01775nas a2200133   4500008004100000245009400041210006900135300001600204490000700220520127400227100001901501700001501520856010601535       1979                        eng d00aPhytophthora cinnamomi in Hawaiian forest soils: seasonal variations in population levels0 aPhytophthora cinnamomi in Hawaiian forest soils seasonal variati  a1268–12720 v693 a<p>Soils from three ohia forest sites with trees showing varying degrees of decline, and from adjacent healthy and declining sites, were sampled biweekly for population levels of <em>Phytophthora cinnamomi</em> over an 8- to 13-mo period. Population levels varied considerably among sites and within the same site throughout the course of the study. At the three sites, the fungus generally was undetectable or its population levels were lowest in the winter months when minimum soil temperatures were near 10 C and then they increased as soil temperatures increased. Population levels decreased after extended periods of heavy rain and measurements at six of the eight monthly sampling times were significantly higher at the decline site than at the adjacent healthy site. Significant correlations between <em>P. cinnamomi</em> population levels and maximum soil temperature, minimum soil temperature, and rainfall were found at some sites but not at others. Soil matric potentials at all sites ranged from 0 to –30 mb and were seldom less than –25 mb. High water holding capacity of the soils combined with rainfall averages ranging 2,984–3,489 mm/yr apparently were favorable for sporangium formation. Zoospores were prevalent at certain times of the year.</p>1 aKliejunas, J T1 aNagata, JT  uhttp://www.apsnet.org/publications/phytopathology/backissues/Documents/1979Abstracts/Phyto69_1268.htm