ChileanJAR

Weekly counts of ascospores of Venturia inaequalis (Cke.) Wint. from highly infested leaves collected in Curicó, Chile, were made in the years 19661 to 1969 to determine spring dispersion of the primary inoculum ascospores of apple scab.
Ascospore liberation started the last week of August or early September when the perithecia present on overwintered leaves on the ground had completed its development and the main air temperature was equal ar aboye 8°C.
During the four years and under the conditions of this experiment the results did not follow a normal distribution and the inoculum liberation was every year a continuous process from the beginning to the middle of December. The period of ascospore release ranged from 15 to 17 weeks.
Weekly laboratory testing of leaf samples gave a useful guide to the potential for ascospore release. This method could be used as an aid to apple scab control by allowing accurate estimates to be made for the beginning, maximun and ending of the release period.