Late blight on tomatoes in Denver? Rainy weather in Denver’s usually hot, dry community brings up the question of fungus. We don’t usually worry about this problem in Denver. Fungus like that which causes late blight tomatoes grows well in wet weather.
The Denver gardener would do well to watch for signs of late blight tomatoes and potatoes. This fungus spreads quickly and can damage a whole field crop. A gardener with late blight tomatoes should act quickly to see that the fungus does not spread to other plants.
Late blight tomatoes can be recognized by lesions on the leaves, fruit and stems. These lesions begin with a green appearance but turn black in damp weather. The entire plant will take on a wilted appearance in later stages. Late blight tomatoes will often develop a white mold which may disappear in dry weather.
Late blight tomatoes are a greater concern due to a strain of late blight from Mexico which first appeared in the early 90’s. This late blight tomatoes disease strain is more resistant to fungicides than previous strains.
Another problem is that big box stores are selling tomato plants that are already infected with the late blight tomatoes fungus. This, combined with recent moisture is a double whammy for developing late blight tomatoes fungus. Avoid late blight by buying at reputable greenhouses and checking plants carefully before purchase.
In a rainy season like the one we are experiencing in Denver, gardeners should take care not to over water their plants. In Denver, we are used to the hot sun drying out our soil quickly. Denver gardeners are used to taking measures to retain water, not keep plants dry.
Raised bed gardening with good drainage should keep late blight tomatoes from developing. Raised beds or containers that drain well allow soil to dry between waterings. Soil that retains water makes it easier for late blight tomatoes and potatoes to grow fungus.
Late blight tomatoes control may ironically mean more frequent watering. This is due to quick draining and drying containers. Excess water usage is a thorn in the side of Denver organic gardeners but when the alternative is throwing away good food the choice is clear.
Those unable to save late blight tomatoes should not use the spoiled tomatoes in their compost bin. The fungus stain from Mexico may thrive in warm wet compost. Throw late blight tomatoes, potatoes and plants out with the trash to prevent infection of next years crop.