Preventing Pests & Diseases in Tomatoes

Knowledge Center Tomatoes

Preventing Tomato Diseases

Home-Grown tomatoes are one of the most common crops grown in gardens today. They are a source of pride and beauty as well as a great addition to anything from summer salads to sandwiches that comes straight from your garden! These are best grown between the final May and September frosts in the north. It is best if a tomato is organic and is kept best and sickness free from infestations and outside bugs. This makes this a truly priceless addition to any garden collection.

There is an art to growing the perfect tomato, however, which requires keeping a precise eye on the plant to ensure its growing properly without becoming infected with pests or diseases. Plants should be free of common issues like being infected with larvae or other insects which can present signs of the plant carrying a disease. A quick reaction to help fix the problem is the best reaction to any sort of bug or problem found in a tomato plant. Responses should be quick and efficient using the most efficient tools, products, and methods available to preserve the health of the plant.

Common Tomato Pests & Diseases: 

There are many common garden pests and some of them love to specifically affect tomatoes. A few of them include the following:

Tomato Plant Diseases:

  • Powdery Mildew: Powdery Mildew that can be found on tomato plants forms on leaves in wet, shady places and can provide extra time and proper conditions for mildews to form on one's food. To avoid this water plants at the ground-level each morning at sunrise and pull the bad leaves off when signs of mildew begin to show to help preserve the plant and vegetables for longer after they are harvested.
  • Early Blight: Early blight is commonly spotted as a blemish within the leaves of the plants which is caused by Alternaria solani. These will appear ass dark brown spots with yellow rings rimming around the outside of them. Picking off leaves can help delay the disease from overtaking the plant if you catch the disease in the beginning phases of it infecting your plant. 
  • Speck & Spot: Speck & Spot are a bacterial disease that can cause black little speckles to appear on the leaf, stems, and fruit of the plant. Sometimes this is hard to distinguish from Early Blight as many of the spots appearing on the leaves and stems look very similar.  The appearance of larger veins in the tomato plant can differentiate between Early Blight and a case of Speck & Spot in a tomato plant. 
  • Fusarium Wilt: Fusarium Wilt caused by a soil-borne fungus that comes to infect the tomato plant by beginning with the root and stem of the plant. It continues from there and infects the whole plant if left untreated. Symptoms will show yellowed leaves without any black spots or other signs of issues at times. Symptoms will be the worst n warmer weather when the tomatoes are the closest to maturing. Be sure to keep your gardening environment sanitary as possible as the Fusarium Wilt seems to be spread through gardening tools and contaminated shoes or clothes in most cases, which makes it easy to spread from one plant to another very rapidly. 

Bugs & Pests in Tomato Plants:

  • Aphids: These clusters of tiny insects that may be spotted on the stem or the leaves of the tomato plants. These insects can be crushed with something small as a bare thumb. Remember that the larger infestations can affect and even kill the plants over time. Remember to take off the infested foliage and throw it away or remove it from the plant to avoid getting the entire plant infected.
  • Cutworms: Cutworms are tiny grub-like caterpillars that can feed on the stems of young plants throughout the night and can they can begin eating seedlings as low as at the ground level. You can create "collars" to put around the seedlings to keep them safe. You can make these "collars" out of anything from aluminum to paper or cardboard and back again. Make each one about 10" long and about 4" high, then bend them to form a cylinder and staple them to hold them in place. Each "collar" will sink about an inch into the soil around each individual seedling to keep them from being infected. 
  • Flea Beetles: Flea Beetles can be one of the most devastating pests or diseases that a tomato plant can attract. These little Beatles earn their name by resembling a flea and it can attack the plant from both sides. Adult Beatles will eat the plant's foliage leaving many small holes in the leaves and the larvae will feed on and destroy the roots of the plant to effectively kill the entire plant. To help avoid these pests from upsetting your tomato plants be sure to clear away weed and debris after each winter has passed and use row covers for each plant to help keep the Beatles and other bugs off of the vulnerable young plants till they are able to mature and grow on their own.
  • Hornworms: Hornworms are a destructive caterpillar that measures more than 3" in length for each bug and while sometimes they can just be picked off and thrown to the side, other times they can be much harder to get rid of. If there are only a few hornworms on the plants, they can be a pretty easy cleanup, but if many get intermixed with the plants it can become a much more complex job to get rid of them. If there are many a treatment like Bacillus Thuroingeinsis which is an organic, single-treatment control that helps control numerous other possible issues as well.


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  • Frances on

    You don’t show pictures so the article really doesn’t help


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