|ISAKEIT, THOMAS - Texas A&M University|
|COLLINS, S. DELROY - Texas A&M University|
|ROONEY, WILLIAM - Texas A&M University|
Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2014
Publication Date: 3/29/2014
Citation: Isakeit, T., Collins, S., Rooney, W.L., Prom, L.K. 2014. Effect of fungicides on sorghum anthracnose and grain mold in Burleson County, Texas, 2013. Plant Disease Management Reports. 8:FC176.
Interpretive Summary: Sorghum anthracnose and grain mold are two important diseases that can significantly reduce yield and seed quality. In this study, three fungicides Proline 480 SC, Headline, and Priaxor were sprayed on two sorghum hybrids BH3822 and BH5566 to determine their effects in controlling these two diseases. Low disease was recorded due to hot and dry weather (1.68 in. rain during June and July) after the pathogen was put onto the plants and during flowering and grain maturation. Averaged over the hybrids, the Headline and Priaxor treatments had less anthracnose infection than the control or the Proline treatment, but none of the fungicide treatments reduced grain mold. There was less anthracnose with BH3822 than with BH5566, but there was no significant interaction of fungicide treatment with the hybrids. There were no significant effects of fungicide treatments on grain yield or test weight.
Technical Abstract: The experiment was conducted at the Texas AgriLife Experiment Station near College Station. The hybrids BH3822 and BH 5566 were planted in replicated plots and treatment arranged in a randomized, blocked factorial design. Each replicate consisted of four, 20 ft rows, with 30-in. row spacing and a plant spacing of 2-3 in. within rows. On 23 May, plots were inoculated with Colletotrichum sublineola by sprinkling a few colonized sorghum seed into the whorls of plants. Fungicides were applied on 7 June (boot growth stage) to the middle two rows with a CO2 backpack sprayer, at 30 psi in a spray volume of 15 gal/A, using TeeJet DG80015VS flat fan tips. Four nozzles, spaced 19 in. apart, treated the two rows. Plants were evaluated for anthracnose on 31 July using a 1-5 rating scale, where 1=no disease and 5=death of plants. To assess grain mold, three panicles were harvested from each replicate on 31 July, threshed, and pooled. Each replicate was assessed for grain mold and weathering using a 1-5 scale, where 1=seed bright with no mold and no discoloration due to weathering to 5=seed was covered entirely with mold, is deteriorated, and looks dead. The center two rows of plots were harvested on 31 July using a John Deere 3300. Data were subjected to an analysis of variance and Fisher's protected LSD was used to separate means. Yields were adjusted to 14% moisture. Hot, dry weather after pathogen inoculation and during flowering and grain maturation minimized disease pressure (1.68 in. rain during June and July). Averaged over the hybrids, the Headline and Priaxor treatments had less (P=0.01) anthracnose than the control or the Proline treatment, but none of the fungicide treatments reduced grain mold. There was less anthracnose with BH3822 than with BH5566, but there was no significant (P=0.05) interaction of fungicide treatment with the hybrids. There were no significant effects of fungicide treatments on grain yield or test weight.