Kr. Everett et Hf. Neilson, EVALUATION OF FUNGICIDES FOR CONTROL OF ALTERNARIA LEAF-SPOT OF PSEUDOPANAX, New Zealand journal of crop and horticultural science, 24(3), 1996, pp. 267-272
Alternaria tenuissima causes a leafspot disorder of Pseudopanax 'Gold
Splash', a New Zealand native shrub with export potential. A range of
fungicides viz., bitertanol, captafol, chlorothalonil, dichlofluanid,
iprodione, mancozeb, prochloraz, procymidone, propineb, and vinclozoli
n were tested for efficacy against the pathogen. Three techniques were
used based on growth on: (1) fungicide amended media; (2) leaf disc;
and (3) intact plants. The efficacy of fungicides in agar was not dire
ctly related to their effectiveness on leaf discs or on intact plants.
In contrast, all fungicides effective on leaf discs were also effecti
ve on intact plants. The leaf disc technique showed that bitertanol, c
hlorothalonil, iprodione, prochloraz, and vinclozolin became less effe
ctive 4 weeks following application. In contrast, captafol, dichloflua
nid, and propineb were effective inhibitors throughout the 4 weeks tes
ted by the leaf disc technique. On pot plants in a greenhouse, mancoze
b was the most effective protectant followed by propineb, prochloraz,
dichlofluanid, and captafol.