Leaf Blight of Castor Bean Caused by Phytophthora nicotianae and P. palmivora var palmivora

Kim, Byung Soo; Lim, Yang Sook; Kim, Jeong Hoon

Research in Plant Disease 2004;10(2):100-104.
Published online June 30, 2004.

Phytophthora nicotianae와 P. palmivora var. palmivora에 의한 아주까리 역병

김병수, 임양숙, 김정훈

Leaf Blight of Castor Bean Caused by Phytophthora nicotianae and P. palmivora var palmivora

Byung Soo Kim, Yang Sook Lim, Jeong Hoon Kim

Abstract

Two species of Phytophthora were isolated from a leaf blight disease found on castor bean plants growing at a residential area of Hwanggeum-dong in Daegu city. One species was producing conspicuously papillate, noncaducous, ovoid to obpyriform sporangia, 31.2-58.5 × 25.4-44.1 μm in range with an average of 46.4 ± 6.5 × 35.9 ± 4.7 μm on simple sympodial sporangiophores, was heterothallic with oogonia globose, 22.5-35.0 μm with an average of 30 ± 3.3 μm in diameter, oospores plerotic, 18.8-30.0 μm in range averaging 25.4 ± 2.8 μm, and with antheridia amphigynous. This species was identified as P. nicotianae Breda de Haan. The other species produced papillate, caducous, ovoid to ellipsoid sporangia with pedicel, 21.5-54.6 × 17.6-34.3 μm in range with an average of 41.7 ± 7.1 × 28.4 ± 4.0 μm, and was heterothallic with oogonia globose, 21.3-26.8 μm with an average of 23.0 ± 1.6 μm in diameter, oospores plerotic, 17.5-23.8 μm in range averaging 20.2 ± 1.8 μm, and with antheridia amphigynous. This species was identified as P. palmivora (Butler) Butler. Both species produced chlamydospores. Pathogenicity of the 2 speices was confirmed by foliar inoculation of castor bean seedlings. Both species have been reported to infect castor bean plants in a few foreign countries but it is the first that a disease of castor bean plants caused by either or both of the species was found in Korea.

Key Words: Phytophthora nicotianae, P. palmivora var palmivora, Ricinus communis L