Relation of Age of Two Host Fungi to Development of the Mycoparasite Piptocephalis Virginiana

SUMMARY

The age of hyphae of Choanephora cucurbitarum and Phycomyces blakesleeanus influenced the degree and type of host hyphal response in the relationship with Piptocephalis virginiana. Conditions which retarded germination and growth rate of P. blakesleeanus favored the development of P. virginiana. Parasitism of young host hyphae by P. virginiana induced the production of abnormal branching which may be manifested by swollen hyphae, witches' broom, or coiling of the hyphae. Resistance of old host hyphae was due neither to chitin content nor to the thickness of the cell wall.