A. Root and Seedling Diseases:

1. Rhizoctonia Root Rot (Rhizoctonia solani)
2. Black Root Rot (Thielaviopsis basicaola)
3. Pythium Root Rot (Pythium ultimum)

Root and seedling diseases of cotton are caused by Rhizoctonia, Pythium,Fusarium, Thielaviopsis and by some other species of fungal pathogens. General symptoms for diseases affecting roots include stunting, uneven growth, chlorosis and wilting. These symptoms are apparent when root rots are severe, but they also can be associated with other problems, such as poor fertility or soil factors. The assessment for root and seedling diseases should be done at approximately at the first 2-6 leaf stage stages. The rating scale to be used is a single numerical value where; 0 (approximately no visible symptoms, 1 (approximately up to 10% infection) to 9 (approximately 90% infection or greater). The description of rating scale is as follows

B. Vascular Diseases

1. Verticillium wilt (Verticillium dahlia)
2. Fusarium wilt (Fusarium oxysporum f. sp. vasinfectum)
3. Texas root rot (Phymatotrichum omnivore)

Vascular wilt diseases will be evaluated during the first two evaluations (4-6 nodes and also squaring - full boom). There are two major vascular wilt diseases that occur on cotton: Fusarium wilt and Verticillium wilt. Since the symptoms of these two diseases are similar, they are quite often confused in the field. In Fusarium wilt, the vascular discoloration shows up as a brown to black ring just beneath the bark. In Verticillium wilt the vascular discoloration is wilt more evenly distributed throughout the stem and is lighter in color. Fusarium wilt plants normally show symptoms first at the top of the plants; whereas Verticillium wilt plants show first symptoms at the bottom. The description of rating scale is as follows:

C. Virus Diseases:

Viral diseases differ in their degree and type of symptom expression. Most common viral diseases of cotton include leaf crumple and cotton mosaic. Viral diseases are more prominent on younger (top) leaves. The assessment for viral diseases should be done at approximately at the full bloom growth stage of cotton. For recording reactions, a severity scale of 1 = most resistant or least affected to 9 = most susceptible or most affected is to be used. A commonly used scale equating the numerical value to severity of viral infection is as following:

D. Foliar Diseases

Most common foliage diseases of corn include the Following: Ramularia, Target spot, Stemphilium leaf spot, Alternaria leaf spot, bacterial blight and cotton rust. These foliar diseases are more prominent on older (lower) leaves. The assessment for foliar diseases should be done at approximately the at candle-full bloom growth stages of cotton. The rating scale to be used is a single numerical value where; 0 (approximately no visible symptoms), 1 (approximately up to 10% infection) to 9 (approximately 90% infection or greater). The general description of all foliar disease rating scale is as follows:

E. Boll Rots:

Boll rots occur primarily when cotton is exposed to rainfall and high humidity. Most boll decay is found in the lower half of the plant canopy. The pathogens that can cause boll diseases include: Alternaria macrospora, Xanthomonas malvacearum, Phytophthora capsaci, Fusarium and Diplodia spp. The following scale can be used to assess the boll rot diseases of cotton at approximately 2-3 weeks before harvest.

F. F. Nematodes Diseases:

Root-knot and Reniform nematodes are economically important pests in cotton production. M. incognita or Southern root-knot is prevalent throughout most areas where cotton is grown. Southern root-knot causes damage directly through penetration on the cotton roots leading to a reduction in yield, but in addition, it plays an important role in enabling Fusarium sp. to invade cotton root tissues as well. Reniform nematodes (Rotylenchulus reniformis) are widely distributed pathogens on cotton in tropical and sub-tropical regions. Yield reduction and stunting of plants usually occurs when levels of reniform reach a threshold.

G. Abiotic Disorders/Environmental stressors:

Disorders/diseases induced by abiotic environmental factors can occur in cotton plant from planting to harvest. The cotton crop can be exposed to soil crusting, sun-scald, late frost, wind injury drought, herbicide injury or nutrient deficiency. General symptoms caused by abiotic factors are wide ranged depending on the causal agent. The assessment for abiotic disorders should be done monthly basis throughout the growing season. The rating scale to be used is a single numerical value where; 0 (approximately no visible symptoms, 1 (approximately up to 10% infection) to 9 (approximately 90% infection or greater).