Efficacies of Fungicides in Controlling Spot Blotch of Barley

Abstract

Efficacies of 12 fungicides in inhibiting growth of Bipolaris sorokiniana on potato dextrose agar and development of spot blotch symptoms in barley leaf segments inoculated with B. sorokiniana were examined. Efficacies in growth inhibition were high (EC95, 2–40 ppm) for RH-2161, fentin hydroxide, thiram, and carbathiin; intermediate (EC95, 250–500 ppm) for triadimefon, anilazine, captafol, and dodine; and low (EC95, [Formula: see text]) for captan, chlorothalonil, mancozeb, and metiram. In symptom inhibition assays, RH-2161 was extremely effective (EC95, 70 ppm), and anilazine, chlorothalonil, fentin hydroxide, mancozeb, triadimefon, and captafol were highly effective (EC95, 150–300 ppm). Efficacies of foliar applications of six fungicides in controlling spot blotch and promoting yield of barley in the field were also examined. Triadimefon, RH-2161, and fentin hydroxide were applied at 0.25 kg a.i./ha and chlorothalonil, anilazine, and mancozeb at 2 kg a.i. ha−1 at barley growth stages 8, 10.1, and 10.4 (Feekes’ scale). Disease severity was significantly reduced in barley treated with mancozeb, RH-2161, chlorothalonil, fentin hydroxide, triadimefon, and anilazine by 63, 68, 68, 77, 82, and 88%, respectively, compared to checks. All fungicides except chlorothalonil significantly increased 1,000-kernel weights of treated plants in the range of 11–15%. Anilazine, triadimefon, and RH-2161 performed better than other fungicides evaluated in the field.

The pathogenicity and importance of seed-borne infection by Bipolaris sorokiniana on barley in Finland

“…Possibly the dose of 0.3 g a.i./kg seeds was too high, causing toxic effects on young barley seedlings. A number of systemic fungicides effective against B. sorokiniana have been shown to be phytotoxic to barley by Couture and Sutton (1978). The ineffectiveness of benomyl treatment against the fungus agrees with the observations of Richardson (1972).…”

Seedling blight, spot blotch, and common root rot in Quebec and their effect on grain yield in barley

“…However the difference in the mean seedling blight intensity between 1977 and 1978 was negligible. The spot blotch intensity in Quebec was generally low although spot blotch has been an important foliar disease in Ontario (Clark 1979, Couture & Sutton 1978a. This may be attributed, at least in part, to below average rainfall during crop development in 1977, and to the presence of mildew, septoria leaf spot, and net blotch on the foliage in 1978.…”

Response of spring barley to fungicides, plant growth regulators, and supplemental nitrogen

“…Fungicides are usually essential since additional N and PGRs may increase the severity of certain diseases (Dehne 1979, Jenkyn 1976. Fungicides have reduced the severity of foliar diseases of barley {Hordeum vulgare L.) in Canada under standard production methods (Couture & Sutton 1978). However, the significance of fungicide applications in integrated production systems appropriate for barley on Prince Edward Island (P.E.I.)…”