Integrated control of target spot and yield of cotton in the Brazilian cerrado biome.

Target spot is a disease that has caused serious damage to cotton crops. This study was carried out to examine if different cotton genotypes, plant heights and fungicide treatments can be used as tools of an integrated control methods of target spot. The experiment was carried out in the 2014/15 crop season, in cerrado biome of Chapadão do Sul - MS, Brazil. It was used a randomized block design in a 2 × 3 × 3 factorial arrangement with four replicates. The factors were two plant heights (1 and 1.5 m), three cultivars (FMT 701, FM 975, and FM 944), and three fungicide treatments (control, FT1, and FT2). Fungicide treatments consisted of sequential applications of different fungicides of the triazole, strobilurin, and carboxamide groups. Cultivar FM 944 showed lower susceptibility to target spot. The shorter plants exhibited lower disease severity. The fungicides pyraclostrobin + fluxapyroxad and trifloxystrobin + prothioconazole reduced the severity of target spot. Cultivar FM 975 had the highest yield. A higher yield was obtained in the upper stratum than in the lower stratum of the plant.

Performance and Profitability of Fungicides for Managing Soybean White Mold: A 10-Year Summary of Cooperative Trials.

White mold, caused by Sclerotinia sclerotiorum, is a yield-limiting disease of soybean in Brazil. Uniform fungicide trials have been conducted annually since 2009. Data from 74 cooperative field trials conducted over a 10-year period were assembled. We selected five fungicides applied two times around flowering: dimoxystrobin plus boscalid (DIMO+BOSC), carbendazim plus procymidone (CARB+PROC), fluazinam (FLUZ), fluopyram (FLUO), and procymidone (PROC). For comparison, thiophanate-methyl (TMET) applied four times was also included as a low-cost treatment. Network models were fitted to the log of white mold incidence (percentages) and log of sclerotia mass data (grams/hectare) and to the nontransformed yield data (kilograms/hectare) for each treatment, including the untreated check. Back-transformation of the meta-analytic estimates indicated that the lowest and highest mean (95% confidence interval [CI]) percent reductions in incidence and sclerotia mass were 54.2 (49.3 to 58.7) and 51.6% (43.7 to 58.3) for TMET and 83.8 (79.1 to 87.5) and 87% (81.9 to 91.6) for CARB+PROC, respectively. The overall mean (95% CI) yield responses ranged from 323 kg/ha (247.4 to 400.3) for TMET to 626 kg/ha (521.7 to 731.7) for DIMO+BOSC, but the variance was significantly reduced by a binary variable (30% threshold) describing disease incidence in the untreated check. On average, an increment of 352 kg/ha was estimated for trials where the incidence was >30% compared with the low-disease scenario. Hence, the probability of breaking even on fungicide costs for the high-disease scenario was >65% for the more effective, but more expensive fungicide (FLUZ) than TMET. For the low-disease scenario, profitability was less likely and depended more on variations in fungicide cost and soybean price.