Wouldn’t it be ideal if after you planted your tomatoes, you could let them grow with a good touch of sun, regular feeding and water? However, growing vegetables is not that simple and tomatoes can succumb to many diseases.
Whether you are an experienced tomato grower or a beginner, these juicy delights can perish when attacked by tomato disease. But what is tomato late blight, how can you detect it, and can you take steps to protect your crops from the disease?
Here we share tips from two experienced gardeners who know how to identify, treat and prevent tomato late blight.
What is the tomato late mitigation?
Tomato blight is a disease that attacks the fruit and foliage of tomato plants, causing them to rot. However, to complicate matters a bit, there are two types of blight that can affect tomatoes.
Aileen Carroll, professional gardener and director of the Van Windens Garden Center in California, explains that there is fluff, known as Alternaria solani and downy mildew, known as Phytophthora.
“Unfortunately, they don’t have a cure, so your goal should be to completely prevent the infestation or manage it as best you can,” she adds.
Watch your potatoes too
Tomatoes are not the only vegetables that can be affected, as late blight can also damage potatoes.
How to Identify Early Tomato Blight
Mildew symptoms include black or brown spots, about a third of an inch in diameter, appearing on the leaves, stem or fruit. “You usually see signs of powdery mildew on the older leaves, so look at the leaves at the bottom of your tomato plant,” advises Carroll.
Carrie Spoonemore, co-creator of Park Seed’s From Seed to Spoon program, also says to “look for wilted leaves and yellowing around spots.”
How do tomatoes become infected with late blight?
The spores that cause mildew are airborne, but require moisture for germination and infection. “If conditions stay cool and moist for several days — like after a rain — then conditions are ideal for mildew spores to get hold of,” says Carroll.
How to Identify Tomato Late Blight
You can usually tell if your tomato plants have been affected by tomato late blight by checking the leaves. “Look for small, irregularly shaped green spots surrounded by yellow rings,” says Carroll. “These spots can quickly grow and turn brown or even purple. »
Spoonemore describes them as “water-soaked spots” that can “rapidly enlarge and kill entire leaves.”
Another indicator is to look for lesions on the stems: “Stems and petioles can develop oily-looking lesions from dark brown to black,” says Spoonemore. “The powdery mildew can also present firm, brown spots on green or ripe fruit. These spots often have a leathery texture.
How do tomatoes become infected with late blight?
Unlike mildew, where conditions are cool, downy mildew prefers a warmer climate. “The mildew is common in humid coastal environments,” says Carroll, “but less common elsewhere. This fungus likes high humidity and temperatures between 50 and 78°F.
How to Treat Tomato Blues
Taking the following steps can help treat blight and prevent it from spreading to healthy plants.
1. Remove the affected parts
Spoonemore recommends cutting off infected leaves and stems to reduce the spread of blight. However, to prevent the spread of disease, be sure to clean your clippers after use.
2. Proper disposal
“Don’t compost infected materials,” says Spoonemore, “throw them in the trash.” This will prevent disease from spreading when you apply compost to your garden.
3. Fungicidal treatment
Apply a fungicide treatment designed to treat blight, remembering to follow label directions. Carroll says, “It is possible to control the fungus by using a copper fungicide at the first sign of infestation,” although this will not solve the problem.
4. Improve air circulation
According to Carroll, ensuring good air circulation around your tomato plants is essential against late blight while allowing the leaves to dry out daily.
5. Mulching
Applying mulch will also help. “Use mulch to prevent soil from splashing onto the leaves, reducing spore transfer,” advises Spoonemore.
6. Watering
It is best to avoid putting too much moisture on the leaves, keeping the foliage dry. Carroll suggests sticking to drip irrigation or careful hand watering rather than overhead irrigation.
What are the best ways to prevent tomato blight?
There are several ways to prevent tomato blight to give your tomato plants the best chance of producing a healthy crop.
1. Crop rotation
“Rotate your crops and don’t plant tomatoes in the same spot for at least 2-3 years,” advises Spoonemore. The same applies to related crops, such as potatoes and eggplants, which she warns against planting in succession in the same soil.
2. Watering methods
As mentioned above, under “How to Treat Tomato Blight,” Spoonemore advises watering the base of the plant with drip irrigation or soaker hoses to keep the foliage dry. If the leaves get wet, they are more likely to succumb to a fungal disease.
3. Space and prune your plants properly
“Adequately space plants to ensure good air circulation and prune lower leaves to improve air circulation,” says Spoonemore. She advises against planting too close together, which can create a humid environment conducive to mildew.
4. Promote good hygiene
Keeping the garden clean and hygienic will reduce the risk of spoilage transmission. Spoonemore suggests: “Remove and dispose of plant debris and disinfect garden tools regularly. Make sure you don’t leave infected plant material in the garden or compost diseased plants.
5. Try growing your tomatoes indoors
It is more difficult to control the outdoor environment than indoors, so one way to reduce exposure to blight is to grow tomatoes indoors or in a greenhouse. Spoonemore also recommends being aware of other diseases that can be prevented by “ensuring that there is sufficient light, good ventilation and maintaining proper humidity levels.”
6. Grow late blight resistant tomatoes
One way to avoid tomato blight is to grow varieties that are resistant to the disease. Spoonemore recommends Fantastico Hybrid Grape Tomato and Nectar Hybrid Cherry Tomato.