Field evaluation of Badge SC and Badge X2 for control of bacterial panicle blight in rice

摘要

An experiment was established in a field of League-type soil (pH 5.5, sand 3.2%, silt 32.4%, clay 64.4%, and organic matter 3.8 - 4.8%) at the Texas A&M AgriLife Research and Extension Center, Beaumont, TX. This field had been cropped to rice every two years continuously for many years. The experiment consisted of six treatments (see Table) that were arranged in a randomized complete block design with four replications. Plots consisted of seven 16-ft rows, and spaced 7-in. between rows. The susceptible rice variety Presidio was drill seeded at 80 lb/A on 9 May. Plots received 50 lb N/A of urea fertilizer (46-0-0, N-P-K) on 17 May, 90 lb N/A of urea prior to permanent flood on 17 Jun, and an additional application of 60 lb N/A of urea at panicle differentiation on 28 Jun. For weed control, plots were applied with a mix of herbicides containing Command (0.8 pt/A), Permit (1 oz/A), and Rice Beau (2 qt/A) on 29 May. Permanent flood was established on 17 Jun and plots were irrigated as locally recommended. On 25 Jul, all plots were spray inoculated with Burkholderia glumae at10~8 cfu/ml before the heading stage using a CO_2 pressurized sprayer equipped with a boom of three TeeJet 8002 nozzles spaced 16-in. apart that delivered 20 gal/A at 30 psi. B. glumae was grown in Nutrient's broth medium on a shaker (120 rpm) at room temperature for 2 days. On 26 Jul, plots were sprayed with the products listed in Table below using the same sprayer described above. On 2 and 19 Aug, severity of bacterial panicle blight was rated on the Horsfall-Barratt Scale of 0 to 11, where 0 = 0% affected kernel surface; 1 = 0 to 3%; 2 = 3-6%, 3 = 6-12%, 4 = 12-25%, 5 = 25-50%, 6 =50-75%, 7 = 75-87%, 8 = 87-94%, 9 =94-97%, 10 = 97-100%, and 11 = 100%. Phototoxicity was rated on 19 Aug on a scale of 0 to 5, where 0 = < 10% leaf surface damage, 1 = 10-20%, 2 = 20-40%, 3 = 40-60%, 4 = 60-80%, and 5 = >80%. Plots were harvested at maturity on 9 Sep using a plot combine, and grain yield adjusted to 12% grain moisture. On the bactericide application date, temperature ranged from 76 to 95°F with an average of 84°F, and relative humility ranged from 82 to 93% with no rainfall. Total amount of rainfall in the week preceding the application was 0.86-in. Within 10 days following application, no significant rainfall events occurred. Maximum and minimum temperatures during this period ranged from 89 to 95°F and from 70 to 77°F, respectively, with an average of 83°F.