New Zealand Journal of Crop and Horticultural Science abstracts
Glasshouse screening for biological control agents of Phytophthora
cactorum on apple (Malus domestica)
B. J. R. ALEXANDER*
School of Biological Sciences
University of Auckland
Private Bag 92 019
Auckland, New Zealand
A. STEWART+
Soil, Plant, and Ecological Sciences Division
P. O. Box 84
Lincoln University
Canterbury, New Zealand
email: Stewarta@lincoln.ac.nz
*Present address: National Plant Pest Reference Laboratory, Ministry of
Agriculture and Forestry, P. O. Box 2095, Auckland, New Zealand.
Abstract In glasshouse trials, 504 fungi and 120 bacteria and
actinomycetes were evaluated for their ability to control root rot of apple
(Malus domestica Borkh.) seedlings caused by Phytophthora
cactorum (Lebert & Cohn) Schroeter. Ten fungi consistently reduced
apple seedling mortality in two screens. In a further seedling screen, disease
caused by P. cactorum was significantly (P < 0.05) lower in
pots treated with Microsphaeropsis sp. F15, Oidiodendron sp.
F762, Paecilomyces sp. F46, Penicillium sp. F120, T.
koningii F176, F929, and F950, and T. harzianum TW.178 (1-30%
incidence) compared with the pathogen control (71% incidence). Five isolates
provided control statistically equivalent (P < 0.05) to that obtained
by the fungicide treatment (metalaxyl + mancozeb). In a separate bacterial
screen, Flavobacterium sp. B219 significantly reduced seedling mortality
(15%) compared with the pathogen control (77%). This bacterium provided 65%
disease control of P. cactorum on MM106 apple rootstocks over a 14-week
period (statistically equivalent to the fungicide) and significantly increased
rootstock height, total fresh weight, and rootstock dry weights. Although 10
fungal treatments also provided a level of disease control (25-73%) on
rootstocks after 14 weeks, only Penicillium sp. F120 (73%) gave
significant control. Across all trials, Flavobacterium sp. B219,
Oidiodendron sp. F762, and T. harzianum TW.178 consistently
provided control that was statistically equivalent to the fungicide
treatment.
Keywords Phytophthora cactorum; biological control;
glasshouse trials; apple; Trichoderma; Oidiodendron;
Flavobacterium
+To whom correspondence should be addressed.
H00044
Received 24 October 2000; accepted 17 May 2001
New Zealand Journal of Crop and Horticultural Science, 2001, Vol. 29:
159-169
0014-0671/01/2903-0159 $7.00 (c) The Royal Society of New Zealand 2001
PDF file of entire paper: medium quality (884K); (scanned from paper original: notes about this process)
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