tems and fruit if weather conditions are good. Ideal conditions for late blight development are cool nights, moderately warm days, abundant moisture. Hot and dry weather reduces disease development.Gray Leaf Spot (fungal : Stemphylium solani)First infection appears as small, brownish-black specks on the lower leaves that extend through to the under surface of the leaf. These spots usually remain small, but may enlarge until they are about one-eighth inch in diameter. The spots become glazed and the centers crack. Infected leaves usually die and fall off. spots may also form on the stems of the host plant.Leaf-MoldCausal Agent(s): (fungal - Fulvia (Cladosporium) fulvum)Leaf mold is usually first observed on older leaves near the soil where air movement is poor andhumidity is high. At first, diffuse whitish spots appear on the upper surfaces of older leaves; theserapidly enlarge and become yellow. Under humid conditions, the lower surface of these spotsbecome covered with a gray, velvety growth of the spores produced by the fungus. When conditionsare proper for fungal development, large areas of the field are infected, plants are weakened and thecrop is greatly reduced. The fungus produces abundant spores during periods of high temperatureand very high relative humidity. Infection occurs readily, and the disease becomes established in thefields quickly. The best control of this disease is by using a preventative fungicide program at 7 to 10day intervals, the same as used for late and early blight control. Buckeye RotCausal Agent(s): (fungal - Phytophthora parasitica)This disease occurs on tomato mainly on the fruit, particularly where it touches the soil. The fungus isdifferent from the one causing late blight, which affects both leaves and fruit. Buckeye rot is firstnoticed as a light green water-soaked area on the fruit. Later, dark zonate bands can be seen on thesurface of affected areas. The surface of the lesion is usually smooth and...
