Submitted to: Phytopathology
Publication Type: Proceedings
Publication Acceptance Date: 6/25/2005
Publication Date: 8/1/2005
Citation: Rayamajhi, M.B., Van, T.K., Center, T.D. 2005. Impact of puccinia psidii on the performance of invasive tree melaleuca quinquenervia in florida. Phytopathology. 95(6):S87. Interpretive Summary: Melaleuca rust fungus attacks and causes extensive damage to new foliage and soft stems of melaleuca in Florida. We evaluated the impact of this rust on melaleuca saplings and coppices. Melaleuca rust defoliated, deformed, and killed branch-tips of saplings and sprouts from coppices of melaleuca trees. Rust infected plants tend to be shorter and bushier than healthy plants. Additionally, it affected levels of soluble sugars, starch, and nitrogen in leaf tissues and their distribution to other parts of the plant.
Technical Abstract: Puccinia psidii is a rust fungus of neotropical origin that attacks and causes extensive damage to new foliage and soft stems of the invasive tree Melaleuca quinquenervia (melaleuca) in Florida. Herein, we evaluated the impact of this rust on melaleuca saplings and coppices. Puccinia psidii defoliated, deformed, and killed branch-tips of saplings and sprouts from coppices of melaleuca. Rust infected plants were significantly shorter and bushier than healthy plants. Additionally, P. psidii affected the nutrient status of melaleuca leaf tissues. Total non-structural (soluble and non-soluble) carbohydrates in dry samples were significantly lower (P=0.05) in rust-infected (1.53 mg/g) than in healthy foliage (2.06 mg/g) of the same age. Starch content, however, was higher in rust-infected (0.43 mg/g) than in healthy (0.32 mg/g) leaves. Similarly, C/N ratios in melaleuca leaves increased with increased level of rust-pustule coverage on the leaves.