APPEARANCE OF ALTERNARIA GOLDEN SPOT ON CACTUS PEAR IN ITALY

Authors:	G. Granata, A. Sidoti
Keywords:	Cactus pear, disease, fungus, chlorotic spots, scabs
Abstract: Severe cactus pear blight was observed in a growing area on the SW slopes of Mt. Etna. The first symptoms on the cladodes of the infected plants were chlorotic spots around the spines. The spots developed into round and prominent golden yellow scabs, then the center necrotized leaving a yellowish halo. The disease was also seen on the fruits which often presented the same symptoms observed on the pads. Fruits revealing symptoms and those borne on infected pads were underdeveloped and not fit for commercialization. Isolation on PDA using Petri plates carried out on infected tissue from scab margins in diverse periods of the year constantly revealed the presence of a fungal isolate. The morphobiometric characteristics of this fungus classified it as Alternaria alternata (Fries: Fries) von Keissler. Artificial inoculation trials carried out in a controlled climate chamber reproduced the disease. The disease is widespread in Mexico where it is called, "Mancha or Secamiento de la Penca", but has not been reported in Italy. Its diffusion seems related to atmospheric precipitations.
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