P-112 - Chemical Control of Rice Sheath Blight: A Meta-Analysis of Fungicide Efficacy Studies in Louisiana

Sheath blight (SB), caused by the fungus Rhizoctonia solani AG1, is a major rice disease in Louisiana and globally. Fungicide application is a common practice for SB control. Fungicide trials on rice SB control have been conducted annually at the LSU AgCenter Rice Research Station since 1973 (n = 233 trials). This study aims to quantify fungicide efficacy through a meta-analytic approach applied to selected fungicide programs. The active ingredients (AIs) azoxystrobin (AZOX; 112, 168, 224 g ai/ha), propiconazole (PROP; 168, 224, 336 g ai/ha), and flutolanil (FLUT; 392, 538, and 1,098 g ai/ha), applied at panicle differentiation plus seven days (PD7), boot (B), and heading (H) growth stages, were selected to represent relevant treatments. A mixed-model multivariate meta-analysis was conducted using yield difference (YD; kg/ha) as the effect size. The variety disease reaction (very susceptible [VS], susceptible [S], and moderately susceptible [MS]) was used as a moderator variable. Overall, AZOX showed a higher YD than PROP and FLUT. The YD ranged from 621 (95% CI: 538, 704) kg/ha for PROP at B and 336 g ai/ha to 1,621 (95% CI: 1,507, 1,735) kg/ha for AZOX at PD7 and 224 g ai/ha. Overall, disease reactions showed inconsistent results, ranging from -340 (95% CI: -1,501, 820) kg/ha for FLUT at PD7 and 392 g ai/ha to 2,466 (95% CI: 1,871, 3,060) kg/ha for AZOX at B and 112 g ai/ha. Future studies will explore other response variables (severity and grain quality), AIs, and moderators. Results of this study will support the decision-making process for SB management.