Effects of Seasonal Fungicide Sprays on Perithecium Formation and Ascospore Production in Venturia Inaequalis

Abstract

Ross, R. G. eNo NEwnrnv, R. J. 19 Mclntosh (1969) and Burchill (1972) have receiving seasonal sprays of these funshown that fungicides applied to the foliage gicides and the fungicide triforine. Byrde et of apple (Malis pumila-Mill.) trees after al. (1973) reported that apple scab infection harvest suppressed the formation of was less on trees that had been sprayed with perithecia of ine appte scab fungus, Ze,?-benomyl the previous season and suggested iuria inaequclts (Cli.) Wint. However,

Full-season and post-harvest applications of sterol-inhibiting fungicides to reduce ascospore formation in Venturia inaequalis

“…It has been recognized for many years (Jehle and Cory 1924;Keitt and Palmiter 1937) that post-harvest sprays with eradicative activity could inhibit pseudothecial differentiation and ascospore formation, thereby allowing growers to be more successful with their early season protection programs (Conner and Heuberger 1968;Gadoury and MacHardy 1986). Phenyl mercuric chloride (Burchill and Hutton 1965) and benzimidazole fungicides (Ross 1973;Ross and Newbery 1975) hâve been used in some post-harvest programs, although problems with mammalian toxicity and fungicide résistance, respectively, hâve limited their usefulness (Schwabe 1982). The objective of our study was to examine the relative efficacy of several SI fungicides, used either in full-season programs or as post-harvest applications, to reduce ascosporic inoculum.…”

Epidemiology of Mycosphaerella populorum Thompson on the foliage and stems of Populus species

“…Particularly, over 80 years of intensive study on the apple scab pathogen, Venturia inaequalis (Cke.) Wint., directly resulted in a number of predictive and forecasting programs (Jones, 1978), more efficacious use of fungicides (Gilpatrik, 1978), and alternative methods of managing primary inoculum (Ross and Newberry, 1975). Extensive research on ascospore production and release and on conditions necessary for infection by inaequalis also provide an excellent model for similar studies on populorum.…”

“…A relationship between pseudothecial initiation and foliar lesions apparent during the growing season has permitted forecasting ascospore levels in commercial apple orchards (Lewis, 1980;Gadoury and MacHardy, 1986). Study of pseudothecial ontogeny has also allowed more precise evaluation of the effect of fungicides that inhibit pseudothecial initiation and development (Ross and Newberry, 1975). Hirst and Stedman, 1962;Brook, 1969b).…”