Here is a list of twelve major garden pests. Also learn about how to control them!
1. The Japanese Beetle:
The Japanese beetle is a foreigner who has found conditions to his liking in the eastern United States and is continuously expanding his domain. He can be easily recognized by his shining, metallic green body, coppery brown wings, and fine white patches along each side of the body.
The beetles are voracious feeders, attacking a large number of plants, but showing a decided preference for some. A list of preferred and rarely attacked vegetables and fruits is given so that certain highly preferred varieties may be protected or avoided in heavily infested areas.
Control:
Repellent sprays are the only ones that have been found successful in preventing injury to foliage and fruit. A number of effective commercial preparations are on the market or you may mix your own.
1. Lead Arsenate Spray:
Lead arsenate – 11 tbsp.
Wheat flour – 5 tbsp.
Water – 2 gal.
2. Lime Spray:
Hydrated lime – 2 cups
Raw linseed oil – 1 tbsp.
Water – 2 gal.
3. Rotenone Spray (When Restrictions are lifted):
Ground Derris, cube or timbo powder (containing at least 4% rotenone) – 8 tbsp.
Raw linseed oil – 1 tbsp.
Water – 2 gal.
In formulas 2 and 3 the powder should be dispersed in water first before adding the oil.
The lead arsenate spray should be used only on trees without fruit or after the fruits have been picked. The non- poisonous lime spray may be used on fruits and vegetables, and likewise the rotenone spray when restrictions as to its use are lifted. The sprays should be applied thoroughly to the foliage and fruit at intervals of two to three weeks, beginning near the end of June when the beetles first appear. The amount of rainy weather may make more or less sprays necessary. Rotenone sprays have to be applied at weekly intervals to keep their effectiveness.
4. In the home garden the preferred vegetables can be protected from Japanese beetles by dusting them thoroughly and often with a good grade of fine hydrated lime.
5. To protect the silks of sweet corn from the beetles, the tips of the ears should be dusted before the beetles accumulate with a very finely ground hydrated lime as soon as the silk appears. This should be followed by two more applications at three-day intervals. Injury to silks by the beetle prevents the formation of kernels.
6. On grapes, a continuation of the regular Bordeaux-lead arsenate spray is effective.
7. Japanese beetle traps with yellow baffles and baited with a mixture of geranial and eugenol may be used effectively in light infestations to supplement the use of repellent materials. For best results, they should be placed 5 to 10 feet from the plants to be protected, and not more than 3 feet above the ground.
2. White Grubs:
The larvae of several beetles, including the Japanese beetle, live in the soil and are known as white grubs. They feed on the roots of plants, and when present in a garden may do considerable damage to die roots of strawberries, beets, onions, and beans.
Control:
1. Heavily infested sod land should not be used for a garden the first year unless it is plowed up late in the fall and the soil carefully worked in the spring so that most of the surviving grubs can be found and killed. Even then enough grubs may escape to cause trouble.
2. In small areas soil fumigation may be practiced effectively. The soil should be prepared for planting and a soil fumigant, such as ethylene dichloride emulsion or carbon bisulfide emulsion, should be applied according to the directions with the container.
Ethylene dichloride emulsion has recently been found very effective against Japanese-beetle grubs when diluted at the rate of 1 gallon to 100 gallons of water, or 2 ½ tablespoonfuls per gallon of water, applied at the rate of 1 gallon per square yard with a sprinkling can, and watered in well. Negligible injury was also reported when this treatment was made on turf and to soil surface above the roots of plants.
3. Since it has been determined that lead arsenate in the standard dosage (10 pounds per 1,000 square feet) for grub control on lawns will not affect the growth of most vegetables and will not make vegetables grown on treated soil dangerous to health, there is no reason why garden soils heavily infested with grubs cannot be successfully treated in the fall or early spring with lead arsenate, applied evenly at the rate of 5 pounds per 1,000 square feet of space. The lead arsenate may be watered in or raked into the top few inches of soil.
4. Recently a bacterial disease of the Japanese beetle grub, known as the Milky Disease, has been offered for sale in powder form in some horticultural supply houses. This disease was first produced and distributed by the U. S. Bureau of Entomology through various state agricultural agencies, which applied the disease spores to soil in heavily infested areas. The commercial production of this disease, if carefully supervised and licensed, should be as effective a material as that made by the Bureau of Entomology or State Experiment Stations.
The disease remains permanently in the Soil, and in several years’ time gradually reduces grub populations. It is not harmful to plants, animals, or humans. The Milky Diseases have also been found to infect some grubs other than those of the Japanese beetle and may help in eliminating them also.
3. Wireworms:
Gardens located on land that had been in sod the previous year may also be heavily infested with slender, hard, orange-brown larvae which develop into click beetles. The wireworms are especially fond of potatoes, carrots, beets, sweet potatoes, and onions. They burrow into roots or tubers while feeding and are frequently found partly embedded in the tissues.
Control:
1. Soil fumigation before planting, may be used to destroy the wireworms.
2. When injury is discovered after the plants are in, one of two methods may be employed. The first method consists of burying to a depth of about 4 inches pieces of potato throughout the garden and marking each spot with a stick.
These potatoes should be dug up at weekly intervals, and all wireworms found should be killed.
3. The second method consists of soaking the soil at the base of the plants with a water solution of a relatively new fumigant, dichloroethyl ether. Two tablespoonfuls of dichloroethyl ether are thoroughly shaken with a gallon of water, and the resultant mixture applied at the rate of pint per plant, or a quart per linear foot of row. Plants are not injured by this treatment, which may also be effective against other soil-inhabiting insects.
4. Cutworms:
Many a gardener has gone out to examine his flourishing garden in the early spring, only to find many young plants, such as peppers, cabbages, tomatoes, and eggplant, mysteriously clipped off at their base. This injury is caused by smooth, fleshy, grayish or brownish caterpillars, which roll their bodies in a tight curl when disturbed. They carry on their activities at night only, and during the day hide in the soil, usually near the base of the plant attacked.
Control:
1. Inspecting the soil to a depth of an inch or two near the base of plants attacked will uncover many of the culprits.
2. Stiff 2-inch or 3-inch paper collars, tied loosely around the stems of plants attractive to cutworms and pushed about ½ inch into the soil, are excellent and cheap guards against cutworms in small gardens.
3. The best remedy for cutworms in larger gardens is the poisoned bait recommended under Stomach Poisons.
This formula is best made up in the morning and applied in the evening by scattering it thinly over the garden or about the bases of plants that have been set out. The first treatment should be made a day or two before any plants are set out and should be repeated if injury to plants occurs at a later date. Children, animals, and poultry should be kept away from treated fields, as the bait is poisonous.
5. Ants in Your Garden:
In gardens where the soil tends to be light or sandy, ants may be a serious problem because their numerous tunnels near the bases of plants cause drying of the roots, especially during hot, dry weather. In addition, some species of ants harbor foliage and root aphids, and still others have been observed to chew on the bases of young seedling plants and kill them.
Control:
1. The most recent and simple method of ant control consists of the use of sodium fluoride. This material, applied as a dust with die aid of a hand duster to the surface and openings of nests, has been found to give complete control within a few days. It may be used safely with growing vegetables if care is taken not to get any of the material on the foliage.
2. Another method consists of the use of cyanogas to fumigate the ants in their tunnels. Directions on the container should be carefully followed. This method may result in injury to living plants if the tunnels are near the roots.
3. Poison baits containing thallium sulfate may be used according to directions without danger to plants, but with some danger to humans and animals.
6. Garden Slugs:
During rainy seasons or in gardens situated in moist locations, grayish, sometimes spotted, slimy, legless creatures known as slugs often do considerable damage by eating ragged holes in the leaves of such plants as lettuce, cabbage, beans, radishes, and peas. These pests hide during the day under plants and garden debris, but come out at dusk, crawl onto the plants and feed on the foliage.
Control:
1. Inspecting the plants at night with the aid of a flashlight will reveal the slugs at work. At this time they can be collected and destroyed.
2. A very effective bait has recently been developed which not only kills the slugs when they feed upon it, but also attracts them. Methaldehyde is the poisonous ingredient in the bait, which may be obtained in horticultural supply stores under several trade names. The bait is placed in small heaps at intervals in the garden.
7. Aphids or Plant Lice:
The tiny, soft-bodied insects which suck the sap from plants are referred to as aphids or plant lice. There are a number of species, each one favoring a particular crop. Most species of these tiny pests are some shade of green, but nearly every color of the rainbow may be found among this prolific tribe. They are usually found clustered on the growing tips of plants or on the undersides of the foliage, where their sap-sucking causes curling, wilting, or death of the parts attacked.
They excrete a sweet, sticky substance on the leaves called honeydew, which attracts ants and on which a sooty fungus may grow, discoloring the foliage. Aphids give birth to living young all summer long, but many species produce overwintering black, shiny eggs in the fall.
Control:
1. Any good contact dust or spray, such as nicotine sulfate, pyrethrum, or rotenone, is effective against most aphids if they are hit by the material. It is essential to direct the spray or dust to the undersides of the leaves, where the majority of the aphids are, in order to obtain good control. Get the aphids before leaf-curling starts, as it is almost impossible to reach them in the curled leaves.
2. Root aphids are much more difficult to control. Their presence may be indicated by large numbers of ants tunneling about the base of the plants attacked. The dichlor- ethyl-ether treatment suggested for wireworms should be effective against root aphids, as well as the ants.
8. Nematode Worms or Eelworms:
Tiny microscopic worms, known as nematodes or eelworms, sometimes become established in garden soils and cause irregular swellings on the roots of nearly all garden vegetables and some nuts and fruits by burrowing into them. Tubers and storage roots are also attacked and show brown spots beneath the skin. This injury causes a reduction of yield in some plants, and stunting and death to others. Be careful not to confuse this injury with the nodules caused by beneficial bacteria on beans, or the clubroot disease of cabbage and related crops.
Control:
1. In small garden areas this pest may be eradicated by fumigating the soil with chloropicrin (Larvacide) according to directions obtained with the container. Holes 10 inches apart and 4 to 5 inches deep are made with a stick and ½ teaspoonful placed in each hole. The holes should be covered over and the top few inches of soil wetted. In addition, it is preferable to cover the treated area with mulch paper or damp canvas for two days. At least ten days should elapse before any planting is done on treated soil.
2. Selection of an uninfested site for the garden and crop rotation are the only alternatives to fumigation. Planting immune or resistant varieties in the infested area for one, or better two, years and keeping all weeds down will usually reduce the nematode population so that susceptible vegetables may be planted for one year without serious injury. Immune varieties of plants are corn and other grains, and nearly all grasses.
9. Flea Beetles:
One of the earliest pests to appear in the garden is the tiny, dark flea beetle, which jumps like a flea when disturbed. Flea beetles pepper the leaves with tiny holes and may severely injure young plants. The preferred plants are eggplants, potatoes, tomatoes, radishes, cabbages, and beans, although they may be found on numerous other vegetables and fruits.
Control:
1. Young plants should be dusted frequently with a rotenone, pyrethrum, or cryolite dust when the beetles begin to appear in numbers, usually shortly after early tomatoes are set out in the garden. Rotenone dust is most effective, but the other two materials mentioned are good substitutes. Be sure to cover the undersides of the foliage, as that is where most of the beetles feed. The flea beetles disappear after about a month, but a second generation appears later in the summer and harms plants at that time.
2. On potatoes, Bordeaux mixture or copper-lime dust applied thoroughly are effective repellents.
10. Red Spiders or Mites:
During hot, dry summers, many vegetables and fruits are attacked by tiny, reddish mites or spiders, which suck the juices from the leaves and cause them to become rusty or yellowed and seriously weaken the plants. A close inspection of the undersides of infested foliage will disclose the tiny mites, their very fine webs, and their glistening spherical eggs.
Control:
1. Watch for the whitish speckling or curling of older leaves, as this is the first indication of a mite invasion. Dust at once with a fine dusting sulfur, directing the dust mainly to the undersides of the foliage. A wettable sulfur may be substituted as a spray. Repeat the treatment in a week to get any young hatching from the eggs.
2. A driving, forceful spray from a garden hose, applied to the undersides of leaves two or three times, at five-day intervals, is a cheap, effective treatment where the water and hose are available.
11. The European Corn Borer:
Although corn-borer injury is usually associated with sweet corn, a very wide range of plants suffers from this pernicious. Nearly all succulent large-stemmed plants and their fruit, including such vegetables as potatoes, tomatoes, peppers, and eggplants, may be severely injured. Even the new shoots of raspberries and the mature fruit of apples and peaches may be attacked under conditions of heavy infestation. The corn- borer moths are night-flying and lay their white, scaly eggs in masses, mainly on the undersides of foliage.
On corn, the egg masses are most common on the oldest, smallest leaves near the ground. There are two generations of corn borers a year in the vicinity of New York City and farther south, while in more northern areas a one-generation strain predominates.
Control:
1. Because of its habit of boring within stems or fruits, control of the borer is very difficult. Since the full- grown borer larvae overwinter in large-stemmed weeds, vegetables, and corn, including the stubble, burning, or better yet plowing under, such plants in the fall or early spring is effective in reducing their population in an area.
2. In addition, their control consists of spraying or dusting the plants to be protected, at intervals of five days for four or five applications, beginning when the first-laid eggs are about to hatch. Within about one hundred miles of New York City, hatching usually begins for the first generation in early June and for the second in early August. Examine eggs daily at these times to determine the exact time to begin applications. A choice of formulas is given, as some materials are not available at the present time.
Sprays:
1. Derris, cube or timbo powder (4% rotenone content) – 3 ½ tbsp.
Spreader-sticker, mfr.’s directions Water – 1 gal.
2. Black Leaf 155 – 2 tbsp.
Spreader-sticker, mfr.’s directions
Water – 1 gal.
Dusts:
1. Dual-fixed nicotine dust
2. One per cent rotenone dust
3. Black Leaf 155 dust, containing at least 4% nicotine
In the case of sweet corn, which is about the only plant practical to protect, the sprays or dusts should be applied to the leaf axils and into the whorls to kill the newly hatched larvae as they attempt to bore into the plant.
Corn planted between May 20 and June 15 in normal years, so that it matures during the first three weeks in August, is fairly free of corn borers in the two-generation areas.
12. Leafhoppers:
Leafhoppers are important pests of many different plants, retarding growth and reducing vigor when they are abundant. They are tiny, slender, vari-colored insects that hop or fly short distances when disturbed. These pests are found mainly on the undersides of foliage, where their sucking produces a whitish stippling on the upper leaf surfaces.
Some species are, in addition, carriers of plant diseases. Some of the more common leafhoppers found in gardens are the white apple leafhopper, the grape leafhopper, and the potato or bean leafhopper. There are usually two broods a year, with the second one generally causing most of the damage.
Control:
1. Control is generally directed against the nymphs, although adults are also killed when hit. When these pests are observed to be abundant, they may be held in check by spraying the undersides of the foliage, twice at two-week intervals, with a pyrethrum spray or dust, or with this formula –
Nicotine sulfate –1 ½ tsp.
Soap powder – 3 tbsp.
Water – 1 gal.
2. On potatoes, the regular Bordeaux sprays for diseases act as effective repellents for the potato leafhopper.
Virus Diseases of Vegetables and Fruits:
Many vegetables and some fruits are frequently affected with diseases caused by viruses. The vegetables most susceptible to virus diseases are beans, peas, spinach, lettuce, cucumbers, tomatoes, potatoes, and peppers; the fruits most susceptible to them are peaches, raspberries, blackberries, and strawberries.
The symptoms produced by virus diseases in plants may be divided into three groups:
(1) Either a general yellowing or a mottling of the foliage with alternate patches of light green, yellow, and dark green;
(2) A destruction of the tissue, causing dead spots, streaks, or strips;
(3) A stunting and distortion of growth involving parts of the plant or the whole plant. A single virus, during different stages in its attack, may produce symptoms mentioned in all three groups.
The viruses may be transmitted from diseased to healthy plants by one or more means:
(1) Budding or grafting from diseased stock;
(2) Seed from infected plants;
(3) Contact- by touching diseased and healthy plants;
(4) Pollen from diseased plants;
(5) Insects feeding on diseased and healthy plants. All viruses may be transmitted by the first method, but the specific virus disease determines by what other method or methods it may be transmitted.
Control:
Control of virus diseases is dependent largely on their method of transmission.
1. Never graft or bud from diseased stock.
2. Purchase pea, bean, and lettuce seed and plant stock that is free from virus.
3. Destroy all susceptible wild plants and weeds in the neighborhood.
4. Control insects that may transmit the virus diseases.
5. Pull out and destroy any plants showing virus-disease symptoms.