MySheen

Cotton brown spot

Published: 2024-11-25 Author: mysheen
Last Updated: 2024/11/25, The main symptoms are damage to leaves. Cotyledons infected with primary needle size purplish red spots, and then expanded into brown, purple edges, slightly raised round to irregular disease spots, multiple disease spots fused together in the shape of large disease spots, small black spots scattered in the middle, that is, the conidium of the pathogen. The center of the lesion is easy to break, fall off and perforate, and the leaves fall off seriously. The disease spot of the true leaf is round, yellowish brown, and the edge is purplish red. Pathogen Phyl10stictagossypinaEll.etMart. Call cotton small

The main symptoms are damage to leaves. Cotyledons infected with primary needle size purplish red spots, and then expanded into brown, purple edges, slightly raised round to irregular disease spots, multiple disease spots fused together in the shape of large disease spots, small black spots scattered in the middle, that is, the conidium of the pathogen. The center of the lesion is easy to break, fall off and perforate, and the leaves fall off seriously. The disease spot of the true leaf is round, yellowish brown, and the edge is purplish red.

Pathogen Phyl10stictagossypinaEll.etMart. It is called cotton leaf spot mold and P.malkoffiiBubak. It is called Markov leaf spot mold, and it all belongs to the subphylum of semiknowns. The conidia of the two bacteria were buried in the leaf tissue. The former is spherical yellowish brown, 93.8 μ m high, 85.7 μ m in diameter, 18 μ m in diameter and dark brown. The conidia are oval to oval, with 1 oil drop at each end, 4.8-7.9 μ m long and 2.4-3.8 μ m wide. The conidia of Markov leaf point mold are oval to short cylindrical, with a size of 7.04-9.28 × 3.63-4.5 (μ m), and also have 2 oil spots.

The transmission route and disease condition of the two pathogens overwintered on the residual body with mycelium and conidia. In the following year, a large number of conidia were released from the conidia, which were transmitted by wind and rain and germinated under the condition of high humidity. When the first true leaf of cotton grows, the seedlings grow weakly and are prone to disease in case of low temperature and rainfall.

For control methods, see Cotton Wheel spot.

 
0