[1] The ICMP had its origin in 1952 as the personal collection of plant pathogenic bacteria and rhizobia of Dr Douglas W. Dye.

The collection has a strong focus on globally sourced plant pathogens, and fungi of New Zealand and the South Pacific, voucher cultures validate the presence of many plant diseases recorded in New Zealand.

The over 22,000 strains are roughly evenly split between bacteria and fungi/yeasts, including 900 type and pathotype cultures.

In 1993, preservation using liquid nitrogen was introduced for fungal and bacterial strains which had been difficult to maintain by vacuum drying; this has since been used for all new accessions.

Printed catalogues of strains were published between 1978 and 1999, but have been replaced by an online database updated daily.