Australasian Plant Pathology (1999) 28, 139-148
R.J. Southwell, J.F. Brown and Sara M. Welsby (1999)
Microbial interactions on the phylloplane of wheat and barley after applications of mancozeb and triadimefon
Australasian Plant Pathology 28 (2), 139-148
Abstract: In field experiments mancozeb significantly reduced fungal populations on wheat and barley leaves whereas triadimefon had only a minor effect. Bacterial populations were not directly affected by either fungicide nor did bacteria colonise and populate the vacant niche resulting from fungicide application. The effect of the two fungicides on phylloplane fungi was closely related to their effect on the growth rates of these fungi in vitro. Microbial populations on leaf surfaces were dominated by the pink yeast Rhodotorula glutinis, the filamentous fungus Cladosporium cladosporioides and the bacterium Pseudomonas fluorescens. A single application of mancozeb caused significant reductions in the fungal populations in field trials in 1982 and 1983. Three applications of mancozeb prevented recolonisation during the experimental period of 24 days. The duration of this effect was greater in 1983 than in 1982. Disturbed habitats were recolonised by the same species of fungi that were initially present on the phylloplane In contrast, triadimefon did not reduce fungal populations on wheat and barley in trials in 1982 and caused only a small reduction in fungal populations after a second and a third application in 1983. The effects of the two fungicides on the dominant phylloplane fungi appeared to be directly related to the sensitivity of these fungi to the fungicides. The effects of triadimefon and mancozeb on the biodiversity of fungi and bacteria on the phylloplane over time were minimal.
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Research topic(s) for pests/diseases/weeds:
control - general
environment - cropping system/rotation
Research topic(s) for beneficials or antagonists:
resistance to pesticides
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Rhodotorula glutinis (antagonist) | ||||
| Pseudomonas fluorescens (antagonist) | ||||
| Cladosporium cladosporioides (antagonist) |
