Seedling diseases averaged 3.1% in yield loss from 1992-2001 (Blasingame & Patel, 2001). This accounts to an estimated average loss of $242 million. Majority of the cotton-growing states surveyed reported Rhizoctonia solani and Pythium spp. as the predominant pathogens followed by Fusarium spp. and Thielaviopsis basicola.

Published data from 1992-2000 were surveyed to determine the efficacy of commercial soil fungicides in their ability to improve early and late seedling emergence and lint yield under non-inoculated and inoculated conditions. Soil-applied fungicides include Rovral 4F, Quadris SC, Ridomil Gold PC, Ridomil Gold EC, Terraclor 2E, Terraclor Super X EC, and Terraclor Super X 18.8G. Treatment costs and economic returns were determined.

Under non-inoculated trials, all fungicides applied at labeled rates improved early and late seedling survival (70-85%) compared to the control (66%). Terraclor Super X 18.8G and Terraclor Super X EC increased lint yield compared to the control and other fungicides. Treatment benefits of $16.88/A and $24.30/A were obtained with Terraclor Super X 18.8G and Terraclor Super X EC, respectively.

Under inoculated trials, soil fungicides improved late seedling survival (42-55%) compared to the control (38%). Terraclor 2E, Terraclor Super X 18.8G and Terraclor Super X EC increased lint yield compared to the control and other fungicides. Treatment benefits of $90.88/A, $99.80/A, and $87.04/A were obtained with Terraclor Super X 18.8G, Terraclor Super X EC, and Terraclor 2E, respectively.

Using these net returns it was calculated that a grower should apply an in-furrow fungicide, assuming conditions favored development of seedling diseases one year in five (Carlson & Main, 1976; Bowen, 1997).