Plant Disease (2013) 97, 897-902

M. Twizeyimana, V. McDonald, J.S. Mayorquin, D.H. Wang, F. Na, D.S. Akgül and A. Eskalen (2013)
Effect of fungicide application on the management of avocado branch canker (formerly Dothiorella canker) in California
Plant Disease 97 (7), 897-902
Abstract: Members of the Botryosphaeriaceae family have been associated with branch cankers of avocado trees (Persea americana) in California. Canker infections are initiated by spores entering the host plant through fresh wounds such as pruning wounds. With high-density planting becoming more common in the California avocado industry, more intensive pruning may increase the occurrence of branch canker. The objective of this study was to evaluate the preventive ability of some commercial fungicides belonging to different chemical families against fungal pathogens associated with avocado branch canker. Initially, 12 fungicides were tested in vitro for their effect on the inhibition of mycelial growth of three isolates of Dothiorella iberica and isolates (five per species) of Neofusicoccum australe, N. luteum, N. parvum, and Phomopsis sp. Subsequently, azoxystrobin, fludioxonil, metconazole, and pyraclostrobin, selected because of their low effective concentrations that reduce 50% of mycelial growth (EC₅₀ values), and myclobutanil, selected for its high EC₅₀ value, were tested in two field experiments. Azoxystrobin and fludioxonil were used in a premix with propiconazole and cyprodinil, respectively, in field trials. Significant differences (P < 0.05) were observed among fungicides in field trials. Azoxystrobin + propiconazole had the highest percent inhibition at 52 and 62% (internal lesion length) in trial 1 and trial 2, respectively, although this level of inhibition was not significantly different from that of metconazole. A significant correlation (r = 0.51, P < 0.05) was observed between internal lesion length data in the field experiment and EC₅₀ data from in vitro fungicide screening. Application of azoxystrobin + propiconazole and metconazole can play a key role in protecting Californian avocado against fungi causing avocado branch canker.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Akif Eskalen, Davut Soner Akgül

Research topic(s) for pests/diseases/weeds:
control - general

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Neofusicoccum parvum	Avocado (Persea americana)	U.S.A. (SW)
	Neofusicoccum luteum	Avocado (Persea americana)	U.S.A. (SW)
	Neofusicoccum australe	Avocado (Persea americana)	U.S.A. (SW)
	Dothiorella iberica	Avocado (Persea americana)	U.S.A. (SW)