Fusiform Rust Affects Planted Slash Pine

Abstract In order to measure the effect of fusiform rust stem infections on diameter and height growth and survival, plots of approximately 100 trees each were established in a slash pine plantation at 10- by 10-foot spacing. Thirty-two percent of the stems were infected with Cronartium fusiforme. Infected trees grew slightly less than noninfected trees in dbh and total height from age 6 to 16, but differences were nonsignificant. And diameter growth of trees with galls below 5 feet on the stem, an indication of early infection, was not significantly reduced. Eighteen percent of the trees infected at age 6 were dead by age 16, compared to 2 percent of the noninfected trees. Ninety-one percent of all mortality during the study period was attributed to fusiform rust. Based on evaluation at age 16, only 14 percent of the infected trees had potential for early sawtimber production, compared with 75 percent of the noninfected trees.