Common Plant Problems
There are some common problems that may occur with the plants in your garden. Varying temperatures, weather patterns, and disease-causing insects can all affect your garden. We encourage you to regularly inspect your plants for pests and anything that looks abnormal on your plants. In some cases, it can be solved easily. Please see our guide below for a brief understanding of some common plant problems.
ANTHRACNOSE
BACTERIAL WILT
BLACK SPOT
BLOSSOM END ROT (BER)
CAT-FACING
CLUB ROOT
CORN SMUT
DAMPING OFF
DOWNY MILDEW
EARLY BLIGHT
FUSARIUM WILT
GRAY MOLD
LACK OF POLLINATION
LATE BLIGHT
LEAF SPOT
MOSAIC VIRUS
POTATO SCAB
POWDERY MILDEW
RUST
SPLITTING TOMATOES
VERTICILLIUM WILT
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Anthracnose
AFFECTED CROPS: Tomatoes, peppers, potatoes, onions, garlic, beans, lettuce, cucurbits, cotton, coffee, strawberries, raspberries, bananas, mangoes, citrus fruits, fruit trees.
CAUSED BY: A fungal disease in the genus Colletotrichum that germinates in wet environments.
HOW TO PREVENT: Choose disease-resistant varieties and seeds that have not been exposed to the disease.
HOW TO TREAT: Use fungicides with active ingredients like copper and sulfur. Neem oil also has been shown to have anti-fungal properties.
GENERAL INFO: Anthracnose generally affects plants in the eastern part of the U.S. It's caused by a fungal disease that leaves infected plants with dark, rotting spots on the fruit, leaves or stem, and can completely rot entire plants in a matter of a few days. This fungal disease can survive through the winter and will begin to develop and grow as the weather becomes hot and humid. Anthracnose is easily spread by wind, rain, garden tools, and insects.
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Bacterial wilt
AFFECTED CROPS: Cucumbers, muskmelons, squash, pumpkins, tomatoes, potatoes, eggplants, bananas, plantains.
CAUSED BY: A bacterium, Erwinia tracheiphila, that enters the plants through wounds. Striped and spotted cucumber beetles also carry and transmit the disease when feeding.
HOW TO PREVENT: Eliminate and control cucumber beetles immediately upon detection. Wash garden tools thoroughly to remove bacteria.
HOW TO TREAT: There is no treatment once a plant becomes infected. Infected plants will need to be destroyed immediately to prevent further spreading of the disease.
GENERAL INFO: Bacterial wilt is commonly spread by cucumber beetles. Not all cucumber beetles carry this bacterium; however, if they feed on an infected plant, they can then become a carrier and spread the bacterium to other plants when feeding. To identify if bacterial wilt is present, cut the stem at the base of the plant and suspend it in a glass of water. A whitish substance consisting of bacteria and slime will ooze from the stem within a few minutes if the plant is infected. Once a plant becomes infected, there is no treatment to control the disease.
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Black spot fungus
AFFECTED CROPS: Roses, flowers, fruits, vegetables, ornamental plants.
CAUSED BY: A fungal disease, Diplocarpon rosae, that thrives in wet, humid conditions.
HOW TO PREVENT: Plant in sunny areas, choosing locations with good air circulation.
HOW TO TREAT: Use fungicides with active ingredients like copper and sulfur. Neem oil also has been shown to have anti-fungal properties.
GENERAL INFO: Black spot fungus is most commonly known to affect roses, but it also can affect almost any common garden plant with leaves. Black spot typically starts as black splotches on the leaves that eventually become encircled by yellow rings. If not treated, the infected leaves will turn yellow and die. This fungus develops in wet, humid conditions and spreads quickly. It doesn't typically kill the host plant; however, if left untreated the infected plant will likely see a decline in vigor and growth.
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Blossom End Rot
AFFECTED CROPS: Tomatoes, peppers, cucumbers, eggplants, squash, watermelons, cantaloupes.
CAUSED BY: Uneven or infrequent watering can interfere with the plant's calcium uptake, leading to a calcium deficiency and ultimately blossom end rot. Rapid growth from too much fertilizer or high salt levels are other common causes.
HOW TO PREVENT: Always make sure the water reservoir is full. Always add dolomite when you set up your EarthBox system, and avoid using high nitrogen fertilizers. If desired, add 1 tsp. of calcium nitrate once per week in the water fill tube.
HOW TO TREAT: Remove any affected fruit immediately and discard to encourage the plant to set new fruit. Remove any water from the reservoir by tipping the system toward the overflow drain, and fill with a mixture of 1 gallon of water and 1/4 cup of pickling (hydrated) lime once only. Fill the reservoir the next day as usual. Check often to ensure the plant corrects itself, within 1-2 weeks.
GENERAL INFO: Blossom End Rot (BER) is a physiological condition that is often caused by environmental factors. It can occur in green or ripe fruit and will look like brown leathery spots on the bottom of the fruit initially, and black rotting wells if it becomes advanced. Because BER is not a fungus, it will not spread to other plants, but treatment options are limited. Prevention is key to combatting this condition. Take steps to ensure the reservoir remains filled and the plant has plenty of calcium.
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Cat-facing
AFFECTED CROPS: Tomatoes, strawberries, stone fruits.
CAUSED BY: Exposure to temperatures below 50° F during flowering and fruit set of the plant. Fertilizers high in nitrogen may also cause cat-facing.
HOW TO PREVENT: Some tomato varieties, especially heirlooms, are more prone to cat-facing. Avoid the problem by selecting resistant varieties. Protect transplants in cold weather or wait until temperatures are consistently warm to plant them.
HOW TO TREAT: There is no treatment once the fruit has developed cat-facing.
GENERAL INFO: Cat-facing is the malformation and scarring of fruit bottoms that resembles that of a cat's face. While unsightly, the fruit is still acceptable to eat if the scarring has not gone through the entire fruit. Since it's not a disease or fungus that will spread to other plants, continue letting the plant mature.
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Club root
AFFECTED CROPS: Broccoli, cauliflower, cabbage, turnips, rutabaga, kale.
CAUSED BY: A soil-borne fungus, Plasmodiophora brassicae, that infects plants through the roots.
HOW TO PREVENT: Sterilize garden tools and maintain a pH of 7.2-7.4.
HOW TO TREAT: There is no treatment once a plant becomes infected. Remove and destroy infected plants.
GENERAL INFO: Club root is a serious fungal disease that can affect many brassica crops. The disease can live in soil for up to 10 years, and infects plants through the roots. Infected roots become deformed and club-like, making it difficult for plants to absorb water and nutrients. As a result, plants appear wilted, have poor growth and the leaves can turn yellow, purple or brown. Club root fungal spores can be spread by wind, water and garden tools, so removing infected plants is crucial.
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Corn Smut
AFFECTED CROPS: Corn.
CAUSED BY: A fungus, Ustilago zeae, that enters the plant through injuries and abrasions.
HOW TO PREVENT: Remove and destroy garden debris after harvest and practice crop rotation. Avoid injuring plants and prevent insect damage by using an insecticide or insect net if insects are present.
HOW TO TREAT: There is no treatment once a plant becomes infected. Remove and destroy infected plants by bagging and discarding. Do not compost affected plants.
GENERAL INFO: Corn smut is a fungus that causes infected corn to form silver or greenish galls that consist of fungal material and enlarged plants cells. These galls can rupture and release fungal spores into the air. Spores are easily carried by the wind or rain to nearby plants where they enter through plant abrasions or injuries. The fungus can overwinter and survive for as long as 5-7 years. To limit the spread of the fungus, destroy infected plants and garden debris. Certain disease resistant corn varieties, like silver king and fantasia, should be planted until the disease is no longer present.
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Damping Off
AFFECTED CROPS: Vegetable and flower seeds and seedlings.
CAUSED BY: A soil-borne fungal disease consisting of several fungal species that affects seeds and seedlings.
HOW TO PREVENT: Provide good air circulation and avoid overwatering and overcrowding when planting seeds. Seed starting mix should be well-drained. Fungicides can be applied to the soil after planting to prevent the fungi from growing.
HOW TO TREAT: There is no treatment once a plant becomes infected. Prevention at the seed and seedling stage is key.
GENERAL INFO: Damping off is caused by several species of fungi that mostly affects the seeds and seedlings of new plants. This fungus lives in the soil and causes the stem and root tissues to rot below the surface. Infected plants may germinate and come up normally, but become water-soaked, mushy and die within a few days. High humidity levels, overwatering and planting too deeply will encourage fungi growth. Fungal spores can be transported in soil and on garden tools, but mature plants are rarely affected.
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Downy Mildew
AFFECTED CROPS: Fruits, flowers, vegetables.
CAUSED BY: A parasitic organism, Plasmopara viticola, that is produced in early spring and late fall in cool, wet conditions.
HOW TO PREVENT: Provide good air circulation between plants.
HOW TO TREAT: There is no treatment once a plant becomes infected. Downy mildew will likely clear up as temperatures increase.
GENERAL INFO: Downy mildew is caused by a parasitic organism that is closely related to algae. It needs water and cool conditions to survive and spread. Though downy mildew will likely clear up as temperatures rise, it can lead to stunted plant growth and leaf loss. Since downy mildew is spread through water, practicing good garden hygiene is key for prevention. Make sure plants have good air circulation.
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Early Blight
AFFECTED CROPS: Tomatoes, potatoes, eggplants, peppers, horse nettle, black nightshade, cabbage, cucumbers, zinnias.
CAUSED BY: A fungus, Alternaria solani, that thrives in hot, humid conditions.
HOW TO PREVENT: Provide good air circulation between plants. Maintain plant vigor as stressed plants are more susceptible to disease. Eliminate garden debris.
HOW TO TREAT: Use a fungicide at the first sign of the disease.
GENERAL INFO: Early blight is particularly common on older tomato and potato plants. Despite the name, plants can become infected at any point in the growing season. Early blight typically starts at the base of the plant and moves upward, causing dark spots on the leaves. Eventually the leaves will die and fall off, leaving the fruit exposed to sunscald. Fungal spores are spread by wind and rain, and enter the plant through wounds. Spores thrive in hot, humid conditions and can live in garden debris for a year or more.
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Fusarium Wilt
AFFECTED CROPS: Potatoes, tomatoes, eggplants, peppers, melons, cucurbits, ornamental flowers.
CAUSED BY: A soil-borne fungal disease, Fusarium oxysporum, that develops during hot, dry weather.
HOW TO PREVENT: Pretreat seeds with a fungicide to help prevent the disease from starting. Sterilize all garden tools and growing equipment. Use a pesticide to eliminate insects that may carry the disease.
HOW TO TREAT: Fungicides may help slow the fungus, but once a plant becomes infected there is no treatment that will completely stop the spread of the disease. Remove and destroy infected plants. Planting of resistant varieties will help.
GENERAL INFO: Fusarium wilt is a soil-borne fungal disease that restricts water flow to infected plants causing the plant to wilt and turn yellow. Plants will eventually die as they cannot adequately consume enough water. This fungus enters through plant roots and is spread by water, insects, and contaminated garden tools. Hot, dry weather and low soil moisture encourage the disease to grow and spread.
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Gray Mold
AFFECTED CROPS: Fruits, vegetables, flowers, trees, shrubs.
CAUSED BY: A fungus, Botrytis cinerea, that thrives in damp, cool weather.
HOW TO PREVENT: Provide good air circulation for plants to keep leaves dry. Promptly discard garden debris and use clean garden tools.
HOW TO TREAT: Use a fungicide spray at the first sign of the disease.
GENERAL INFO: Gray mold, aka botrytis blight, is a fungal disease that attacks a wide range of garden plants. This fungus is often present on plant debris or on old leaves and overripe fruit. Symptoms begin as brown or gray circles on plants that become fuzzy once the fungus develops spores. Fungal spores can spread long distances in the wind and can quickly rot healthy plant tissue. Gray mold thrives in damp conditions, so having good air flow between plants will help keep the leaves dry and prevent the fungus from forming.
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Lack of Pollination
AFFECTED CROPS: Any crop that bears fruit such as squash, cucumbers, melons, etc.
CAUSED BY: Attract natural pollinators to your garden, such as bees. Hand-pollinate if no pollinators are present.
HOW TO PREVENT: Provide good air circulation between plants. Maintain plant vigor as stressed plants are more susceptible to disease. Eliminate garden debris.
HOW TO TREAT: There is no treatment once the flower is past its fertilization period.
GENERAL INFO: Unfertilized fruit appears when the female flower of the crop has not been pollinated. The small fruit that grows below the female bud will mature slightly and then suddenly begin to shrivel and die off if the flower has not been pollinated. Attracting natural pollinators, such as bees, to your garden will help ensure pollen is dispersed to various flowers. If you lack pollinators, the open male flowers may be removed and used to hand-pollinate up to 3 female flowers each to ensure fruit sets and develops.
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Late Blight
AFFECTED CROPS: Tomatoes, potatoes, eggplants, peppers.
CAUSED BY: A fungus, Phytophthora infestans, that thrives in humid conditions with moderate temperatures.
HOW TO PREVENT: Provide good air circulation between plants.
HOW TO TREAT: Fungicides may help slow the fungus, but once a plant becomes infected there is no treatment that will completely stop the spread of the disease. Remove and destroy infected plants.
GENERAL INFO: Like its name implies, late blight occurs late in the growing season. Water-soaked dark spots with a white fungal growth will appear on the leaves, and eventually infect the entire plant. Fungal spores travel by wind, easily wiping out entire crops. Late blight was responsible for the Irish potato famine in the mid-1800's. Disease development is mostly dependent on weather conditions, and thrives in humid yet cooler conditions. Fungicides may be used to help prevent the fungus from starting, but it's not been shown to completely stop the disease once a plant becomes infected.
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Leaf Spot
AFFECTED CROPS: Fruits, vegetables, flowers.
CAUSED BY: Either a fungus, Septoria lycopersici, or bacteria that both thrive in damp conditions.
HOW TO PREVENT: Provide good air circulation between plants. Remove any diseased leaves right away. Dispose of garden debris regularly.
HOW TO TREAT: To control fungal leaf spot, use a fungicide spray. For bacterial leaf spot, there is no treatment once a plant becomes infected.
GENERAL INFO: Leaf spot is a common disease that affects many fruit and vegetable plants. The disease can be caused by either a fungus or bacterial infection. Both kinds of leaf spots are similar in appearance, with brown or black water-soaked spots on plants. These spots can grow in humid conditions, causing entire leaves to yellow and die. Wind and water spreads the disease, and it can overwinter on weeds and garden debris. Taking steps to keep plants dry by providing good air flow.
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Mosaic Virus
AFFECTED CROPS: Flowers, vegetables.
CAUSED BY: A viral disease.
HOW TO PREVENT: Eliminate garden insects promptly. Use only clean garden tools, and wash hands frequently when gardening. Remove and destroy any infected plants or garden debris.
HOW TO TREAT: There is no cure for mosaic viral disease.
GENERAL INFO: Mosaic virus is caused by a viral disease that affects many common vegetable and flowering plants. It can be difficult to distinguish mosaic virus from other common viruses or plant deficiencies as the symptoms are so similar. Once infected, plant leaves may begin to look mottled, curled or malformed. The overall plant may look yellow and have stunted growth. Fruits may ripen unevenly and form yellow rings or internal brown spots. The disease can survive in the soil or on plant debris for at least 2 years.
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Potato Scab
AFFECTED CROPS: Fruits, vegetables, flowers, shrubs, trees.
CAUSED BY: A fungal disease that consists of a variety of fungal species.
HOW TO PREVENT: Provide good air circulation. Remove any diseased foliage or plant debris on the ground. Eliminate garden insects promptly.
HOW TO TREAT: Use a sulfur or copper fungicide at the first sign of infection.
GENERAL INFO: Potato scab is caused by a bacterium that affects potatoes and other root vegetables. Infected tubers grow raised, brown patches that resemble warts. Potato scab enters through wounds on the tuber skin or pores in the stem. The bacterium is most prevalent and can live indefinitely in alkaline soils. Lowering the soil's pH to 5.2 or below can help suppress the disease. The bacterium is spread by wind and water. It can even survive in an animal's digestive tract and be spread through manure.
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Powdery Mildew
AFFECTED CROPS: Fruits, vegetables, flowers, shrubs, trees.
CAUSED BY: A fungal disease that consists of a variety of fungal species.
HOW TO PREVENT: Provide good air circulation. Remove any diseased foliage or plant debris on the ground. Eliminate garden insects promptly.
HOW TO TREAT: Use a sulfur or copper fungicide at the first sign of infection.
GENERAL INFO: Powdery mildew is a common fungal disease that affects many plant varieties. It usually appears later in the growing season and can easily be spread to nearby plants by wind, water and insects. Infected leaves become covered with a white or gray powder-like substance. Powdery mildew can also spread to the fruit or flower buds of the plant, preventing them from opening or growing. The disease tends to favor warm climates with high humidity, so providing good air flow around plants will help with disease prevention.
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Rust
AFFECTED CROPS: Roses, daylilies, snapdragons, hollyhocks, tomatoes, beans, peas, berries, asparagus, corn, lawns.
CAUSED BY: A fungal disease, Phragmidium spp., that thrives in warm, humid conditions.
HOW TO PREVENT: Provide good air circulation between plants. Remove and destroy infected leaves and debris.
HOW TO TREAT: Use a sulfur or copper fungicide at the first sign of infection.
GENERAL INFO: Rust is a fungal disease that can attack a plant's leaves, stems, flowers and fruit. Symptoms of rust can vary by the type of plant infected, but most develop reddish brown blisters that release spores. Fungal spores are then carried by wind or water to nearby plants. Severe rust infections can turn leaves yellow and even cause the plant to become stunted and die. Rust needs wet conditions to thrive.
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Splitting Tomatoes
AFFECTED CROPS: Tomatoes.
CAUSED BY: A severe lack of water followed by too much water, or sudden changes in weather.
HOW TO PREVENT: Be sure the water reservoir is always filled. Move plants inside a shed or garage if temperatures are forecasted to drop significantly; or if heavy, cool rainfall is expected after a long period of dry, hot weather.
HOW TO TREAT: There is no treatment once tomatoes are split.
GENERAL INFO: Splitting tomatoes is a common problem most tomato will gardens face at one point or another. Tomatoes will split or crack if there is a period of dry weather followed by a period of soaking rain, but eventually they may repair themselves by scabbing over. Regularly keeping the water reservoir full can help prevent tomatoes from splitting. The good news is, splitting tomatoes are still edible and the taste shouldn't be affected.
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Verticillium Wilt
AFFECTED CROPS: Tomatoes, watermelons, strawberries, spinach, rutabaga, radishes, potatoes, peppers, mint, eggplants, cucumbers, cotton, cabbage, brussels sprouts, cantaloupe, honeydew melons, cherries, peaches, apricots.
CAUSED BY: Several fungal species of the Verticillium spp. that thrive in cool, wet climates.
HOW TO PREVENT: Water regularly and deeply to increase plant vigor. Remove any infected leaves or debris immediately. Practice crop rotation yearly.
HOW TO TREAT: There is no treatment once the plant is infected.
GENERAL INFO: Verticillium wilt is a fungal disease that affects a wide variety of garden plants. This fungus lives in the soil and thrives in cool, moist environments. It enters through the plant's roots, and clogs the plant's vascular system, depriving it of water. Leaves of infected plants will look wilted and eventually turn brown and die. Verticillium wilt can overwinter for many seasons.