Fertilizer induced changes in susceptibility to fusiform rust vary among families of slash and loblolly pine
Phytopathology 67(10): 1280-1284
ISSN/ISBN: 0031-949X Accession: 005456681
Effects of fertilization on susceptibility (percent of seedlings infected) to fusiform rust (caused by Cronarium fusiforme) were observed in 11 artificially inoculated families of slash pine [Pinus elliottii var. elliottii] and 7 families and 1 geographic race of loblolly pine [P. taeda]. Fertilization (N + P + K + Fe) increased the susceptibility of all families, but significant family .times. fertilization interactions were found in both loblolly and slash pine. Seedling susceptibility tests in tree improvement programs should include seedlings both fertilized and not fertilized prior to inoculation. The length of the shoot (the assumed infection court), when seedlings were inoculated 8 wk after emergence, was affected significantly by fertilization, family and their interaction. Shoot length was not correlated with the percentage of seedlings that became infected. Thus, susceptibility in young slash and loblolly pine seedlings is not strongly controlled by the size of the infection court.