Bacterial spot favors conditions of high humidity and warmer temperatures (75-85^oF / 24-30^oC) than that of bacterial speck. This disease can infect any part of the plant. The spots are small and generally brown and usually less than 1/8th inch (3mm) in diameter. Bacterial spot lesions may be confused with early blight, gray leaf spot or target spot lesions. It differs from these as no "halo" forms around the lesion as with target spot or early blight, does not form concentric rings nor do the individual lesions grow larger.

Both seed and infected plants can be a source of inoculum. Seeds should be treated prior to sowing with a mild bleach solution. This disease can also be spread by various mechanical means (handling, sprayer vapor, insects feeding). It enters the plant through the stomates or wounded created by handling, insects or wind driven sand.

To prevent, always treat seeds prior to sowing. Eliminate any volunteers or weeds in the field which may be infected. Clean up fields to remove all crop residues. Rotate fields to prevent carry-over from the previous season. Several bactericides or bactericide-fungicide combinations can be used to prevent or limit it's spread. Check with local state universities, county agents or nurseries for what bactericide/fungicide cobinations are recommended for your area.