Grapevine Leaf Rust – Assessment of cultivars for resistance or immunity and fungicides useful for control

Abstract

411 genotypes of Vitis spp. were exposed to P. euvitis in the laboratory with four being moderately resistant or better. 91 unidentified Vitis spp. from suburban backyards and native Vitaceae plants (Ampelocissus acetosa and A. frutescens) all tested susceptible or highly susceptible.
Fungicidal control was assessed using 21 different products. 11 were effective in preventing infection and six reduced symptoms as post-infection treatments.
The optimal temperature for spore germination was 22°C. Latent period (of infection) in Vitis spp. leaves was shortest (six days) at 25°C. The optimal temperature for pustule production and sporulation was between 20°C and 21°C whilst six hours of leaf wetness significantly increased symptom development.
A protocol for identification of P. euvitis via PCR-RFLP analysis was successfully adapted and optimised for detection of the fungus at the Berrimah Farm Veterinary Laboratory.
There was no measurable difference between the two types of vine (Vitis spp. and native Ampelocissus spp.) in the microclimate of their canopies during a six-month period.

Summary

Development of a leaf disc testing method