Tomato plants become more susceptible with age particularly at fruiting. Early blight can develop quite rapidly under humid warm conditions and is more severe when plants are stressed by poor nutrition, drought, nematode attack or a heavy fruit load. Seriousness of early blight is dependant on weather conditions and crop variety. Periods of warm rainy weather, with temperatures between 21-24☌ favour outbreaks of early blight. Infection occurs in warm, humid weather with heavy dews or rain. Spores are formed on infected plant debris at the soil surface or on active lesions over a fairly wide temperature range, especially under alternating wet and dry conditions.
It can also be carried on tomato seed and in potato tubers. This fungus is universally present in fields where susceptible crops have been grown. Leaf spots of early blight are circular, up to 1.2 cm in diameter, brown, and often show a circular pattern, which distinguishes this disease from other leaf spots on tomato.Įarly blight is caused by the fungus, Alternaria solani, which survives in infected leaf or stem tissues diseased potato tubers on or in the soil and in infected tomato fruits. Late blight lesions are lighter, smaller and they do not have the circular ridged bands that early blight has.Įarly blight on tomato leaf. The spot is usually brown to black, firm, depressed and has distinct concentric rings.Įarly blight is sometimes confused with Late blight. Typical fruit spots occur at the stem-end as a rot that radiates out from the area of attachment between the calyx and the fruit. Entire plant could be defoliated and killed. Leaf spotting first appears on the oldest leaves and progresses upward on the plant. When older seedlings are infected, stem lesions (spots) usually are restricted to one side of a stem and become elongated and sunken on stems and leaf petioles.Īffected leaves exhibit brown spots with concentric rings. Affected seedlings are stunted and may wilt and die. On young seedlings, collar rot may develop - it is characterized by girdling of the stem at the base of the plant. In seedbeds, pre- and post-emergence damping-off occurs. Increased damage may occur by secretions of toxins by pathogens.Īll above ground parts of the plant can be affected. Infection first occurs during periods of warm, rainy, humid weather. It is of particular importance in warm dry areas.
Early blight potato diseases series#
Entire plant could be defoliated and killed Ⓒ Early blight ( Alternaria solani )symptoms on tomato leaf Ⓒ Clemson University - USDA Cooperative Extension Slide Series ( IntroductionĮarly blight is one of the most common and serious diseases of potato and tomato. Affected leaves exhibit brown spots with concentric rings. Leaf spots of early blight are circular, up to 1.2 cm in diameter, brown, and often show a circular pattern, which distinguishes this disease from other leaf spots on tomato.
Ⓒ Allen Stevens and Jon Watterson, Seminis Vegetable Seeds, Inc.Įarly blight on tomato.
The spot is usually brown to black, firm, depressed and has distinct concentric rings. Reproduced from University of Minnesota Extension.Įarly blight symptoms on tomato fruits. Internally, the tissue shows a brown to black corky, dry rot, usually not more than 6 mm. There is usually a well defined and sometimes slightly raised margin between healthy and diseased tissue. Lesions are usually slightly sunken, circular or irregular, and vary in size up to 2 cm in diameter. CAB International, Wallingford.Įarly blight symptoms on tomato fruit Ⓒ A.A.Seif, icipeĮarly blight results in surface lesions that appear a little darker than adjacent healthy skin. Reproduced from the Crop Protection Compendium, 2004 Edition. Varela, icipeĮarly blight symptoms on okra leaf Ⓒ M.
0 kommentar(er)
