Previous View
APSnet Home
Plant Disease Home



Influence of Nitrogen and Potassium on Growth and Bacterial Leaf Blight of Philodendron selloum. R. A. Haygood, Graduate Research Assistant, Department of Plant Pathology, North Carolina State University, Raleigh 27650. D. L. Strider, Professor, Department of Plant Pathology, and P. V. Nelson, Professor, Department of Horticultural Science, North Carolina State University, Raleigh 27650. Plant Dis. 66:728-730. Accepted for publication 16 November 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-728.

Applications of extremely high nitrogen (N) levels significantly (P = 0.05) decreased severity of bacterial leaf blight of Philodendron selloum caused by Erwinia chrysanthemi. However, the high N levels that reduced disease severity of P. selloum grown in 15-cm pots under normal commercial practices resulted in significantly (P = 0.05) reduced plant growth. There was a weak trend whereby increased levels of potassium (K) increased disease severity. In most cases, however, no significant effect (P = 0.05) was found. Applications of high N levels resulted in significantly (P = 0.05) increased tissue N content and significantly (P = 0.05) increased tissue N content and significantly (P = 0.05) decreased tissue K content. Applications of various K levels had no effect on N tissue content, whereas increased K levels caused significantly (P = 0.05) increased K tissue content. Pot size had a direct relationship on N and K fertilizer levels and thus on plant growth. Good quality P. selloum plants were grown in a 3:1:1 medium (pine bark, peat moss, sand) in 15-cm pots with weekly application of N at 350 ppm and K at 704 ppm.