ALS – Alternaria Leaf Spot

Scientific Name: Alternaria brassicicola, Alternaria cucumerina, Alternaria dauci

Type: Fungus

Alternaria Leaf Spot, also known Alternaria Leaf Blight, is a world-wide fungal disease that affects the growth of broccoli, Brussels sprouts, cabbage, cantaloupes & melons, carrots, cauliflower, cucumbers, kale, kohlrabi, pumpkins, radishes, rutabaga, squash, tomatoes, turnips, and watermelons. Symptoms may first develop on young plants where leaf spots develop, plants become stunted, and damping off may occur. Greenish-brown lesions appear on the leaves, and turn from dark brown to black spots. The disease may appear on the leaves at any stage and start off as concentric circles and mature to lesions with a bulls eye appearance. The leaves curl, turn yellow, wither, and eventually die off, and heavy infestations may cause complete defoliation. The infected plants should be removed to avoid further infestation. Increase space between the plants to maximize air flow and drying of the leaves. The disease is favorable when temperatures are 75-82 F and usually occur when moisture and humidity are very high. Plan on using a 3 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil for 8 years. Fungicides can help manage the disease. The best option is to use disease resistant varieties.

BER - Blossom End Rot

Type: Physiological Disorder

Blossom End Rot is a physiological disorder that affects tomatoes. As tomatoes begin to ripen, black spots on the bottom of the tomato appear. The tomatoes affected by blossom end rot should be picked and discarded. The cause is a calcium deficiency. The condition is not caused by a lack of calcium in the soil, but because the plant is unable to take up the calcium that is already in the soil because of drought or erratic watering. It is most common when the growing season starts out wet and then becomes very dry when tomatoes are setting. Plants are unable to absorb calcium because the soil is too wet or too dry, there is excessive nitrogen in the soil, roots are damage during cultivation, soil pH is either too high or too low, cold soil, and high levels of salts in the soil. Keep consistent levels of moisture in the soil throughout the growing season. Allow soil to warm before planting. Use mulch, such as Red Tomato Mulch, to minimize evaporation and to help maintain consistent moisture in the soil. Test soil so pH is at 6.5. Use Tomato Rot Stop to prevent calcium deficiency. The best option is to use disease resistant varieties.

FF – Fusarium Wilt (Race 2)

Scientific Name: Fusarium oxysporum

Type: Fungus

Fusarium Wilt, Race 2, is a world-wide fungal disease that affects the growth of tomatoes. It is one of the most devastating of all soil-borne diseases. Race 2 is found in Arkansas, Florida, New Jersey, and Ohio in the United States. It attacks the roots of the plants and moves up the stems. Symptoms include yellowing and browning of the older bottom leaves, stunting, and wilting. Often the entire plant will die. Usually little or no fruit develops. The infected plants will produce inferior and unmarketable tomatoes. It can cause significant yield loss and even total crops losses. If you stick with Fusarium Wilt Resistant tomato varieties you don’t have to worry. Many of the older heirlooms don’t have any resistance to the disease, so if you grow these then you should keep an eye out for it. The infected plants should be removed and burned to avoid further infestation. Plan on using a 5 to 7 year crop rotation and avoid planting in the same location, year after year, as the disease can survive in the soil up to 10 years. The best option is to use disease resistant varieties.

GW – Gray Wall

Type: Physiological Disorder

Gray Wall, also referred to as Blotchy Ripening, is a physiological condition associated with environmental factors that affects the growth of tomatoes. Symptoms include black to dark brown tissue in the walls of the tomatoes. Tomatoes look splotchy and mottled resulting in uneven ripening. The grayish splotches on tomato surfaces may even collapse inward – thus the condition’s name. The inside of an affected tomato may also have grayish, yellowish, brownish, or greenish patches internal whitening and yellow shoulders. It does not affect the stems and leaves of the plant. It can cause substantial yield loss and total crop loss, if not controlled. It is caused by extreme heat, high humidity, temperature fluctuations, clouds during hot weather, excessive nitrogen, lower levels of potassium, and high soil moisture. Make sure plants aren't heavily shaded, using a good irrigation program, and that the soil is not compacted around the plants. Test the soil each year for nitrogen and potassium. Grow varieties that are resistant to TMV. The best option is to use disease resistant varieties

V – Verticillium Wilt

Scientific Name: Verticillium dahliae

Type: Fungus

Verticillium Wilt is a soil-borne disease that affects the growth of lettuce, peppers, spinach, and tomatoes. This disease is most common in the United States and Europe. In lettuce symptoms include wilting of the lower leaves and then the outer leaves turn yellow, wilt and die. Brown and black streaks appear on the taproot and crown The disease can cause substantial yield loss and total crop loss. It is a seed-borne disease that is spread by farm equipment, wind, and water. The infected plants should be removed and burned to avoid further infestation. The virus can live in weeds, so use weed management techniques. The fungus is very difficult to eradicate once it has been introduced into a field. Plan on using a 4 year crop rotation and avoid planting in the same location, year after year, and can survive in the soil for 14 years. Keep the fields weed free. Deep tilling may be helpful in managing the disease. Thoroughly clean equipment after working in a field. Fumigate fields with methyl bromide. The best option is to use virus-free seeds and disease resistant varieties