Efficacies of fungicides for control of stem rust of wheat

Abstract

The potential commercial use of fungicides for control of stem rust (Puccinia graminis) of wheat was assessed in field experiments at two sites. Foliar sprays containing either triadimefon or propiconazole were the most effective in reducing disease severity. Chlorothalonil was effective only when applied at an early stage of disease development and where stem rust was not severe in control plots. Dichlone, fenarimol, nuarimol and 2-(thiocyanomethylthio) benzothiazole did not significantly reduce stem rust severity at either site. Even though treatments were applied at an early stage ofthe disease epidemic at one site, disease control on heads, peduncles and sheaths did not exceed 63,36 and 19%, respectively, with any treatment. Increases in grain yield and density, of up to 0.27 t/ha and 8.6 kg/hectolitre, respectively, were barely sufficient to cover the cost of treatment.

Yield loss and fungicide control of stem rust of wheat

“…When long duration of control was required, a single fungicide application at disease onset was equally effective as that applied after a 3-week delay, but was inferior to application at both times. Mayfield (1985) identified the triazole fungicides propiconazole and triadimefon as being moderately effective in control of stem rust of wheat but found that the resultant increases in grain yield and quality were barely sufficient to justify the cost of treatment at that time. In the current study, Folicur (tebuconazole) provided more consistent results in terms of disease control and yield increase than Triad (triadimefon) or Impact (flutriafol).…”

Employing α‐Diazocarbonyl Compound Chemistry in the Assembly of Medicinally Important Aryl(alkyl)thiolactam Scaffold

“…This is a particularly valuable finding in light of the recently reported exploration of monosubstituted 1,2‐ethanedithiols (similar to 9i ) as zinc‐binding groups on natural product largazole analogs for the development of histone deacetylase inhibitors . S–H insertion product 9j clearly belongs to the 2‐alkylthiobenzothiazole scaffold widespread in the bioactive compound domain . We also attempted to involve diazo lactam 7a in the reaction with thiobenzoic acid but no corresponding product was observed.…”

Challenges of Fungicide Control on Wheat Rusts in Kenya

“…This stimulatory effect of fungicide treatments on growth may result in significant yield increases even in the absence of the disease (Wegulo et al, 1998). Fungicide treatments, if applied under high and moderate disease pressure at critical growth stages may reduce large yield losses by suppressing or eliminating stem rust pathogen (Mayfield, 1985). However, greater rust control and greater yield increases may have been possible using higher rates and more applications of fungicides as well as spraying at an earlier stage of the rust epidemic.…”

“…Dill-Mackey et al (2000) induced severe stem rust epidemics in barley and wheat and observed yield losses of 50 to 58%. Mayfield (1985) found a clear relationship between grain yield and disease severity by demonstrating that prevention of a 1% increase in rust severity saved a 2% loss in grain yield. Different fungicides vary in their efficacy to control stem rust.…”

“…tritici (Pretorius et al, 2000) have stimulated interest in the search for effective and economically sustainable chemicals to manage this disease. In recent past the efficacy of various fungicides to control stem rust has been reported (Mayfield, 1985;Rowell, 1985;Loughman et al, 2005 andWanyera et al, 2009). Fungicides can play a major role in integrated management of stem rust disease before new varieties with effective host resistance are released.…”