Your Cotton production could be at risk of harmful fungi …
Cotton Seedling Disease
Many pathogenic organisms are involved in cotton seedling disease. These soil-borne fungi are widespread in soil and cause seedling and root diseases in many plants including cotton.
Soil fungus with highly active saprophyte stage, survives in soil in the absence of cotton for indefinite periods of time. Any practice or weather that delays seed germination or seedling growth increases the probability of developing seedling disease. Temperature is frequently the most important factor influencing the rate of seed germination, soil temperature is extremely variable and may be marginal for growth and seedling emergence during the planting period.
Seedling disease is more severe and widespread when fungal inoculum increases because of repeated planting in the same field. Several species of Pythium have been described as causing seedling disease.
Black Root Rot
Black root rot of cotton: the incidence of the disease at lower elevations has increased corresponding with an increase in acreage of Pima cotton. Causes of black cortical decay of the tap root, delays seedling development and may even cause seedling death. Although infected plants can recover due to cortical regeneration and secondary root growth. All varieties of upland cotton are equally susceptible to black root rot.
Infected roots are black in appearance because of the number of black spores that are on infected tissue. These spores survive in the soil and germinate and initiate root infection during early root elongation. Planting into cold soil is the primary cause of disease.
It occurs only in the low-organic matter soil. It causes a root rot in over 2,300 species of dicotyledonous plants, Symptoms generally appear during flowering and boll set. Appearance of roots remain healthy, in contrast to Phymatotrichum root rot where the entire tap root is destroyed.
Leaf diseases
During summer rains, the spore stage on grama grass germinates to produce airborne spores which are carried up to eight miles and cause initial infections. All new infections are dependent upon spore showers from grama grass; the spores produced on cotton can only infect grama grass. The most common symptom is the appearance of yellow to orange spots on the upper and lower leaf surfaces. The spots become brown with age. Spots appear on any of the above ground parts including bracts and bolls.
