Revisiting Fungicide-Based Management Guidelines for Leaf Blotch Diseases in Soft Red Winter Wheat

Abstract

Standard foliar fungicide applications in wheat are usually made between flag leaf emergence (Feekes [FK] 8) and heading (FK10.5) to minimize damage to the flag leaf. However, over the last few years, new fungicide programs such as applications prior to FK8 and split half-rate applications have been implemented, although there are few data pertaining to the efficacy of these programs. Eight experiments were conducted in Illinois, Indiana, Ohio, and Wisconsin from 2010 to 2012 to compare new programs to standard FK8 and FK10 programs in terms of disease control and yield response. The programs evaluated consisted of single full-rate applications of 19% tebuconazole + 19% prothioconazole (Prosaro) or 23.6% pyraclostrobin (Headline) at FK5 (pseudostem strongly erected), FK8, or FK10, or split half rates at FK5 and 8 (FK5+8), plus an untreated check (CK). Leaf blotch (LB) severity and yield data were collected and random effects meta-analytical models fitted to estimate the overall log odds ratio of disease reaching the flag leaf ([Formula: see text]) and mean yield increase ([Formula: see text]) for each fungicide program relative to CK. For all programs, [Formula: see text] was significantly different from zero (P < 0.05). Based on estimated odds ratios (OR = exp[[Formula: see text]]), the two FK8 programs reduced the risk of LB reaching the flag leaf by 55 and 75%, compared with 62 and 69% and 67 and 70% for the two FK10 and FK5+8 programs, respectively, and only 32 and 37% for the two FK5 programs. [Formula: see text] was significantly different from zero (P ≤ 0.003) for all FK8, FK10, and FK5+8 programs, with values of 233 and 245, 175 and 220, and 175 and 187 kg ha−1 for the FK10, FK5+8, and FK8 programs, respectively. Differences in mean yield response between Headline and Prosaro were not statistically significant (P > 0.05). The probability of profitability was estimated for each program for a range of grain prices and fungicide application costs. All FK8, FK10, and FK5+8 programs had more than an 80% chance of resulting in a positive yield response, compared with 63 and 67% for the two FK5 programs. The chance of obtaining a yield increase of 200 kg ha−1, required to offset an application cost of $36 ha−1 at a grain price of $0.18 kg−1, ranged from 44 to 60% for FK8, FK10 and FK5+8 programs compared with 22 and 25% for the two FK5 programs. These findings could be used to help inform fungicide application decisions for LB diseases in soft red winter wheat.

Effect of traditional and intensive management on soft red winter wheat yield and profitability

“…Previous research in Michigan, Kansas, and Wisconsin has shown that the inclusion of foliar fungicide can protect wheat from disease and lead to higher yields, but the resulting economic returns were variable (Jaenisch et al, 2019;Quinn & Steinke, 2019;Roth et al, 2020). Willyerd et al (2015) reported that in Ohio and states in the Midwest, the efficacy and profitability of applying a foliar fungicide to wheat varied with the application rate and timing. Susceptible wheat cultivars also benefit more from a foliar fungicide application compared with resistant cultivars (Cruppe et al, 2021).…”

“…Many farmers in Ohio use foliar fungicide to control diseases throughout the growing season. Farmers commonly apply foliar fungicide at the Feekes 9 growth stage to protect the flag leaf from Septoria leaf blotch, Stagonospora leaf blotch, tan spot, leaf rust, and powdery mildew, or at Feekes 10.5.1 to protect against Fusarium head blight (FHB) and Stagonospora glume blotch (Bhathal et al., 2003; Cook et al., 1999; Jaenisch et al., 2019; Lackermann et al., 2011; Paul et al., 2018; Willyerd et al., 2015). Previous research in Michigan, Kansas, and Wisconsin has shown that the inclusion of foliar fungicide can protect wheat from disease and lead to higher yields, but the resulting economic returns were variable (Jaenisch et al., 2019; Quinn & Steinke, 2019; Roth et al., 2020).…”

“…Willyerd et al. (2015) reported that in Ohio and states in the Midwest, the efficacy and profitability of applying a foliar fungicide to wheat varied with the application rate and timing. Susceptible wheat cultivars also benefit more from a foliar fungicide application compared with resistant cultivars (Cruppe et al., 2021).…”

Disease Management and Estimated Effects on DON (Deoxynivalenol) Contamination in Fusarium Infested Barley

“…Statistical analysis was used to explain relationships between plant disease management and associated yield or yield quality [25][26][27][28], as done previously in wheat and barley [8,[29][30][31][32]. A mixed effects model was made for the relationship between DON production and FHB presence [33,34].…”

The influence of winter wheat leaf diseases on yield and yield components = Ziemas kviešu lapu slimību ietekme uz ražu un tās struktūrelementiem

“…Šķirnes ieņēmībai pret lapu plankumainībām ir būtiska nozīme, taču slimības attīstība šķirnēm dažādos vides apstākļos var atšķirties (Willyeard et al, 2015). Slimības attīstība ir atkarīga no vides apstākļiem konkrētā laukā.…”