Primer on plant problems, how to treat them! Part One
Your garden is off to a great start this season and everything's looking great, you don't have a care in the world and then: Whack. All of a sudden your prize tomato plants are turning wicked colors of yellow or brown, perhaps dropping their leaves as we
- DAMPING OFF
Symptoms: Very young (newly seeded) flower and vegetable seedlings either fail to come up or rot off at soil level soon after the emerge.
Cause: A variety of bad fungi (rhizoctona, fusarium, Phytophthora and a few others) that live in the upper layers of seed-starting (or garden soil) bed.
Remedy: I think most gardeners know that using a sterilized potting mixture when planting seeds indoors is a fail-proof method in avoiding this type of disease problem, but what about outside in the open soil? There are a few things you can do, such as building raised beds to ensure good drainage (since these disease fungi are activated by damp soil). Also, compost has scientifically proven disease-fighting power that, when used as a seedbed material, drastically eliminates any chance of seedlings damping off. Just be sure to lay down about a one-inch layer over the bed and don't mix it into the soil. Plant your seed right on top of the mix. I also use sterilized soil-less mixtures to cover the seeds after planting to insure that they will sprout in a near-sterile environment.
-POWDERY MILDEW
Symptoms: Whitish-gray powdery coating on leaves, buds, and often blossoms of vegetables (cucumbers are notorious), and flowers (roses, lilacs and phlox). In severe cases, leaves may turn yellow and become deformed and buds may fail to open.
Cause: Spores of bad fungi (erysiphe, sphaerotheca to name a few) that are spread by wind and encouraged by hot, dry days and cool nights .
Remedy: You can save yourself plenty of headaches by choosing plant varieties that are resistant to powdery mildew if they are available. That not always being the case, you'll need to take other action. It actually thrives in dry conitions. A neat and easy trick is to actually spray the plants with a strong spray of water during the early stages of powdery mildew. This tactic alone might be enough to thwart an infection, as you will literally knock the disease spores off the plant. If that doesn't work, a great homemade solution to combat powdery mildew can be made by mixing one tablespoon of baking soda, one tablespoon of vegetable oil, and a single drop of dishwashing soap in one-gallon of water. Shake the mixture well and apply with a pump sprayer on the plants until they are saturated and dripping. This is a mixture that I'll use on vegetable crops, but often flowers and shrubs need stronger fungicide. Products like Immunox and Daconil work very well.
- ANTHRACNOSE
Symptoms: Sunken spots (up to a half-inch in diameter) appear on the skin of ripe tomatoes affected by this disease. The center of the spots usually darkens and forms concentric rings.
Cause: Colletotrichum coccodes fungus.
Remedy: Anthracnose thrives in warm, wet conditions, so try and avoid overhead irrigation where possible. To prevent spreading the disease, do not work in the garden when plants are wet. Be sure to stake, trellis, or cage your tomato plants so that the fruit is kept away from the soil surface. Make sure to harvest tomatoes as soon as they are ripe and when you find an anthracnose-infected tomato (it's inedible by the way), be sure they are tossed into the garbage pail (do not compost).
-RUST
Symptoms: Orange-yellow, brown, or purple pustules appear on the underside of leaves. Affects many types of plants, but beans, roses, geraniums, hollyhocks and snapdragons seem to catch the worst cases of rust. Eventually, the upper leaf surface becomes mottled with yellow patches, and the leaves shrivel and fall off. Severely infected plants become stunted and may die.
Cause: Many species of fungi that belong to the Uredinales order.
Remedy: This is a fungus that thrives in warm, wet conditions, so again, avoid overhead irrigation in favor of drip irrigation wherever you can. Water in the morning rather then sending the plants into the evening with wet foliage. Allow plenty of room for air to circulate and pluck any infected leaves as soon as you see them. Strict garden sanitation is important in controlling this disease. There are several chemical fungicide products to use in controlling rust, depending on the type of plant.
- DAMPING OFF
Symptoms: Very young (newly seeded) flower and vegetable seedlings either fail to come up or rot off at soil level soon after the emerge.
Cause: A variety of bad fungi (rhizoctona, fusarium, Phytophthora and a few others) that live in the upper layers of seed-starting (or garden soil) bed.
Remedy: I think most gardeners know that using a sterilized potting mixture when planting seeds indoors is a fail-proof method in avoiding this type of disease problem, but what about outside in the open soil? There are a few things you can do, such as building raised beds to ensure good drainage (since these disease fungi are activated by damp soil). Also, compost has scientifically proven disease-fighting power that, when used as a seedbed material, drastically eliminates any chance of seedlings damping off. Just be sure to lay down about a one-inch layer over the bed and don't mix it into the soil. Plant your seed right on top of the mix. I also use sterilized soil-less mixtures to cover the seeds after planting to insure that they will sprout in a near-sterile environment.
-POWDERY MILDEW
Symptoms: Whitish-gray powdery coating on leaves, buds, and often blossoms of vegetables (cucumbers are notorious), and flowers (roses, lilacs and phlox). In severe cases, leaves may turn yellow and become deformed and buds may fail to open.
Cause: Spores of bad fungi (erysiphe, sphaerotheca to name a few) that are spread by wind and encouraged by hot, dry days and cool nights .
Remedy: You can save yourself plenty of headaches by choosing plant varieties that are resistant to powdery mildew if they are available. That not always being the case, you'll need to take other action. It actually thrives in dry conitions. A neat and easy trick is to actually spray the plants with a strong spray of water during the early stages of powdery mildew. This tactic alone might be enough to thwart an infection, as you will literally knock the disease spores off the plant. If that doesn't work, a great homemade solution to combat powdery mildew can be made by mixing one tablespoon of baking soda, one tablespoon of vegetable oil, and a single drop of dishwashing soap in one-gallon of water. Shake the mixture well and apply with a pump sprayer on the plants until they are saturated and dripping. This is a mixture that I'll use on vegetable crops, but often flowers and shrubs need stronger fungicide. Products like Immunox and Daconil work very well.
- ANTHRACNOSE
Symptoms: Sunken spots (up to a half-inch in diameter) appear on the skin of ripe tomatoes affected by this disease. The center of the spots usually darkens and forms concentric rings.
Cause: Colletotrichum coccodes fungus.
Remedy: Anthracnose thrives in warm, wet conditions, so try and avoid overhead irrigation where possible. To prevent spreading the disease, do not work in the garden when plants are wet. Be sure to stake, trellis, or cage your tomato plants so that the fruit is kept away from the soil surface. Make sure to harvest tomatoes as soon as they are ripe and when you find an anthracnose-infected tomato (it's inedible by the way), be sure they are tossed into the garbage pail (do not compost).
-RUST
Symptoms: Orange-yellow, brown, or purple pustules appear on the underside of leaves. Affects many types of plants, but beans, roses, geraniums, hollyhocks and snapdragons seem to catch the worst cases of rust. Eventually, the upper leaf surface becomes mottled with yellow patches, and the leaves shrivel and fall off. Severely infected plants become stunted and may die.
Cause: Many species of fungi that belong to the Uredinales order.
Remedy: This is a fungus that thrives in warm, wet conditions, so again, avoid overhead irrigation in favor of drip irrigation wherever you can. Water in the morning rather then sending the plants into the evening with wet foliage. Allow plenty of room for air to circulate and pluck any infected leaves as soon as you see them. Strict garden sanitation is important in controlling this disease. There are several chemical fungicide products to use in controlling rust, depending on the type of plant.
posted by blogger at
Saturday, June 24, 2006
