Temporal Study of the Interaction Between Meloidogyne inconita and Thielaviopsis basicola on Cotton

Meloidogyne incognita (Mi) and Thielaviopsis basicola (Tb) are both important cotton pathogens. In addition, these pathogens may interact synergistically increasing disease losses. The impact of soil texture on each pathogen and their interaction was studied in a microplots using a sandy loam soil (52% sand) and four different artificial soil textures produced by mixing this soil with sand (54%, 63%, 71% and 89% of sand). The five soils were pasteurized and six treatment were used: 1) noninfested, 2) Mi - 4 eggs/cc, 3) Mi - 8 eggs/cc, 4) Tb, 5) Mi - 4 eggs/cc and Tb, and 6) Mi - 8 eggs/cc and Tb. Plots were watered at –10 joules/kg the first 44 days and –30 joules/kg from 44 days to harvest. Plant height, development, weight and yield were reduced as sand content increased, especially at 89% sand. Plant height and growth were reduced early in the season by Tb and damage was less in the soils containing the greatest sand content.  Mi also reduced plant growth and height and delayed fruiting.