Anthracnose fungal disease

MoonShadows

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Messages
741
Location
Stroudsburg, PA
First Name
Jim
Hardiness Zone
6a
#1
Last season was wet and cold, so when my tomatoes began to ripen and develop lesions just before they were ready to be picked, I chalked it up to the constant cool and wet weather. Now, in retrospect, I think the problem was Anthracnose fungal disease. Anthracnose can attack any part of a plant from the stem to the leaves to the fruit or all parts. Since my tomato stems and foliage always looked healthy and dark green with no signs of problems, that also led me to believe my tomatoes were a victim of our terrible 2017 weather.

Most common signs of Anthracnose in tomatoes:
  • Infections are visible only on ripe and over ripe tomatoes
  • Fruit spots are sunken and round
  • Mature fruit spots have a black center
  • Fruit spots produce pink spores with moisture
  • No visible spots on leaves and stems

Here are some examples (not mine, but examples I found on the internet. Mine looked exactly the same as the fruit began to ripen:

anthracnose-on-tom-fruit-443.jpg Anthracnose1227.jpg bacterialspot3_600px.jpg

Generally found in the eastern part of the United States, anthracnose is caused by fungi in the genus Colletotrichum, a common group of plant pathogens that are responsible for diseases on many plant species. Infected plants develop dark, water soaked lesions on stems, leaves or fruit. The centers of these lesions often become covered with pink, gelatinous masses of spores especially during moist, warm weather. Anthracnose can reduce a beautiful harvest into rotted waste in just a few days.

The fungal disease overwinters in and on seeds, soil and garden debris. Cool wet weather promotes its development, and the optimum temperature for continued growth of the spores is between 75-85˚F. Moisture is required for development and germination of the fungus as well as for infection of the plant. It is spread by wind, rain, insects and garden tools.

Treatment
  • Choose resistant plant varieties when possible and use western grown seeds which have not been exposed to the disease.
  • If this fungal problem is common, do NOT save your own seed from plantings.
  • To avoid spreading the disease, keep out of gardens when plants are wet and make sure to disinfect all garden tools (one part bleach to 4 parts water) after use.
  • Do not compost infected leaves, fruit or stems and thoroughly clean up garden areas in the fall, after harvest, to reduce over wintering sites for the fungal spores.
  • Safely treat most fungal and bacterial diseases with SERENADE Garden. This broad spectrum bio-fungicide uses a patented strain of Bacillus subtilis that is registered for organic use. Best of all, SERENADE is completely non-toxic to honey bees and beneficial insects.
  • Liquid copper sprays and sulfur powders should be applied weekly, starting when foliage begins to develop in the early spring and continuing throughout the growing season. Spray early in the day, and avoid applications during hot weather. Seeds may also be treated prior to planting.
  • Neem oil spray is an organic, multi-purpose fungicide/insecticide/miticide that kills eggs, larvae and adult stages of insects as well as prevents fungal attack on plants. Apply early, at the first sign of spring budding, every 7-14 days as a preventative measure or on a 7-day schedule until existing problems are eliminated.
 

MoonShadows

Administrator
Staff member
Joined
Dec 3, 2017
Messages
741
Location
Stroudsburg, PA
First Name
Jim
Hardiness Zone
6a
#3
Yeah, I ordered a container of Bonide 811 Copper 4E Fungicide
71G9xIg-yFL._SX522_.jpg
  • Copper formulations protects a wide range of plants from turf to veggies, to fruit and flowers from a host of listed diseases
  • Great for Blight! Suitable for organic gardening
  • For indoor and outdoor use
  • Won't harm beneficial insects
One thing I did learn and didn't know before is you should not use the same fungicide all the time, but use different types so the fungi don't become resistant.
 

MoonShadows

Administrator
Staff member
Joined
Dec 3, 2017
Messages
741
Location
Stroudsburg, PA
First Name
Jim
Hardiness Zone
6a
#5
I really don't like using it at all, but I also don't like throwing away 100's of tomatoes. Just as they were getting ripe, these lesions would show up. It was so frustrating. What was strange is I had this affect my Beefstakes, San Marzanos and grape tomatoes, but not my cherry and Campari tomatoes that were planted right in the middle. I have to look them up; some tomatoes are more resistant than others to Anthracnose.