Nematode Diseases of Plants, Ohioline

Ohioline

Ohio State University Extension

Nematode Diseases of Plants

This is the eighth fact sheet in a series of ten designed to provide an overview of key concepts in plant pathology. Plant pathology is the study of plant disease including the reasons why plants get sick and how to control or manage healthy plants.

A number of genera and species of nematodes are highly damaging to a great range of hosts, including foliage plants, agronomic and vegetable crops, fruit and nut trees, turfgrass, and forest trees. Some of the most damaging nematodes are: Root knot (Meloidogyne spp.); Cyst (Heterodera and Globodera spp.); Root lesion (Pratylenchus spp.); Spiral (Helicotylenchus spp.); Burrowing (Radopholus similis); Bulb and stem (Ditylenchus dipsaci); Reniform (Rotylenchulus reniformis); Dagger (Xiphinema spp.); Bud and leaf (Aphelenchoides spp.); and Pine Wilt Disease (Bursaphelenchus xylophilus).

Morphology

Figure 1. Adult root-knot nematode. Photo courtesy G. S. Abawi, © The American Phytopathological Society.

Nematodes are simple, multi-cellular animals—typically containing 1,000 cells or less. They are worm-like in appearance, but are taxonomically distinct from earthworms, wireworms or flatworms. They are bilaterally symmetrical, soft-bodied (no skeleton), non-segmented round worms. Most nematode species that attack plants are microscopic. The basic body plan of a nematode is a “tube within a tube.” Nematodes feed on other microorganisms and plants like bacteriovores, fungivores, omnivores, predators, and plant parasites. Some, however, are serious human, animal and plant pathogens. Those that attack animals or humans do not attack plants and vice versa. Heartworm in dogs and cats is an example of nematode diseases in animals and people.

Plant parasitic nematodes may attack the roots, stem, foliage and flowers of plants. All plant parasitic nematodes have piercing mouthparts called stylets. The presence of a stylet is the key diagnostic sign differentiating plant parasitic nematodes from all other types of nematodes. The bacterial-feeding nematode, Caenorhabditis elegans, is one of the best-understood animals on earth. It was the first animal to have its entire genome completely sequenced. The study of C. elegans has led to many new insights into animal development, neurobiology and behavior.

Signs and Symptoms

Typical root symptoms indicating nematode attack are root knots or galls, root lesions, excessive root branching, injured root tips and stunted root systems. Symptoms on the above-ground plant parts indicating root infection are a slow decline of the entire plant, wilting even with ample soil moisture, foliage yellowing and fewer and smaller leaves. These are, in fact, the symptoms that would appear in plants deprived of a properly functioning root system. Bulb and stem nematodes produce stem swellings and shortened internodes. Bud and leaf nematodes distort and kill bud and leaf tissue. In some cases, such as with SCN, yield loss may take place with no visible symptoms.

Dissemination

Parasitic nematodes are readily spread by any physical means that can move soil particles about—equipment, tools, shoes, birds, insects, dust, wind and water. In addition, the movement of nematode-infested plants or plant parts will spread the parasites.

Figure 2. Adult lesion nematode. Photo courtesy Union Carbide, © The American Phytopathological Society.

Control

Various methods are available to reduce crop losses from nematodes:

1. Genetic Host Resistance
  • Plant resistant species and cultivars. For example, in an area with soil heavily infested with the root-knot nematode, plant apricots, cherries, apples, pears or plums, which are resistant, rather than peaches or nectarines, which are highly susceptible. (A root-knot nematode-resistant peach rootstock called ‘Nemaguard’ developed by USDA plant breeders is available, thus permitting peach production even on infested soils.) Certain vegetable crops—sweet corn, asparagus, and cabbage—are resistant to root-knot nematodes whereas radishes are susceptible. Resistant ornamentals include the African marigold, azalea, camellia and oleander. In Long Island, New York, where the golden nematode is a serious problem for potato production, resistant cultivars are available. Similarly, soybean varieties resistant to soybean cyst nematode (Heterodera glycines) are also available.
2. Cultural Practices
  • Use only nematode-free nursery stock for planting. In most countries, government nursery inspectors will condemn and destroy any nursery stock showing evidence of nematode infestation.
  • In nursery operations, use benches raised off the ground and pot plants only into pasteurized soil mixes. Keep containers, bins, benches and flats clean. Fumigate outdoor growing fields where nursery stock will be grown.
  • Rotate crops to control certain nematodes. Rotation is useful for types that have a narrow host range, such as sugar beets attacked by the sugar beet cyst nematode. Where the crop value is too low to justify large-scale soil fumigation, crop rotation is the only practical method of nematode control.
  • Use cover crops that reduce nematode damage. Cover crops can improve soil structure and fertility, decrease soil erosion, be used as animal feed, and suppress weeds, insects and pathogens. Examples of cover crops that have been shown to suppress nematodes include cowpea, rapeseed, velvet bean and sudangrass.
Figure 3. Aerial view of damage due to soybean cyst nematode. Photo courtesy G. L. Tylka, © The American Phytopathological Society.

3. Chemical Applications

  • Treat the soil area with a fumigant before planting. Soil mixes for container-grown plants can either be treated with a fumigant or steam-pasteurized at 82 degrees C (180 degrees F) for about 30 minutes. This method is too expensive for field crops other than commercial strawberry fields. The impending loss of methyl bromide may seriously affect the crops where it is used.
  • Use nematicides in certain cases. All nematicides are poisonous and must be used carefully, following the directions on the containers exactly. Most such materials will injure or kill plants if applied too close to their root zones. As the number of commercially available nematicides decreases, greater emphasis has been placed on the development of alternative IPM practices.
4. Biological Control

• Although not widely available, scientists have explored the use of antagonistic fungi like Arthrobotrys dactyloides to trap and parasitize plant pathogenic nematodes. Pasteuria penetrans, a bacterial parasite, can also be used as biological control.

Figure 4. White female soybean cyst nematodes on root surface. Photo courtesy R. D. Riggs, © The American Phytopathological Society.
5. Government Regulatory Measures

• Avoid importing soil (or plants with soil on their roots) from areas that could be loaded with a dangerous nematode species new to the area. United States plant importation regulations forbid the introduction of plants with soil on their roots from other countries.

Introduction to Plant Disease Series

  • Plants Get Sick Too! An Introduction to Plant Diseases
  • Diagnosing Sick Plants
  • Questions on Plant Diagnosis
  • Keeping Plants Healthy: An Overview of Integrated Plant Health Management
  • Viral Diseases of Plants
  • Bacterial Diseases of Plants
  • Fungal and Fungal-like Diseases of Plants
  • Nematode Diseases of Plants
  • Parasitic Higher Plants
  • Sanitation and Phytosanitation (SPS): The Importance of SPS in Global Movement of Plant Materials

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Fungus Gnats on Plants

Protect your seedlings from this problematic pest

gailhampshire / Flickr / CC By 2.0

Fungus gnats are tiny mosquito-like insects, about one-eighth of an inch in length. They can be hard to see while flying, but you will probably notice them when they are darting about newly sprouted seedlings.

Being so small, they can enter your home or greenhouse through the slightest of openings. More often they come in as eggs, either in the soil of plants that have been outside for the summer or in damp bags of potting soil. It only takes a couple of fungus gnat to cause a major problem because they reproduce so quickly.

Fungus Gnat Damage

Adult fungus gnats are mostly an annoyance, but the larvae can do damage to young plants and seedlings by feeding on the new, tender roots. They may feed on the callused over-area of cuttings, delaying the development of new roots.

By feeding on the roots of young plants, undue stress is put on them as they try to establish themselves. Additionally, the damaged roots provide an entryway for disease pathogens. The first symptom of damage is usually wilting, followed by a general decline of the plant. If you notice very young seedlings collapsing or looking like they have simply rotted in place, it is probably the result of fungus gnat damage.

The Lifecycle of Fungus Gnats

To control the population of fungus gnats, it helps to know their lifecycle and when they are actively feeding. Fungus gnat eggs are laid in cracks on the soil surface. They hatch into larvae within six days and begin feeding on plant roots. After feeding for about two weeks, they pupate in the soil and emerge in less than a week as adults to begin the cycle all over again.

Fungus gnats give birth to mostly females, which enables the population to increase rapidly. One female can lay between 100 to 300 eggs.

How to Control Fungus Gnats

The best way to control fungus gnats is to employ all three of the following methods:

Monitoring and Killing Adult Gnats

Get an idea of the adult population of fungus gnats is by using yellow sticky cards. These small, yellow-colored cards have an adhesive on both sides. You can find them at most garden centers. Place the cards standing up on the soil surface. The adult fungus gnats are attracted to the color yellow. They will fly towards the cards and get trapped there by the adhesive. It is not a pretty sight, but it will give you a good idea of the size of the population while killing them in the process.

Deterrence

If you are working in a greenhouse, do a thorough cleaning before you begin new seedlings. Soil and weeds on the floor are attractive to fungus gnats.

In addition to feeding on plant roots, fungus gnat larvae will consume organic material in the soil. Avoid potting mixes containing fresh compost, which seems to be attractive to them because of its high microbial activity.

Fungus gnats are more attracted to soil that stays moist, so use a well-draining potting mix and allow it to thoroughly dry out before watering again. (Don’t leave the soil dry for more than a day, or you could kill your seedlings with drought.) Be extra cautious with potting mix stored outdoors. It is often wet and very likely will contain fungus gnat larvae.

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Biological Controls for Larva

Placing a slice of potato on the soil surface sometimes attracts the feeding larva. The potato slices can be used to collect and dispose of larva and to gauge when the larva are actively feeding, for the timing of pesticide applications. Make sure the potato slices do not dry out.

A form of Bacillus thuringiensis (var. israelensis), has been shown to be effective against the larva when they are at the feeding stage. It is sold under the trade name of Gnatrol. The bacteria must be eaten by the larva. Gnatrol only stays active for two days and will require repeat applications. Follow the package instructions.

There is also a type of nematode, Steinernema feltiae, that can be used to drench the soil. These tiny worm-like creatures will actually enter the larvae. There they release a bacterium that is lethal to the larvae.

Since the last two controls mentioned are living organisms, you probably won’t find them sitting on a shelf in the nursery. However, they are available from many catalogs, through mail order, and some nurseries will stock them during seed starting season.

Over the counter gnat or «flying insect» sprays are effective against adult fungus gnats, particularly those containing pyrethrins. Again, multiple applications may be necessary.

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Methods of dealing with potato ladybug or epilya

Every summer, all summer residents and those who have their own vegetable garden, face the same problem: pest invasiondestroying and damaging cultivated plants.

One such pest of vegetable crops is the potato bug bug, or otherwise, epilahny.

Let’s try to figure out what a potato bug is, where it can be found and how to deal with it?

To fight with the beetle was effectiveIt is important to know about some stages of its development, periods of greatest activity and plants that are most vulnerable to its attack.

Appearance

It is a 5-7 mm long bug, resembling in appearance ordinary ladybug, with one difference — there are as many as 28 points on the wings.

The color itself is also not so bright — brown-red or red. An interesting feature is lightweight. whitish bloomwhich is in fact the smallest hairs.

Photos of epilahna and its larvae:

Development cycle

Potato cows are developing at a fast pace: one female can postpone from 250 to 520 eggs. Laying 10-20 pieces can be found on the underside of the leaves of potatoes or in fallen leaves.

The size of the eggs do not exceed 1 mm and have a pale yellow color.

After 3-7 days, the larvae come to light, for 20 days they pupate and remain in this state for 9 days. It is worth noting that despite the rapid development, 28-point ladybug multiplies once a year — from May to June.

Background: epilakhn larvae have a very unusual look, resembling caterpillar yellowish-green color, the whole body of which is covered with black setae (in the photo on the right). They are very soft and completely non-poisonous, they are needed more for movement.

Lifestyle

Beetles are constantly changing their habitat, moving to different plants, and with the onset of cold weather, hiding in shelters. They can winter under dry leaves, plant debris and weeds, and sometimes burrow into the soil.

Eats a 28-point potato bug not only with potato shoots, but also with leaves of other solanaceous, for example, tomatoes. It is also known that beetles like to eat cucumbers, watermelon, pumpkin, soybeans, sunflower and corn.

The greatest harm to the crop a potato ladybug inflicts during the development of the larvae and before the departure of young beetles for wintering.

Tuberization occurs at this stage, which entails not only damage already ripe tubers, but also the destruction of more emerging, which significantly reduces the yield.

Increased activity is associated with the desire of beetles to gain strength and stock up on nutrients before winter. Beetles and larvae eat only the soft part of the leaf, leaving the veins.

In general, applied damage is slightly less than from the Colorado potato beetle.

In addition to eating leaf mass, epilachny carry viruses that are harmless to them, but dangerous for plants.

Methods and means of struggle in the garden

How to deal with 28 point ladybug in the garden? Consider the most effective methods of dealing with it:

  1. Most simple measure — place solanaceous crops as far as possible and more isolated from each other, so as not to attract too many beetles and not to create favorable conditions for reproduction (females lay eggs simultaneously in several places, and since they choose solanaceous ones for this, such a measure will reduce the area distribution).
  2. Place cultures of solanaceae best on well cleaned areaswhere there are no dry leaves and other suitable covers.
  3. Weeds should be completely excluded. If it was not possible to eradicate them before the breeding season (May-June), then the epilakhns can lay eggs on weeds.
  4. Can hold high hilling plants. Beetles and larvae that fall from the plant will be under a layer of soil and die.
  5. Well, and, of course, insecticides.

Chemical treatment, in the case of increased risk of harm, can bring its results, but do not forget harmwhich they cause to human health.

Thus, if you have your own vegetable garden or a few hundred square meters in a country house where you like to grow potatoes, cucumbers, tomatoes or sunflowers, be ready to the summer invasion of small voracious bugs that can, if not destroy, then damage the plants you grow.

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GARDEN + GARDENING + GARDENING TIPS & ADVICE

Strawberries — Diseases, Pests and Problems

Basic Information

Problem: Frost Injury
Affected Area: Weather injury that affects the flowers, pistils,

Description: Frost injury kills the pistils causing the flowers to turn black. In severe conditions, the flower may die or a few pistils may survive and the flower may produce deformed fruit.

Control: Overhead irrigation and plastic tarps can be used to prevent frost damage.

Problem: Winter Injury
Affected Area: Weather injury that affects the entire plant.

Description: Winter injury results when ice crystals are formed at the base of the plant. The plant will lose its vigor, become more susceptible to diseases, and turn brown at the base by the crown.

Control: Winter injury can be prevented by insulating the plants with mulches and selecting a variety of plant that are good for the specific climatic region.

Problem: Lightning Damage
Affected Area: Weather injury that affects the entire plant.

Description: Lightning damage in strawberry fields can be easily detected by the circular areas that are dead or dying and the outer areas of plants that have darkened leaves.

Control: Lightning damage cannot be controlled or prevented.

Problem: Hail Injury
Affected Area: Weather injury that affects the entire plant.

Description: Hail injury is very detrimental during the flowering season and while the fruit is maturing. The fruit can be knocked of the plant or bruised and scarred with brown spots and the leaves many times are battered and scarred.

Control: Hail injury cannot be controlled or prevented

Problem: Nitrogen
Affected Area: Nutrient problem that affects the entire plant

Description: Nitrogen is needed in large amounts for strawberry plants. The lack on the required amount of nitrogen in strawberry plants results in smaller fruits, fewer runner, and the older leaves turn orange or red, while the younger ones are shorter and are a pale green color. Excess nitrogen will cause the quality of fruit to decrease and other diseases to increase.

Control: Soil tests can be taken to see if there is a proper amount of available nitrogen in the soil, but the availability often fluctuates and more can be added as needed.

Problem: Potassium
Affected Area: Nutrient problem that affects the entire plant

Description: Symptoms of potassium deficiency are rough edges of the older leaves, dark leaflets, wilted leaves in high temperatures and softened fruit as well.

Control: Soil tests can be taken to see if the potassium is at the proper level and more can be added as needed. Potassium bicarbonate is an effective foliar spray that can be added to prevent other diseases and give the needed potassium to the plant.

Problem: Boron
Affected Area: Nutrient deficiency and toxicity that affects the

Description: Symptoms of boron deficiency are slow root growth, deformed berries, and lop sided leaves. Symptoms of toxicity are hard, yellow berries, and rough leaf edges.

Control: Boron can be controlled by taking soil samples and keeping it in a range that neither toxic nor deficient to the plant.

Problem: Problems Caused by Weeds and Herbicides
Affected Area: Weed and herbicide injury affects the entire plant

Description: Weeds become problems in strawberries creating competition with the desired plants and negative aesthetic appeal, which then requires time and money to control. Herbicides can damage the leaves, roots, and the entire plant often killing it if not used properly.

Control: Weeds can be eliminated using cultural, biological, mechanical, and chemical controls. The most common are the mechanical and chemical controls such as cultivation, hand weeding, selective herbicides, and pre-plant and post emergence herbicides. The timing is very important with herbicides as well as choosing the proper herbicide and using the correct rate.

Problem: Angular leaf spot
Affected Area: Disease of the leaf caused by bacteria

Description: Angular leaf spot generally first appears as water soaked spots on the leaves. The leaf tends to turn translucent, later reddish brown spots appear, and the plant dies.

Control: The best control measures are to avoid overhead irrigation when possible and use clean planting stock. Other control measures are available such as antibiotics and copper-containing pesticides, but can cause phytotoxicity.

Problem: Powdery Mildew
Affected Area: Disease of the leaf caused by fungi

Description: White powdery spots appear on the undersides of the leaves. The white spots become bigger and eventually cover the whole underside of the leaf and the leaf itself begins to roll up. Purple/reddish blotches may begin to form on the upper and lower leaves. Fruit may become deformed and the plants may not produce well.

Control: Some controls may include using protective fungicides, resistant plants, and avoiding overhead irrigation if possible.

Problem: Phomopsis Leaf Blight
Affected Area:

Description: The symptoms first include five or six circular purplish spots and later combine along the veins to make large V-shaped areas that turn dark brown and black and die off.

Control: Some control measures that can be taken are removing older and infected leaves to help the foliar fungicide to be more effective.

Problem: Leaf Spot
Affected Area:

Description: Leaf spot is one of the most common diseases in strawberries. It is also known as Mycosphaerella leaf spot, Ramularia leaf spot, ?rust,? bird?s-eye spot, ?gray spotness,? and white spot. Leaf spot usually occurs in the springtime with wet cool weather and the symptoms generally include small lesions or spots, which become larger and start with a purplish color and change to red, brown, gray and eventually white.

Control: Control measures include selecting certain varieties that are more resistant than others. Common fungicide sprays may be used to reduce the symptoms and prevent disease buildup.

Problem: Rhizoctonia Leaf Blight (Web Blight)
Affected Area:

Description: This disease attacks older leaves and leaves a grayish or black color. Younger leaves become deformed and curled. High soil moisture levels and relative humidity are the main causes of this disease.

Control: Some control measures may in include avoiding sprinkler irrigation and using alternative irrigation methods.

Problem: Botrytis Fruit Rot (Gray Mold and Blossom Blight)
Affected Area:

Description: Botrytis fruit rot is generally noticed on ripening or ripened fruit, but can also occur on blossoms or premature fruit. This disease tends to develop on cool wet climates. Affected blossoms turn brown and die off. Symptoms of rotting occur on the fruit with browning of the tissue that spreads over the entire fruit and can cause the fruit to die before maturity. The rotted fruit will eventually become hard, tough, and dry. Some varieties are partially resistant to the this disease.

Control: Treating transplants with fungicides, spraying fungicides during the flowering period, and reducing injury during and after harvest are some of the best control measures for this disease.

Problem: Anthracnose Fruit Rot (Black Spot)
Affected Area:

Description: Anthracnose fruit rot occurs during harvest time with rainy warm conditions. Some of the symptoms of fruit rot start with water soaked spots forming on the growing fruit. The spots start with a light brown color and change to dark brown or black. Under humid conditions pick and orange spots may cover the existing spots. This disease also affects flowers. Open flowers quickly die and dry out, while flower buds that are just emerging have their petals burnt on the tips. The resulting fruit is usually small and hard with some deformities.

Control: Some controls may be implemented by establishing new plantings with anthracnose-free plants, drip irrigation, and using straw mulch between rows.

Problem: Leather rot
Affected Area: Disease of the fruit caused by fungi

Description: Symptoms of leather rot on premature fruit show brown spots on the fruit and then spreads to eventually cover the entire fruit and give it a leathery rough look. Infection of mature fruit may cause brown or purple colors to appear, and the fruit begins to decay giving it a bad odor and taste.

Control: Cultural controls for leather rot can include proper site selection for planting and reducing standing water or excess water in the field. Fungicides may also be used to reduce and rid an area of leather rot.

Problem: Phomopsis Soft Rot
Affected Area: Disease of the fruit caused by fungi

Description: Symptoms of phomopsis soft rot generally occur on mature ripening fruit. Brown spots occur on the fruit with a light brown color on the edges and a darker brown toward the center and it being crusty.

Control: No specific controls have been found for this disease.

Problem: Mucor Fruit Rot
Affected Area: Disease of the fruit caused by fungi

Description: Enzymes are produced from the fungus that attacks the mature fruit and causes the fruit tissue to deteriorate.

Control: The best way to control the fruit rot is to remove any ripened fruit and use proper fungicides and keep all harvesting and handling areas sanitary.

Problem: Red Stele Root Rot
Affected Area: Disease of the root and crown caused by fungi

Description: Depending on the severity of the infected plant red stele rot can show different symptoms. A severely infected plant will show signs that are visible above ground which include stunted growth with little or no fruit and wilting in hot weather. The younger leaves may turn bluish green and the older leaves may become red, yellow, or orange. Less infected plants will not show many above ground symptoms the main root will start to rot and red discoloration will appear on the root.

Control: To control red stele root rot it is best to select varieties of plants that have been inspected and certified disease free. Avoid planting in low wet spots and in soil with poor drainage. Some varieties of plants are resistant to red stele rot, but can become susceptible to the disease after time. Some fungicides have proven to work to prevent this disease.

Problem: Rhizoctonia solani Root Rot
Affected Area: Disease of the root and crown caused by fungi

Description: Symptoms of this disease include collapsing of the plant in the early part of the fruiting period, purple coloring, and curling up of the underside of the leaves. The petiole, or the part connecting the leaf to the stem, turns brown and the crowns are killed along with some of the smaller roots.

Control: Some soil fumigants have proven to be effective to rid an area of this disease.

Problem: Strawberry Mottle Virus
Affected Area: Aphid-borne virus affects the entire plant

Description: Symptoms of this virus include mottle and slight distortion of the leaves, along with stunted growth of the plant.

Control: Several control methods for this virus include the use of certified virus-free plants, aphid control, and avoid planting close to infected areas.

Problem: Tomato Ring Spot Nepovirus
Affected Area: Nepovirus that affects the entire plant

Description: Symptoms of this virus may include stunted growth, reduction in the number of runners, and the eventual death of the leaves and plant.

Control: Certified virus-free plants can be used to reduce the virus and stop it from spreading. Also soil fumigants can be used to rid an area of nematodes, which help spread and maintain the virus in the soil.

Problem: Strawberry Pallidosis
Affected Area: leaves

Description: Symptoms of this disease include leaflet distortion and small growth of the plants.

Control: Using disease free plants is the most effective way of eliminating this disease.

Problem: Strawberry Aster Yellows
Affected Area: entire plant

Description: Symptoms of this disease include stunted growth and cupping of the young leaves and deformities of the fruits.

Control: Heat treatment can help control this disease.

Problem: Phytoplasma Yellows
Affected Area: entire plant

Description: Symptoms of this disease include purple and bronze colored leaves, stunted growth and whitening of the leaves. The plant will usually die shortly after the symptoms show up.

Control: No specific controls have been found for this disease.

Problem: Summer Dwarf
Affected Area: leaves and fruit

Description: Symptoms of this disease include cupping and stunted growth of younger leaves while older leaves remain unaffected. The fruit may become deformed in the maturing process.

Control: Controls for this specific disease include planting nematode-free plants, using heat therapy, and finding the affected plants and talking them out and destroying them.

Problem: Root-Lesion Nematode
Affected Area: root

Description: Symptoms of root-lesion nematodes include brown spots and/or complete blackening of the roots.

Control: Soil fumigation is the most effective control measure

Problem: Sting Nematode
Affected Area: entire plant.

Description: Symptoms of the sting nematode include stunted growth, course roots with blunt tips, black spots on the roots, and few fine roots.

Control: Some common controls of sting nematode include fumigants, nonfumigant nematicides, and using different types of plants in the planting areas.

Problem: Dagger and Needle Nematode
Affected Area: roots.

Description: Symptoms of dagger and needle nematode include enlarged growths at the ends of the roots, stunted plant growth, and reduced runner production.

Control: Most fumigants that are used for other nematode related disease can be used to treat dagger and needle nematode.

Problem: Strawberry Aphids
Affected Area: Can cause various diseases

Description: Strawberry aphids can be found in any type of region where strawberries are grown. The aphids that attack strawberries are soft-bodied insects. Pale green aphids are the wingless form and are females and the light green ones are the winged aphids. They are most numerous in the spring and fall because of the hot dry climate during the summer months. They also can produce several generations through the growing season.

Control: Using the proper insecticides in the proper conditions and environments can control strawberry aphids.

Problem: Strawberry Root Aphid
Affected Area: Affects the entire plant

Description: Strawberry root aphids are a soft-bodied insect about 2 mm long. The aphid can vary in color from a pale green to a bluish black. Strawberry root aphids can be distinguished from strawberry aphids by their bluish color and short egg shaped bodies. These aphids usually attack and eat the leaves and stems of the plant and then are carried or transferred down to the roots by ants allowing the aphids to suck the sap from the tissues of the root. The plant will then turn very pale and look unhealthy, producing small fruit.

Control: Using aphidcides for the aphids above ground and tilling the soil deep before planting to control the ants that help the aphids survive below ground are effective controls for the strawberry root aphid.

Problem: Cyclamen Mite
Affected Area: Affects the above ground portion of the plant

Description: The cyclamen mite is very small and difficult to see with the naked eye. The cyclamen mite feeds on leaves near the crown of the plant until the leaves become stunted, crinkled, and deformed. When the leaves become brown and dry and the mites move to the flowers causing them to die. The fruit produced from the infested plants are cracked, distorted, bronzed, and the seeds stick out of the flesh of the fruit.

Control: Infected plants can be removed and destroyed when found preventing the spread on the mite. No other specific control has been found to prevent the cyclamen mite.

Problem: Spider Mites
Affected Area: Insect that affects the above ground portion of th

Description: Spider mites begin to attack the undersides of young strawberry leaves in the early spring. The top of the leaves may produce small, yellow spots after they are infected. The yellow spots do not always appear late in the season, but the browning and drying out of the lower surface of the infected leaves are the most prevalent symptoms.

Control: Spider mites can be controlled by naturally by predators that live in the soil and by wet, cool weather conditions. Pesticides are not very effective and can cause negative effects on native predator mites.

Problem: Lygus Bugs
Affected Area: Insect that effects the fruit of the plant

Description: Lygus bugs are about 6-6.5 mm long and oval and are a greenish or brownish with reddish brown marking of the wings. Some lygus bugs have a small yellow triangle on the back. The bugs attack the seeds of the fruit by puncturing them stopping the development of the fruit in the infected area.

Control: Insecticides and weed control around the plants can be used to control lygus bugs.

Problem: Strawberry Bud Weevil
Affected Area: Insect that affects the buds of the plant

Description: Strawberry bud weevils are a dark reddish color and about 2.5 mm long. The weevils feed on pollen from the blossom buds that they get through puncturing the buds. The female then leaves an egg inside the bud leaving it to hatch.

Control: Rotating strawberry patches at least every three years and tilling the areas after the growing season can help reduce the infestation of the strawberry bud weevil.

Problem: Spittlebugs
Affected Area: Insect that affects the above ground portion of th

Description: Spittlebugs bury themselves in a saliva-like mass and the secretion that they give off inhibits strawberry pickers to get the fruit. The spittlebugs feed on the plants juices at the base of the plant and move up to the more tender parts of the plant.

Control: Insecticides can be used to effectively spittlebugs.

Problem: Chewing Insects
Affected Area: Insect that affects the entire plant.

Description: Root weevils are shiny black or brown and measure to 5-6 mm in length. These weevils tend to eat notches out of the leaves and eventually move down to the crowns and roots of the plant. The damage to the crowns and roots is the more serious damage to the plant causing stunted growth, and eventually killing the entire plant.

Control: A few insecticides may be used to control root weevils.

Problem: Flower Thrips
Affected Area: Insect that affects the flowers and fruit of the p

Description: Flower thrips are very short yellow insects that are hard to detect. Up to ten thirps can attack one flower of a strawberry plant before any type of insecticide is needed. Thirps generally attack the flower and move to the fruit causing bronzing and hardness of the fruit.

Control: Control measures may include the application of one of various insecticides or choosing a variety that is less susceptible to flower thrips.

Problem: White Grubs
Affected Area: Minor insect

Description: Control measures may include preplant soil treatments with soil fumigants and insecticides.

Control: Pest

Problem: Leaf Rollers
Affected Area: Minor Insect

Description: Many natural parasites help control the leaf rollers to a low population.

Control: Pest

Problem: Strawberry Sap Beetle
Affected Area: Insect that attacks the fruit of the plant.

Description: Strawberry sap beetles are small and very thing with pale spots their bodies. These insects attack the fruit as it begins to ripen creating holes in the fruit and reproducing inside the fruit. It is difficult to detect because the insects make their holes at the bottom of the fruit and are rarely seen.

Control: Control of strawberry sap beetles is difficult to accomplish because of the restrictions of insecticide use just before harvest. But picking and destroying rotten and infested fruits will decrease the damage for the next crop and lower the population.

Problem: Slugs and Snails
Affected Area: Leaf

Description: Large portions of young plants missing.

Control: Slugs and snails are very susceptible to desiccation (drying) and require a moist, shady place to live. Cultural practices which promote a sunny, dry environment will discourage them. Avoid too-frequent waterings allowing soil surface to dry out between irrigations. Keep garden free of debris, boards, bricks, and stones where they hide. Hand picking these pests is very effective. Create ?traps? for hand picking by laying boards in the garden. Slugs and snails will congregate under them. Lift the boards each morning and collect the slugs and snails. Dispose of them completely as they will crawl back if tossed out of the garden and eggs inside dead pests can still hatch to produce more of these pests. Slug and snail bait containing metaldehyde can be placed near food plants as long as they do not contact edible portions of the crop. Most effective when moistened, but not water logged. Snail bait attracts slugs and snails from several feet away so bait stations are effective. Stations help protect birds, pets and other non-target animals which are also attracted to the bait. Place small piles of bit under a slightly propped up board or use container such as a cottage cheese or yogurt carton. Bury carton to the mouth of the container. Place small amount of commercial bait inside and moisten with apple juice, orange juice or water. Cut hole in lid to allow access and place lid on container. Containers may also hold beer or yeast water to attract slugs and snails in where they drown. Place bait stations wherever slugs and snails are active or around perimeter of garden.

Problem: Strawberry Root Weevil
Affected Area: Root

Description: Adults are 3/8 inch, grayish-black or brown/black beetles with short snouts, and elbowed antennae. Strawberry root weevil wings are fused and the insects do not fly. True to its name, the strawberry root weevil is most attracted to strawberries and can cause severe damage to them. Adults emerge from the soil during the night and feed on leaves of plants. Leaf damage is largely cosmetic. Beetle larvae live underground and feed on the roots. The larvae are plump, up to 1/2 inch long and lightly curved with brown heads and no legs. They cause the real damage as their root feeding can cause the plants to grow slowly, wilt, collapse, and die.

Control: Destroying old beds of strawberries can kill developing larvae. This is best done after the eggs are laid. Move new strawberry beds, using new plants, to other locations as far as possible away from the old beds. Keep the area cleaned up to avoid giving the adults a shelter. If the problem is serious, treat food plants with *Diazinon in midsummer and again one month later, or use a commercial bait such as *Morgro Pest pellets * Pesticide use and recommendations for various areas are constantly changing. Check with your County agent for current recommendations.

Problem: Leaf roller
Affected Area: Leaf

Description: Caterpillars which roll up or tie up leaves with their silk

Control: * Malathion or *Dipel * Pesticide use and recommendations for various areas are constantly changing. Check with your County agent for current recommendations.

Problem: Birds
Affected Area: Leaf

Description: Birds are fond of strawberries and consistently damage fruit flying in to pluck it or peck at it.

Control: Bird netting over plants.

Problem: Earwigs
Affected Area: Leaf

Description: Reddish-brown elongated insects up to 1″ long with pincers up to 1/4 inch long. Adult have two pairs of small wings but rarely fly. Earwigs are nocturnal hiding in convenient, dark cook place during the day and emerging at night. They feed primarily on decaying materilas, but also attack fruits, blossoms and vegetables

Control: Yard sanitation. Remove surface debris wihch provides shelter. Spray with *sevin (do not spray blooming plants) or *malathion. * Pesticide use and recommendations for various areas are constantly changing. Check with your County agent for current recommendations.

Problem: Grasshoppers
Affected Area: Leaf

Description: Long jumping insects which may develop wings on adulthood. Have a voracious appetite for leaves, fruits and vegetables. Often abound in weeded areas moving into the garden to feed. Lay eggs which winter over and hatch out in the spring in undisturbed soil. Newly hatched grasshoppers are about 1/4 to 3/8 inch long. They do not develop wings until they have passed through four to five immature stages.

Control: Cultural controls are important to limit grasshoppers. The insects are most abundant in undisturbed areas such as fields of dry grass, along fences, in ornamentals, and in weed patches. Control weeds by tilling or mowing and spray in these areas to reduce grasshopper infestations. Tilling or otherwise working the soil interrupts the grasshopper’s life cycle. This is especially effective right after harvest in the fall. It stirs up the eggs, moving them deeper into the soil where they will not hatch or brings them to the surface where birds eat them or frost, sun and wind destroy them. Tilling is still of value in the spring. Grasshoppers seek undisturbed soil to lay their eggs, so tilled soil is unattractive to egg-laying. Till unused strips of ground surrounding the landscape to keep the insects at bay. Chemical controls are most effective on young insects. They become less susceptible as they pass through each stage until they develop adult wings. With wings they develop mobility and become more difficult to treat. Concentrate sprays in shady areas, weedy areas, and bushes where hoppers are concentrated. *Diazinon can be used on most edible crops. It is most effective on newly hatched or small grasshoppers. It’s residual action lasts one to two weeks. *Malathion destroys insects quickly but its residual effect lasts just a few days. It is safe to use on food crops within a few days of harvest. *Sevin, which lasts longer than malathion, is very effective on grasshoppers, but particularly hazardous to bees. The product can be carried into the hive where it spreads the damage among these beneficial insects. Never spray sevin while plants are in bloom. * Pesticide use and recommendations for various areas are constantly changing. Check with your County agent for current recommendations.

Problem: Powdery Mildew
Affected Area: Leaf

Description: White powdery substance on leaves.

Control: Use surface or underground watering methods to avoid wetting leaves. * Apply benomyl or sulfur as disease appears. *Pesticide use and recommendations for various areas are constantly changing. Check with your County agent for current recommendations.

Strawberries

Using black plastic mulch provides needed water retention and discourages slugs and snails.

www.essentialgardenguide.com

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