Fungicide Resistance in <i>Venturia effusa</i>, Cause of Pecan Scab: Current Status and Practical Implications

Pecan scab, caused by Venturia effusa, is the most economically damaging disease of pecan in southeastern United States, and annual epidemics are effectively managed through multiple fungicide applications. The applications can be single greatest operating cost for commercial growers return on that investment impacted resistance. V. effusa produces generations conidia per season, exhibits substantial genetic diversity, overwinters as stromata tree, under immense selection from applied fungicides, all which lead to a high risk developing Since mid-1970s, resistance or reduced sensitivity has been observed isolates methyl benzimidazole carbamates, demethylation inhibitors, quinone outside organotin compounds, guanidines. Over last 10 years, several studies have conducted improved both scab management effusa. aim this review summarize recent developments our understanding context orchards. history, modes action, general use labeled mechanisms stability discussed; conclusions future research priorities also presented.