HortScience (1996) 31, 436-438

Thomas W. Walters, LeRoy A. Ellerbrock, Jan J. van der Heide, James W. Lorbeer and David P. LoParco (1996)
Field and greenhouse procedures to evaluate onions for Botrytis leaf blight resistance
HortScience 31 (3), 436-438
Abstract: Greenhouse and field methods were developed to screen Allium spp. for resistance to botrytis leaf blight (causal agent Botrytis squamosa Walker). In greenhouse evaluations, plants were sprayed with laboratory-grown mycelial fragment inoculum and were incubated at 20C in a chamber with an atomizing fogger. For field inoculations, a portable fog system with windbreaks was erected around experimental plots, and the plants were sprayed with the inoculum on evenings when windless, temperate (18 to 22C) conditions were forecasted. The most effective mycelial fragment inoculum was <21 days old and had ~ 45 to 50 colony-forming units/µl, resulting in an absorbance at 450 nm of 0.2 to 0.3. Rubbing the wax cuticle from leaves was essential to disease development in greenhouse but not in field experiments. Evaluations of eight Allium species, including 55 A. cepa L. accessions, were in agreement with previous studies.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Botrytis squamosa	Onion/garlic/leek (Allium)	U.S.A. (NE)