Influence of foliar-applied fungicides on seed yield of faba bean (Vicia faba L.) in northern New South Wales

Abstract

The effects of 5 foliar-applied fungicides on seed yield of faba bean (Vicia faba) cv. Fiord were studied over 3 years at Tamworth in northern New South Wales. In 2 seasons when the diseases chocolate spot (Botrytis fabae) and rust (Uromyces viciae-fabae) were significant, 5 applications of foliar fungicides after flowering increased yield, by up to 1.6 t/ha in 1990 and nearly 0.9 t/ha in 1992, compared with the unsprayed treatment.Mancozeb, dichlofluanid, and tebuconazole were the most effective fungicides for preventing yield reduction, and vinclozolin and procymidone had little or no effect. Mancozeb and tebuconazole were effective in reducing the severity of both diseases, whereas procymidone was only active against chocolate spot. Differences between the most effective fungicides when applied 5 times or twice (at early and mid flowering) were seldom significant. Seed yields following 2 applications of tebuconazole were significantly higher than from 1 application, but for mancozeb, 2 applications were better than 1 in 1992 only. It was estimated that rust accounted for most of the yield loss in 1990 and 1992, and did so mainly by reducing seed size. Application of mancozeb early and during late flowering provided an effective and economical increase in grain yield in 1990 and 1992.

Yield loss of lentil caused byUromyces viciae-fabae

“…These results are consistent with those of Marcellos et al (1995), Rashid & Bernier (1991) and Yeoman et al (1987) who reported that yield loss in faba bean infected with U. viciae-fabae was due mainly to reduced seed mass. In addition, a foliar disease such as brown spot (Septoria glycines) has been shown to cause yield loss in soybean in a similar manner (Hartman et al, 1987), and Shtienberg (1990) reported that leaf rust substantially decreases final seed mass in wheat.…”

“…Should chemical control of lentil rust be an economically viable control option, the most effective time to spray is between flowering and seed filling. This is consistent with a study on faba bean where mancozeb applications at early and late flowering controlled U. viciae-fabae and increased grain yield (Marcellos et al, 1995).…”

“…Treatments were arranged in a randomized complete block design with six replications. The fungicide Folicur ® 250 EW (tebuconazole) (Marcellos et al, 1995) was applied at a rate of 500 ml ha -1 plus a wetting-spreading agent (Foliwett ® 900, 10 ml 100 l -1 H 2 O). The unsprayed check served as a control treatment.…”

Faba bean breeding for resistance against biotic stresses: Towards application of marker technology

“…is the causal agent of faba bean rust, a disease with worldwide distribution that can cause up to 70% yield loss in early infections. Although chemical control of this disease has been reported (Williams, 1978;Gaunt, 1983;Yeoman et al, 1987;Marcellos et al, 1995;, it is obvious that other cost-effective and environmentally friendly alternatives to the extensive use of fungicides should be provided. On the other hand, the use of biological control (Gaunt, 1983) or systemic induced resistance (Murray & Walters, 1992;Rojas et al, 2004) and cross protection (Yarwood, 1956) is not yet viable at the commercial level (Stoddard & Herath, 2001).…”

Identification of RAPD markers linked to the Uvf-1 gene conferring hypersensitive resistance against rust (Uromyces viciae-fabae) in Vicia faba L.

“…Several methods for rust control have been developed, including biological control (Gaunt 1983), systemic induced resistance (Murray and Walters 1992;Sillero 1999) and cross protection (Yarwood 1956), but these have proved to be inapplicable at the commercial level (Stoddard and Herath 2001). Chemical control of the disease has been reported (Williams 1978;Gaunt 1983;Yeoman et al 1987;Marcellos et al 1995;, but the extensive use of fungicides is not desirable in sustainable production systems of grain legumes where the most efficient use of chemicals is pursued. For an increased efficiency in their use, chemicals should be combined with partial disease resistance.…”