Early blight of cherry tomatoes affects production; how can it be prevented and controlled?

    Early blight is a major disease of cherry tomatoes, widely distributed and commonly occurring, mainly occurring in cherry tomato field plots planted in the open field in autumn, and also occurring from time to time in protected cultivation. Generally, 30%-50% of plants are diseased, and in severe cases 100% are affected. Some branches and leaves die due to early blight, significantly affecting cherry tomato production.  

Early blight of cherry tomatoes

    Early blight mainly damages leaves, and in severe cases also infects petioles, branches and stems. When leaves are infected, small brown necrotic spots first appear, then become nearly circular brown diseased necrotic spots with concentric rings, with yellow-green edges; multiple lesions connect with each other, causing cherry tomato leaves to turn yellow and die. When petioles, branches and stems are infected, oval to irregular brown necrotic spots appear, obviously sunken, with concentric rings, rough surface, and easily broken at the diseased part. When the air is humid, the surface of the lesions has gray-black moldy material, namely the pathogen's conidiophores and conidia.  

    Prevention and control methods:

    1. Apply sufficient organic base fertilizer, together with increased application of phosphorus and potassium fertilizers. During the growing period, topdress and water in a timely manner to avoid premature aging of cherry tomato plants due to nutrient deficiency and to enhance disease resistance. 

    2. Do a good job of field sanitation. After harvest, thoroughly remove diseased residual tissues and fallen leaves; during the growing period, promptly remove diseased leaves to reduce sources of inoculum. 

    3. In the early stage of the disease, for chemical control, you may choose 50% iprodione wettable powder 1000-fold solution, or 50% anilazine wettable powder 500-fold solution, or 2% agricultural antibiotic 120 aqueous solution 200-fold solution, or 50% captan wettable powder 400-fold solution, or 80% mancozeb wettable powder 800-fold solution, or 70% mancozeb wettable powder 600-fold solution. Combined with control of bacterial diseases, you may also choose 47% kasugamycin-copper wettable powder 600—800-fold solution for spraying, applying once every 10-15 days, and applying 1-3 times according to the condition of the cherry tomatoes.