The phenology of inoculum production by cronartium quercuum f sp fusiforme on slash pine pinus elliottii var elliottii in north florida and south georgia usa
Chappelka, A.H.IIi; Schmidt, R.A.
Forest Science 29(2): 253-262
ISSN/ISBN: 0015-749X Accession: 006734268
Phenology of aecial sporulation of C. quercuum f. sp. fusiforme was characterized among years (1973-1979) within a population of rust galls (initially 454) in a slash pine plantation planted in 1963 near Gainesville, Florida. Sporulation began earliest on Jan. 30, 1975 and the latest on Feb. 28, 1976, 1977 and 1979 and was negatively correlated with average minimum Jan. temperatures. The earliest and latest dates of termination of sporulation were April 4, 1977 and May 18, 1973. The duration of sporulation for the population of galls ranged from 98 days in 1973 to 35 days in 1977, and was positively related to the number of sporulating galls. The period of abundant sporulation ranged from 64 to 31 days and averaged 44 days. The maximum number of galls to sporulate concurrently decreased yearly from 330 in 1973 to 31 in 1979 and this maximum occurred earliest on Feb. 27, 1975 and latest on March 28, 1979. Geographic variability in aeciospore phenology was studied in three 8- to 12-yr-old slash pine plantations, 2 in north Florida and 1 in south Georgia. Sporulation began at the southernmost latitude, where Jan. temperatures were warmest, 7-10 days prior to that of the 2 more northern locations, and 10-14 days separated the dates when the maximum number of galls sporulated at southern and northern latitudes. Although average Jan. temperatures were colder in 1977 than in 1978, initiation of sporulation occurred later in 1978 at the 2 more northern locations. Galls at the southern most latitude initiated sporulation later in 1977 than 1978. The duration of sporulation for individual galls was 1.4-2.8 wk.