Site factors related to fusiform rust incidence in north florida usa slash pine plantations
Hollis, C.A.; Schmidt, R.A.
Forest Science 23(1): 69-77
1977
ISSN/ISBN: 0015-749X Accession: 006423276
The influence of site factors on the incidence of fusiform rust (Cronartium fusiforme) was examined in 6 North Florida [USA] slash pine (Pinus elliottii var. elliottii) plantations which ranged from 1.9-89.8% of the trees infected. Rust was most abundant on the more fertile, well-drained soils where oak (Quercus sp.) and pine grew best and in association with one another. The factor most associated with rust incidence was the amount of inoculum on the oak host. Percent of pines infected increased linearly with .**GRAPHIC**. Other factors associated with percent rust on pines were oak leaf surface area, annual increment of susceptible pine shoot tissue, amount of extractable soil P and internal soil drainage. Favorable ambient temperatures and relative humidity during the basidiospore production and pine infection period occurred frequently at all locations. The periods of maximum inoculum production and host susceptibility for both oak and pine coincided at all locations. Analyses of supplemental data on pine rust incidence and oak volume from 15 counties in North Florida showed a significant positive relation between amount of oak and rust incidence on pine. The high rust hazard sites in North Florida can be identified on the basis of the availability of inoculum, i.e., number of telia, or the potential availability of inoculum, i.e., the amount of susceptible oak tissue.