Cultures of accessions grown since 1990 are stored in a walk-in cold room at 4^oC. The duration of storage is an important issue under these conditions, and varies first with genus and in some genera, with certain species. Anecdotal evidence has alerted us to the following trends:

1. Spores of Gigaspora species degrade most rapidly, and our practice is to store cultures of these species for no longer than 8 months before repropagation. Vigilance is especially important with these species, since the spores are the only infective propagules and when they all degrade, the culture is dead.

2. Spores of Scutellospora species degrade less rapidly than those of Gigaspora, with considerable variation among species. Large, dark-spored species degrade much faster than species with smaller pale-colored spores, in part because we see that spores of the former show a much higher frequency of parasitism, especially by saprophytic fungi.

3. Spores of Acaulospora and Entrophospora species in general are the most resistant to degradation and parasitism. As with Scutellospora species, however, the large dark-spored species tend to be more heavily parasitized and as a result, degrade more rapidly with time.

4. Longevity of Glomus species varies considerably with refrigerated storage. There are no discernible consistent patterns as observed for Gigasporaceae (see above). In general, however, dark-spored species, large or small, tend to lose viability faster than small pale or colorless-spored species. But notable exceptions exist. For example, Glomus clarum is a larger pale-spored species, but spores of most isolates degrade almost as rapidly as those of Gigaspora. Parasitism again is an important causal factor, and many Glomus species possess a unique mucilagenous layer (staining pink to red in Melzer's reagent indicating a high carbohydrate content) that often is heavily colonized by saprophytic bacteria and fungi.

Between 1200 and 2000 liters of inocula are stored at 4^oC at any given time. For individual cultures, the volume typically stored ranges from 500 cm³ (deepots) to 1200 cm³ (15-cm diam pots). This includes accession material and trap cultures.

	To store "whole" inocula from mixed or monospecific pot cultures, a thick cutting board is swabbed twice with 70% alcohol. In Brooks Hall, this was done in the hallway outside the greenhouse (with door closed). In our new facilities, this board is on an aluminum table in the prep room.
	Three layers of newsprint is placed on this surface, after which pot contents are chopped with a flame-sterilized hatchet.
	The chopped material is wrapped in two layers of the newsprint, and one end is inserted into a pre-labelled zip-loc bag.
	Once all of the chopped material is transferred to the bag, the newsprint is carefully removed and the bag is sealed. At no time is any of the material in the bag touched by human hands!
	A duplicate label is stapled to the right edge of the bag with light cardboard (file folders work great) -- with the label on both sides. Bags then are arranged alphabetically by label in cold room or incubator. The inoculum in this example is a trap culture from a sugarcane field in Florida, so it was harvested with contents slightly moist to preserve integrity of spores (which will be extracted within 90 days to start monospecific cultures).