The Effect of Some Ecological Factors on the Germination of Reproductive Organs and the Growth of Mycelium of Scirrhia pini

1988

S. 93-118

5 Abb., 12 Tab., 25 Lit. Ang.

Unselbständiges Werk

200066083

The fungus Scirrhia pini Funk und Parker is the cause of red needle blight on a number of Pinus species. In Serbia, it has been a pratical problem in Austrian pine (Pinus nigra Arn.) plantations. This fungus occurs most frequently in nature in the form of its condial stage known as Dothistroma pini Hulbary. The paper studies the effects of some environmental factors to the germination of conidia and ascospores. Some physiological properties of different isolates of this fungus have also been studied. The results of the research have shown the following: the optimal temperature for the germination of conidia and ascospores is 22C, minimal 5C, and maximal 30C; The percentage of ascospore germination is lower than the percentage of conidial germination; conidia have got a greater significance in the spreading of the infection, as they are, in addition to their higher germination capacity, being discharged in the longer time interval (from March till November), optimal relative air humidity for the germination of conidia is 100%, and minimal 88% (at this level of air humidity, conidia germinate only after 8 days); conidia have the best germination capacity in mildly acid media (pH 6), but they can germinate between pH 2.5 and 9; optimal temperature for the growth of mycelium is 20C, minimal 3C, and maximal 29C. It has been included that there is the difference between the growth speed of D. pini isolates from Yugoslavia and those from Brasil and Australia, which points to the possibility of the existence of different varieties, i.e. strains of this fungus. The fungus which occurs in Yugoslavia differs from that in Africa, Australia and South America by its constantly greater length of conidia, and because it always forms also its perfect stage on the needles.