Storage fungi of onion and their control

Botrytis allii Munn caused total onion damages of 15—20 % during storage in 1975—1979, and was present on 80—90 % of the spoilt onions. The proportion of damage caused by Fusarium oxysporum Schl. was 0—5 % and was present in 0—10 % of the spoilt onions. The early weight losses during storage of the onions were mostly due to storage pathogens which spread via the onion sets used as propagation material. This can be prevented very effectively by soaking the sets in benomyl solution before planting out. The unusually high fungus content of the sets resulted in a reduced yield. Spraying with fungicide early on in the growing season and applying different amounts of nitrogen fertilizer had no significant effect on the number of storage pathogens. A low stroge temperature did not inhibit the development of storage pathogens, it merely slowed it down.

Aerometric study of viable fungus spores in an animal care facility

Studies of airborn fungi were undertaken to evaluate exposure risks for laboratory animals and human handlers which might lead to allergic or invasive disease. Although sporadically high fungus levels were encountered, counts of viable fungus particles were in general low. Recoveries on malt extract agar significantly exceeded those on Sabouraud dextrose agar. The taxa most frequently and abundantly recovered were Penicillium species. Data analyses suggest that 'clean' bedding material may be the principal source of these spores, that cleaning temporarily increases spore levels, and that outdoor airborne fungi contributed little to the indoor air spora identified. Aspergillus fumigatus was infrequently encounted in our samples, and dermatophytes were not recovered.

MICROBIOLOGICAL STUDIES OF AIR MASSES OVER MONTREAL DURING 1950 AND 1951

The numbers of bacteria and fungi in air masses over Montreal, Canada, were determined by sampling at the top of the Sun Life Building, 400 ft. above ground level, from September 1950 to December 1951. During 113 days of sampling, 978 exposures were made with agar plates in the General Electric Bacterial Air Sampler and the Bourdillon Slit Sampler. Eighty-seven exposures for fungus spores were made with silicone coated slides in the Slit Sampler. Most of the air encountered was continental polar either moving direct to Montreal, found on 38 days, or modified by moving over agricultural land, sampled on 51 days. Maritime polar air from the Atlantic was encountered on 21 days, and from the Pacific on one day. Maritime tropic air from the Gulf of Mexico was encountered twice. The seasonal variation of bacteria and fungi in all air masses showed low counts in January, February, and March. Higher bacterial counts were obtained from early April into July and from early September into November, covering a range from 3.0 to 55.0 per cu. ft. Lower counts were found during late July and August. The high fungus counts extended from May into November and covered a range from 5.0 to 56.3 per cu. ft. Both continental polar and maritime polar air that moved over considerable cultivated land showed generally higher counts than where these air masses moved directly to Montreal.