The character of gene interaction determining resistance to fungal diseases and gall mite was investigated by topcrossing method in black currant cultivars and forms of different genetic nature. For crossings three maternal varieties (testers) and seven paternal varieties and forms of different resistance to American mildew, Septoria leaf spot and gall mite were employed. Eleven cultivars and forms were assessed that differed in combining ability of resistance to fungal diseases and gall mite. Resistance to American mildew (Sphaerotheca mors-uvae) and Septoria leaf spot (Mycosphaerella ribis) is determined by genes with additive effects. In genetic control for resistance to gall mite (Cecidophyopsis ribis) important are both genes – with additive and non-additive (dominant and epistatic) effects. Black currant form D16/1/-25 was ascertained to be a donor of resistance to American mildew and Septoria leaf spot and cultivar Ben Gairn – a donor of resistance to gall mite.
Daconil 2787 4.17F and 75W (chlorothalonil) controlled leaf spot on photinia (Photinia fraseri) caused by Entomosporium maculatum in 2 tests under commercial nursery conditions. Manzate 200 80W (mancozeb) and Bordeaux mixture significantly reduced incidence and severity of the disease, but Benlate 50W (benomyl), Zyban 75W (thiophanate methyl + mancozeb), and Bayleton 50W (triadimefon) did not satisfactorily control Entomosporium leaf spot on photinia.
This ten-page fact sheet includes a summary of various fungicide spray programs for fungal disease control of early leaf spot, late leaf spot, and white mold/stem rot of peanut in 2012-2016 on-farm trials in Hamilton County. Written by K.W. Wynn, N.S. Dufault, and R.L. Barocco and published by the Plant Pathology Department.http://edis.ifas.ufl.edu/pp334
Genetic control and combining ability of resistance to American mildew, Septoria leaf spot and gall mite in black currant