Tomato Plant Diseases in Arkansas

Fungal Disease

• Fungus breeds in warm, wet conditions, and Arkansas temperatures in the tomato growing season can average 90 degrees Fahrenheit or more. Fungal diseases can cause damage to leaf, stem, root and fruit. Buckeye rot is a disease of fruit that forms rings in the flesh. Early blight is a nationwide fungal disease that survives in seed and overwinters in plant debris. It grows fruiting bodies when temperatures are warm and humidity is high --- in Arkansas this period runs from July until late August or even September. Southern blight survives in soils where tomatoes have been grown consistently. Verticulum wilt can be found in tomatoes grown in high pH soils and causes wilting in the day, but the plant recovers at night. Eventually it spreads to stems creating a hollow, pithy center.

Bacteria Disease

• Bacterial speck and bacterial spot are two of the more common Arkansas tomato diseases. They are caused by different bacteria, but primarily affect the fruit and leaves. Speck causes raised imperfections which are carried in seed and manifest in temperatures of 65 to 75 degrees Fahrenheit. Spot shows up as scabby spots and overwinters in plant debris. It arises in warmer temperatures of 75 to 85 degrees Fahrenheit, which in Arkansas begin in May. Bacteria canker infests tomatoes systemically, and begins by wilting the lower leaves of the plant.

Virus Diseases

• Mosaic diseases are commonly found on tomatoes and other crop fruits. Cucumber mosaic and tobacco mosaic are viral diseases that causes distorted leaves and spotting or mottling in the color. The leaves may turn light greenish-yellow or darker in patterns. Both kinds of mosaic disease are communicable to tomatoes and cause yellow stunted plants. The leaves become deeply divided and fern-like. Both diseases are often transferred mechanically or on clothing.

Deficiency Diseases

• Chlorosis is an iron deficiency and is caused by improper pH levels and shows up as a yellowing on the leaves and finally on the fruit. Blossom end rot can cause the loss of fruit and is a deficiency of calcium. Moisture stress and too much nitrogen fertilizer are contributing factors. Growth cracks, cat face and leaf roll also show up as disfiguring problems on tomatoes, and are caused by excess rain, cool weather at bloom and overly rapid growth.