Efficacy of Fungicide Applications During and After Anthesis Against Fusarium Head Blight and Deoxynivalenol in Soft Red Winter Wheat

Abstract

Seven field experiments were conducted in Ohio and Illinois between 2011 and 2013 to evaluate postanthesis applications of prothioconazole + tebuconazole and metconazole for Fusarium head blight and deoxynivalenol (DON) control in soft red winter wheat. Treatments consisted of an untreated check and fungicide applications made at early anthesis (A), 2 (A+2), 4 (A+4), 5 (A+5), or 6 (A+6) days after anthesis. Six of the seven experiments were augmented with artificial Fusarium graminearum inoculum, and the other was naturally infected. FHB index (IND), Fusarium damaged kernels (FDK), and DON concentration of grain were quantified. All application timings led to significantly lower mean arcsine-square-root-transformed IND and FDK (arcIND and arcFDK) and log-transformed (logDON) than in the untreated check; however, arcIND, arcFDK, and logDON for the postanthesis applications were generally not significantly different from those for the anthesis applications. Relative to the check, A+2 resulted in the highest percent control for both IND and DON, 69 and 54%, respectively, followed by A+4 (62 and 52%), A+6 (62 and 48%), and A (56 and 50%). A+2 and A+6 significantly reduced IND by 30 and 14%, respectively, relative to the anthesis application. Postanthesis applications did not, however, reduce DON relative to the anthesis application. These results suggest that applications made up to 6 days following anthesis may be just as effective as, and sometimes more effective than, anthesis applications at reducing FHB and DON.

Quantifying the Effects of Fusarium Head Blight on Grain Yield and Test Weight in Soft Red Winter Wheat

“…In brief, the final macroconidia, ascospore, and pycnidiospore concentration was determined using a hemocytometer (Reichert-Bright Line; Hausser Scientific, Horsham, PA), and adjusted to the final concentrations by adding deionized water mixed with Tween 20 (2%). Subplot and sub-subplot treatments were assigned by spray inoculating plots with pycnidiospore suspensions of P. nodorum and a 1:1 mixture of macroconidia and ascospores of F. graminearum, respectively, at concentrations of 0, 0.25, and 0.5 × 10 6 spores ml -1 in 2009; 0, 0.5, and 1 × 10 6 spores ml -1 in 2010 and 2011; and 0, 1, and 2 × 10 6 spores ml -1 in 2012, for the first pathogen; and 0, 1, 3,5,7,9,11,13, and 15 × 10 4 spores/ ml for the second (0, 30, 60, 90, 120, 150, 180, 210, and 240 × 10 3 spores/ml in 2012). Inoculations were done at full flag leaf emergence (Feekes GS 9) for P. nodorum and at anthesis ( SLB severity (percent diseased leaf area) was rated on the flag leaf of 6 to 10 arbitrarily selected clusters of 3 to 5 tillers per subsubplot at the milky ripe growth stage (Feekes 11.1) (14).…”

“…Different planting dates, F. graminearum inoculum densities (as described above), inoculation timings (early, mid-, or late anthesis), levels of infield corn residue (0, 15, and 80% ground cover), fungicide treatments (products or application timing), or a combination of two or more of these factors were used to generate a range of index levels and corresponding grain yields. For the other two experiments, the design was a randomized complete block, with F. graminearum-spray-inoculated plots (as described above) of Hopewell subjected to 10 different fungicide treatments (Prosaro, Headline, and Quadris applied at three growth stages, plus an untreated check) (9), generating a range of IND and yield values. Plot dimensions, planting density, row spacing, data collection, and cropping practices were as described above.…”

Efficacy and Economics of Integrating In-Field and Harvesting Strategies to Manage Fusarium Head Blight of Wheat

“…This is to be expected be cause wheat grain is graded and priced based on quality traits (TW, DON, and FDK) (14,22,24,37), and the total cash income received for a given grain lot is a function of the total YLD and the final grain price after adjusting for quality. How ever, not surprisingly, the profit margin varied considerably among the HRSW in Minnesota, HRWW in North Dakota, and the SRWW in this study, likely reflecting the fact that grain YLD was considerably higher in our SRWW cultivars than in the HRWW and HRSW cultivars; some of the North Dakota experiments had fairly high levels of foliar diseases (over 80% severity in some cases) which, in combination with FHB, could have a greater effect on grain YLD and quality than FHB alone (unpublished); baseline levels of FHB varied among the experiments; and, most importantly, both the North Dakota and Minnesota studies included fungicide treatments (pyraclostrobin [Headline] before jointing [Feekes GS 6] and tebuconazole [Folicur] and a tank mixture of Folicur and prothioconazole [Proline] at anthesis in North Dakota; and Tilt and Folicur before jointing and at anthesis in Minnesota) that are generally less effective against FHB and DON than Prosaro (5,33,35). However, there is a balance between grain YLD and quality in determining net cash income and, ultimately, the EB of a management program.…”

Dissipation and adsorption of isoproturon, tebuconazole, chlorpyrifos and their main transformation products under laboratory and field conditions

“…TCZ [(RS)-1-p-chlorophenyl-4,4-dimethyl-3-(1H-1,2,4-triazol-1-yl methyl)pentan-3-ol] is a systemic triazole fungicide which is used for the control of a range of plant fungal pathogens in different crops including winter cereals (D'Angelo et al, 2014;Keinath, 2015). It is rather persistent in the soil environment with DT 50s ranging from 49 to 610 days (Strickland et al, 2004;EFSA, 2014).…”