Root Rot of Carnation Caused by Phytophthora nicotianae (Breda de Haan)
1998
Ruy Kyoung Yul | Jin Kyoung Sik Oversea's Pest Division, National Institute of Agricultural Science and Techology, RDA, Suwon (Korea Republic)
Root rot of carnation caused by isolates of Phytophthora was found at Kongju, 1996. Infected plants appeared symptoms of wilting, brown discoloration on collar area and consequently led to death. The causal pathogen was identified as Phytophthora nicotianae based on morphological, cultural and physiological characteristics. Mycelium was grown to rosette colony pattern on corn meal agar and the growth was 10.2 mm/day on 10% clarified V8 medium at 25degrees. Swelling with radiating hyphae was formed in water and on agar within 7 days. Chlamydospores were abundantly produced on agar within 7 days. Sporangium was prominent papillate, 2~3 apex, 1.2:1 l/b ratio, lateral attachment on sporangiospore and was rarely produced on solid media but produced in water. The shape of sporangium was spherical or ovoid, and the size was 34~73*32~60 (av. 36*66.5) micro m in dimension. The isolates were heterothallic, and mating type A2. Oogonium was spherical, ovoid, 26~36 (av. 36 micro m) in diameter, and antheridium was amphigynious to oogonia. The fungus was able to grow 10~35 degrees, and optimal temperature was 27 degrees.
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