from it.

CUTWORM - Fleshy green to black striped worms that cut young plants at ground level. Chemical control is usually dusting the ground with chlordane before planting. Organic controls are many and include: 1) placing cardboard collars around plants so that cutworms can't reach them; 2) scattering mothballs or blood meal around to repel cutworms; 3) digging up the ground in early spring to expose and kill cutworms; 4) lining boards over dampened soil to lure cutworms underneath them where you can destroy them; 5) spraying with the biological insecticide Bacillus thuringiensis.

CYCLAMEN MITES - Barely visible white, green, or brown mites which feed at the base of plants on leaves and flowers, destroying both. Newly expanding leaves may turn brown and die. Older foliage turns dark green with a puckered, twisted appearance and plants can be stunted, producing few runners and less fruit. Serious infestations of these mites in the first year often result from infested stock bought from nurseries - all the more reason to deal with a trusted supplier, for the grower can't tell whether or not there are eggs in the unopened leaves and plant crown when buying the plants. Chemical control is to spray with malathion, but this may kill the predatory insects that usually keep mites in control. Try spraying with safe rotenone, a commercial preparation made from tropical plants. Spraying plants forcibly with water is a control worth a try, but try to hit the undersides of the leaves.

LEAF APHIDS - Small greenish plant lice that travel from plant to plant and transmit virus diseases. Like the root aphid they are transported by ants. Use the controls for the Strawberry Root Aphid, below.

LEAF TIERS - Large, pale greenish yellow worms striped lengthwise with green and white. They curl up leaves, which they feed on and web together. Try dusting with safe pyrethrum twice in a half hour when first noticed.

NEMATODES - Nematodes are microscopic "eel worms" that live in the soil. The root knot nematodes form swellings or galls in strawberry plant roots, weakening and stunting the plants, which produce few runners and have lower yields. Root lesion nematodes enter and feed on strawberry roots, leaving wounds where soil fungi may enter and cause extensive rotting, making the plants less productive and sometimes killing them. Both of these nematodes cause more severe damage in light, sandy soils. The only chemical control is to fumigate the soil, an expensive, dangerous operation. Organic ways are plentiful, effective, and much safer. They include:

* Rotating crops so that nematodes don't have a chance to build up in the soil.
* Keeping the soil well supplied with humus by digging in organic matter.
* Using a repellent mulch (grass, decayed leaves, or water hyacinths) that encourages the growth of fungi that attacks the nematodes.
* Planting African marigolds near the strawberries. These exude a substance from their roots that will repel nematodes a year after planting.
* Placing slices of the wild or mock cucumber (Echinocystis lobata) around the plants to repel nematodes, or soaking the soil with water that asparagus has been cooked in. The USDA has even found that 5 pounds of sugar mixed with 100 pounds of soil will kill all nematodes within 24 hours.

RABBITS - Eat leaves of young plants. Sprinkle blood meal mixed with a gallon of water around the garden, or use Epsom salt sprays, or mothballs. A bucket of hot water in which a chunk of liver has been soaked for thirty minutes is also said to make a good rabbit repellent spray. Some gardeners bury bottles filled with water around the garden, just the bottle necks sticking out of the ground the lights reflected off the glass or the wind whistling over the bottles scares the rabbits.

RED SPIDER MITES - Minute reddish green mites that suck juices from leaves, causing them to brown or yellow, and spin a thin web over leaves. Plants become generally unhealthy. Chemical control is spraying with malathion. Try a jet of plain water aimed at the mites, or spray with safe rotenone.

ROOTWORM - Small, chunky, copper colored beetles which feed on foliage, their white, brown spotted grubs feeding on roots. Both weaken the plants. Chemical control is dusting with chlordane before planting.

ROSE CHAFER - Medium-sized, yellowish, long-legged, clumsy beetles that eat foliage and blossoms. Their whitish grubs attack roots. Chemical control is to dust with a rose dust or all around dust before buds open. Or try handpicking the beetles.

SLUGS - Large, slimy, soft bodied, snail like forms that feed at night. Not a major strawberry problem, but sometimes they will eat foliage and fruit. Slugs hide under rocks, boards, mulch, and other objects in the daytime and travel at night at the rate of a mile in eight nights. There are many, many controls:

* Frequently inspect under mulch and collect slugs, destroying them by dropping them into kerosene..
* Place boards or cabbage leaves in the garden to attract and collect slugs.
* Turn over soil in early spring to expose and kill slug eggs.
* Put down coarse, scratchy mulches like hay, which slugs dislike..
* Use new products like Snail Snare, which dehydrate and kill slugs rather than poisoning them.
* Collect slugs with baits like commercial methaldehyde and destroy them.
* Collect and destroy slugs with shallow pans of stale beer. Slugs will crawl into the pans at night and drown. Other similar homemade solutions include grape wine, blackberry wine, vinegar, and a tablespoon of flour and 1/8 teaspoon of yeast mixed with a cup of water.

SNAILS - Same controls as for Slugs, above.

SPITTLEBUG - Immature forms live in a mass of froth or spittle attached to plants. Adults are grayish, frog shaped bugs that fly about. Spittlebugs suck the sap from foliage and weaken plants, the fruit on infested plants often small and of poor quality. Control is seldom necessary except when infestation is heavy. Chemical control is dusting with an all around dust. Try hand picking.

SQUIRRELS - Should squirrels be a nuisance rooting around in the patch for buried nuts or bothering berries, you can sprinkle mothballs or similar commercial preparations around the plants. This will repel squirrels to a degree.

STRAWBERRY LEAFROLLERS - Small green or brownish caterpillars which first occur on the undersides of leaves, then roll or fold the leaves up about themselves. The rolled leaves, fed upon by the insect, turn brown and die, damaging the plants and decreasing the crop. The white web of the leaf roller can be seen inside the rolled leaves. Chemical control is spraying with Sevin. Try handpicking or spraying with harmless rotenone.

STRAWBERRY ROOT APHID - Small blue-green, soft-bodied plant lice that first appear on the leaves and are later carried to the roots by ants. They suck out plant juices and weaken plants. Chemical control is to dust soil with chlordane before planting. The organic ways are numerous, including methods designed to eliminate the ants, which keep aphids as "milk cows," transporting them around for the sweet secretion they exude. Organic controls for aphids include:

* Planting strawberries in rich humus soil, which aphids avoid. .
* Placing aphid-repelling nasturtiums, garlic, chives, or rhubarb near strawberries.
* Washing the aphids off plants with water or a solution of soapy water.
* Using the biological spray Basic H made from soybeans, or the safe insecticides rotenone and pyrethrum.
* Sprinkling bone meal around the holes of the ants that carry aphids.

STRAWBERRY ROOT WEEVIL - Also known as the "clipper," this is a small, short snouted beetle, reddish brown to almost black, that feeds on leaves and berries. Its larvae are white, legless, curved grubs that feed in the crowns. The adult hibernates under the mulch or under plant debris and appears on plants at blossoming time, the female depositing an egg in a bud and then cutting the stem so that the bud falls off or hangs suspended by a few threads of plant tissue. Over half the buds in a bed can be destroyed. Chemical control is chlordane dust applied to the soil before planting. The only good organic control is to plow up the bed after harvest every year and start a new bed more than 300 feet away. This will prevent buildup of the pests.

TARNISHED PLANT BUG - A small brown sucking insect that severely reduces the quality and quantity of strawberry yields, especially of Everbearers, which mature in late season when the pest is most active. Injury in berries results from feeding punctures made before the straw berries are ripe. The affected "button fruit" is small and deformed at the tip, the seeds crowded together. (It should be noted, however, that many factors that prevent proper pollination can also cause deformed fruit, even inclement weather.) Chemical control is to spray with malathion or Sevin, or dust with an all around dust. Also try handpicking the insects.

TWO SPOTTED SPIDER MITE - A barely visible insect varying in color from pale greenish yellow to dark crimson, usually with one dark spot on each side of the body. These mites suck juices from the leaves and if uncontrolled seriously retard plant growth and fruit production. Control as with Red Spider Mites, above.

WHITEFLIES - Little white moths that flutter out when disturbed and thus are often called "flying dandruff." Their larvae feed on the undersides of leaves, weakening the plants. Chemical control is spraying with malathion. Effective organic controls are garlic sprays, and planting mint or tansy in the garden to repel the flies.

WHITE GRUBS - Adults are large June beetles. The larvae, which make all the trouble, are big, plump, yellowish white, curled grubs in the soil that feed heavily on strawberry roots and can seriously damage them. Do not plant strawberries in ground that was sod the previous year. Wait at least a year after turning over the sod. If you do plant immediately after sod has been turned over, use a soil insecticide first. Chlordane applied to the soil before planting is the usual choice.

WIREWORMS - Soil infesting, cylindrical, yellow to brown, hard shelled, shiny, jointed worms up to 1 1/2 inches long that feed on plant roots. Organic control is not to plant strawberries after soil has been in sod - wait at least a year after turning under the sod. Enriching soil with humus also helps, as does good drainage and planting turnips or radishes as trap crops to collect wireworms. The worms will gravitate to the turnips or radishes and can be easily collected just by pulling up the roots.

A List of Strawberry Diseases and Controls

BLACK SEED - See Leaf Spot, below.

BOTRYTIS FRUIT ROT - Commonly called gray mold or brown rot, this is the most serious and widespread of the half dozen or so rots that attack strawberries. It first appears as a light brown spot on green or ripe berries and progresses through the fruit. Later, the entire berry becomes brown and rotten. During wet periods a gray dusty fungus covers the infected fruit. The fungus spores of botrytis rot are easily detached and carried to berries nearby by air currents and splashing water. Good gardening practices will therefore reduce losses. These include spacing plants adequately; maintaining a narrow matted row; keeping the planting weeded; irrigating only when conditions favor rapid drying; and using mulches that prevent the berries from touching the soil. Also avoid the use of nitrogen fertilizer during the spring before the harvest season. Nitrogen induces dense foliage and tends to soften fruit, making it more susceptible to the disease. Some organic growers claim that the use of dolomitic limestone and colloidal phosphate eliminate botrytis fruit rot. Chemical control is spraying with a fungicide.

BROWN ROT - Same controls as for Botrytis Fruit Rot.

DWARFING - Caused by microscopic roundworms which live between the folded young leaves and suck out sap, resulting in dwarfing and wrinkling of new leaves. Occurs in the southern United States. Control is not to plant new beds in old soil and to rogue out all infested plants and destroy them.

GRAY MOLD - Same controls as for Botrytis Fruit Rot.

LEAF SCORCH - Irregular, dark purple spots without gray centers characterize this fungal disease. Attacks old as well as new growth, and attacks all parts of the plant above ground. Same controls as for Leaf Spot, below.

LEAF SPOT - Only new growth is susceptible. Appears on leaves as purple circular spots with gray centers. The disease also occurs on berry caps, leaf and fruit stalks, and on the berries themselves, where it turns one or several seeds of the berries brownish black and is called black seed or black berry. Abundant moisture encourages the development of the disease. Organic protection is essentially the same as for Botrytis Fruit Rot, above. Chemical control is spraying with fungicides. The varieties Catskill, Premier, Midway, and Robinson are resistant to leaf spot. Very susceptible varieties are Jerseybelle, Pocahontas, Redglow, and Sparkle.

POWDERY MILDEW - Leaves curl upward and there is a white cobweblike growth on the lower surface of the leaves. The disease often occurs during extended periods of cool weather in the growing season and is not as damaging as it is unsightly. Control is to plant resistant varieties like Catskill, Empire, and Sparkle. Dixieland, Midland, Redglow, Stelemaster, and Jerseybelle are very susceptible to powdery mildew.

RED STELE DISEASE - A fungus disease that attacks the roots of plants. Plants become stunted, older leaves die, new leaves turn small and bluish, fibrous roots decay, main roots rot, and the central part or "stele" of the root turns dark red. The plants rarely produce a normal crop. Very susceptible varieties are Dixieland, Earlidawn, Pocahontas, Armore, Midway, Jerseybelle, Midland, Redstar, Daybreak, Lassen, Northwest, Vesper, and Raritan. Avoid planting red stele infected stock. There are red stele resistant varieties, including Redcrop, Sparkle, Stelemaster, Surecrop, Temple, and Vermillion.

VERTICILLIUM WILT - This common soil borne fungus disease attacks the leaves and vascular system of the plants, weakening them and decreasing their yield. The earliest symptom is wilting and dying of the older outer leaves. Younger leaves become paler and begin to curl upward. Finally, the entire plant may collapse and die. Chemical fungicides do little good here because this fungus lives so long in the soil. Controls are to plant in ground free of the verticillium fungus. Never plant strawberries on land where tomatoes, peppers, potatoes, eggplants, or other strawberries have been growing for the last two years - for the fungus increases tremendously in their presence. Keep the garden clean and don't dig any of the above plants or their fruits into the sod. Varieties highly resistant to verticillium wilt include Catskill, Empire, Erie, Frontenac, Fulton, Premier, Surecrop, and Vermillion. Moderately resistant varieties are Fletcher, Blakemore, Guardian, Marshall, Sunrise, Tennessee Beauty, Salinas, and Robinson. Very susceptible varieties are Dixieland, Earlidawn, Pocahontas, Armore, Midway, Jerseybelle, Midland, Redstar, Daybreak, Lassen, Northwest, Vesper, and Raritan.

VIRUS DISEASES - A great many virus diseases attack strawberries, some of them producing clear symptoms such as mottling (spotting or blotching) of leaves, and others producing no visible symptoms. Plant vigor is affected, fruit yield is lowered, and plants cannot be cured once infected. Since most strawberry viruses are carried by aphids, they are best controlled by controlling the aphids. But if the gardener buys virus free (VF) straw berry plants developed by the USDA there is little to worry about concerning virus diseases. Such plants are offered by almost every nursery today. If the plants catch a virus in the garden, however, precautions do have to be taken against the aphids.

YELLOWS - A heredity defect, not a virus disease, that is also called Spring yellows and June yellows. Plants are stunted and yellow. Affected plants usually occur together in spots or rows. Their leaves are rounded, often cupped or twisted, and have yellow margins. The plants never recover and bear less fruit than healthy plants. Certain varieties, such as Diamond and Earlidawn, are very susceptible.

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Eliminating Pests and
Insects In The Strawberry Patch