PHYTOPATHOLOGICAL NOTE NEW DISEASES OF ORNAMENTALS IN EGYPT: IV: CUT FLOWER PLANT: ASTER

Astor. family Astereracoao. consists of 500 species of herbaceous perennials and a very few annuals ⁽³⁾. The perennials have been known as a long-lasting cut flower for many years. Therefore. some of the high quality varieties were recently introduced to Egypt during the last five years (1998-2002) for cultivation in the open field and/or greenhouses in order to export their flower yields. Three fungal diseases are recorded during the survey performed from 1999 to 2002 in Astor spp. cultivations in Cairo. Alexandria. Giza, Oalubyia and Sharkyia Govom­orates. The most prevalent disease problem is powdery mildew (Erysipho cichoracear­urn), which affects foliage and stems ^{(1. 2. 4}' ⁵' ^{7 8)}. Infection occurs in humid condi­tions. but its spread is favoured by dry atmosphere. It firstly appears as white to gray patches of the fungal growth on the lower leaves of the plant, then progresses to cov­er the entire plant foliage (Fig. 1). General distortion of leaf tissues is the result of in­fection: yellowing may also result. In severe cases, growth of shoots may cease and flower develpment may be aborted. Root and basal stem rot caused by three species of Fusanum (F. eguisett F. solani, F. oxysporum), Pythium sp. and Rhizoctonia solani C^{I4 a 8)}. affects seedlings of aster plants (Fig. 2) causing stunting, yellowing, withering. brown to black discoloration to basal stems and/or partial or complete death. Flower blight (Alternaria alternate) causes partial or complete dry rot to flowers which, howev­er, turn to brown or black color. Based on symptomatology, morphological and biological characteristics and pa­thogenicity tests, the causal agents of these diseases were identified for the first time in Egypt.