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Survival of primary conidia and capilliconidia of isolate 3186 of Erynia radicans was compared at 50, 90, and 100% relative humidity (RH), 20°, 25°, and 30°C, and incubation periods of 24, 48, and 72 hr, in darkness. The capilliconidia invariably survived better than the primary conidia, especially at the unsaturated atmospheres, as expressed in subsequent germination on agar medium. At 50% RH and 20°C, 19% of capilliconidia still survived after 5 weeks, compared to almost none of the primary conidia after only 1 week. Addition of light (white, fluorescent) to a low RH treatment significantly reduced capilliconidial survival. The capilliconidia of three additional isolates of E. radicans, and of an isolate each of Erynia phalloides and Neozygites fresenii, also survived at 50% RH and 20°C in darkness for a week (32–76.3% germination), but almost none of their primary conidia survived (max 0.3% germination). For Erynia phytonomi, lower temperatures, 10° and 16°C, were required for survival of 9 and 16% of the capilliconidia at 50% RH in darkness for a week, while almost none of their primary conidia survived this treatment. The importance of this phenomenon to capilliconidia-forming fungi in their natural environment is discussed. |
