wildfire(redirected from Grass fire)
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an infectious disease of tobacco and Indian tobacco caused by the bacterium Pseudomonas tabacum. Wildfire is characterized by the appearance of numerous pale yellow chlorotic spots, reaching 2 cm in diameter, on the leaves and, sometimes, on the sepals and pods. The diseased areas desiccate in dry weather and rot in humid weather, which often leads to the perforation of the leaves. The causative agent of wildfire enters the plant through the stomata and damaged tissues. The bacterium is preserved in dust that has settled in drying sheds or clinged to seeds and to greenhouse stock; it is also preserved in the unrotted remains of a harvest. Wildfire decreases harvests by 40 to 50 percent. Prices for tobacco leaves drop by 80 percent when the leaves are diseased.
Control measures include using liquid disinfectants on seeds, disinfecting greenhouse stock, spraying seedlings with Bordeaux mixture during the phase of two true leaflets, and growing resistant varieties. The application of potash fertilizers and autumn plowing are also recommended.
REFERENCESGrushevoi, S. E. Bolezni tabaka i sistema meropriiatii po bor’be s nimi. Moscow, 1950.
Leonov, I. P., A. G. Petrenko, and G. M. Psarev. Posobie dlia tabakovodov. Moscow, 1968.
S. E. GRUSHEVOI