Germination of individual micro sclerotia of verticillium dahliae
Ben-Yephet, Y.; Pinkas, Y.
Phytoparasitica 5(3): 159-166
Viability of individual microsclerotia (MS) of V. dahliae of different sizes (> 37 .mu.m, 37-74 .mu.m, 75-125 .mu.m) was studied throughout repeated transfers in a moist chamber. Germination rate and number of germinating hyphae were positively correlated with the size of the MS. After 13 transfers, some MS of the above size ranges still germinated; some MS germinated until they lost their viability; others did not germinate for a while and then started germinating again. The length of germination time of MS on a synthetic medium was 8 days, with slight differences between MS originating from soil and those from 1 yr old potato stems. Fresh MS from potato stems, however, completed their germination after 36 h. Fewer MS (size > 37 .mu.m) were isolated from soil by the wet-sieving than by the dry-sieving technique. This finding and microscopic observations lend further support to the assumption that MS exist in soil partly in clusters.