A protocol for evaluation of the role of disinfectants in limiting pathogens and weed moulds in commercial mushroom production.
In vitro and in vivo evaluations of the effects of three commercial disinfectants on isolates of Trichoderma harzianum Rifai and Cladobotryum dendroides (Bull) W Gams & Hoozemans were combined in the development of methodologies for realistic assessment of disinfectant performance. 'Environ' and 'Purogene' incorporated into agar media at 50 mg AI litre-1 were effective in totally preventing the mycelial growth of T harzianum and C dendroides isolates, whereas with 'Sudol' a concentration of 500 mg AI litre-1 was required. Evaluation of a model in vivo system was combined with observations on the fungicidal effects of disinfectants. Spore suspensions of T harzianum (Th1), T harzianum (Th2) and C dendroides prepared from culture washings with sterilised distilled water were used as contaminating inoculum. Environ, Sudol and Purogene in aqueous solutions at 1000 mg AI litre-1 were sprayed onto these building structure surfaces before or after artificial contamination with spore suspensions. Re-isolation from surfaces was carried out using agar swabs, which were prepared in visking tubing, applied to treated surfaces and incubated at 25 degrees C for 24, 48, 72 or 96 h. Environ and Purogene were more effective than Sudol in limiting the recovery of Trichoderma spp and C dendroides. All three disinfectants applied 12 h after artificial contamination onto wood, concrete or glazed surfaces were able to reduce the recovery of these isolates more effectively than when they were applied 12 h before artificial contamination. Greater persistence of contamination was noted on the rougher surfaces (wood and concrete) than on the smoother glazed surface. It was concluded in this in vivo evaluation that, in many cases, the protection achieved by the physical nature of the smooth glazed tile surfaces was equivalent to that available from the application of disinfectants, thus highlighting the attention needed to the nature of building surfaces in the structures used in the mushroom industry. The artificial contamination and re-isolation techniques allowed significant comparison between disinfectant materials, timings and surface types. In the in vivo experiments using a single standardised test concentration, the relative fungicidal effects of the disinfectants, which varied in the complexity of their active ingredients, were better discriminated than the effects observed in vitro, although the general trend was similar.
Abosriwil
Salem O
SO
Department of Environmental Resource Management, Faculty of Agriculture, University College Dublin, Belfield, Dublin 4, Ireland.
Clancy
Kevin J
KJ
D000363:Agaricales / Q000254:growth & development*; D001203:Ascomycota / Q000187:drug effects* / Q000254:growth & development; D004202:Disinfectants / Q000008:administration & dosage / Q000633:toxicity*; D005659:Fungicides, Industrial / Q000008:administration & dosage / Q000633:toxicity*; D025282:Mycelium / Q000187:drug effects / Q000254:growth & development; D013170:Spores / Q000187:drug effects / Q000254:growth & development; D014242:Trichoderma / Q000187:drug effects* / Q000254:growth & development
D004202:Disinfectants; D005659:Fungicides, Industrial