Effect of temperature and moisture content on Egyptian peanut seed-borne fungi

In peanut seeds adjusted to various levels of moisture content (8.5 %, 13,5 %, 17.5 % and 21 % on a dry-weight basis) and stored for six months at 5°, 15°, 28° and 45 °C, seed-borne fungi were monthly identified and counted using the dilution plate method, and the germinability of seeds was tested. The total count of seed-borne fungi (recovered at 28 °C) increased regularly and the germinability declined with the rise moisture content and with the lengthening of the storage period. At 5°, 15° and 28 °C,A. fumigatus was almost the most dominant fungal species followed by several fungi such asAspergillus flavus, A. niger, A. terreus, Penicillium funiculosum, P. notatum, Pyrenochaeta decipians andScopulariopsis brevicaulis. The degree of dominance of each fungal species depended upon the conditions of storage and the length of storage period.A. flavus gained its highest count in seeds adjusted to 13.5 % stored at 15 °C for 1 month.Penicillium predominated at 17.5 % and 21 %, and at 13.5 % and 17.5 % when the seeds were stored for long periods at 5° and 15 °C respectively.The total count of thermophilic fungi (recovered at 45 °C) significantly increased with the rise of moisture content and with the lengthening of the storage period between 1 and 2 months and regularly declined after 4 months.A. fumigatus was so extremely dominant that it was the main component of the total fungal flora. Several fungi truly thermophilic were isolated also. They were,Mucor pusillus, Humicola grisea var.thermoidae, H. insolens, H. lanuginosa (Thermomyces lanuginosus) andSporotrichum thermophile.