Isolation and Identification of Fungi Associated with Leaf Spot Disease of Some Ornamental Plants in Misan, Iraq

Abstract

The infection rate (%) of leaf spot disease on some ornamental plants grown in five nurseries from different locations in Misan province, Iraq named Bougainvillea spectabilis, Catharanthus roseus, Kalanchoe blossfeldiana, Lantana camara and Rosa damascene was evaluated. Kalanchoe blossfeldiana had the highest infection rate (79.4%), whereas Lantana camara had the lowest infection rate (57.28%). 30 fungal species belonging to 13 genera were isolated and identified. Alternaria alternata was isolated from Bougainvillea spectabilis, Kalanchoe blossfeldiana and Rosa damascene with relatively high frequency and occurrence rates of 6.1 and 12.5%, respectively, whereas Scopulariopsis brevicaulis isolated from Kalanchoe blossfeldiana and Rosa damascene had the lowest frequency and occurrence rate of 1.0 and 0.7%, respectively. Ten fungal species belonging to six genera were isolated and identified from the nursery soils in which these plants were grown, and the fungus Alternaria alternata recorded the highest frequency and occurrence rates of 12.8 and 20%, respectively, followed by Rhizoctonia solani with frequency and occurrence rates of 11.4 and 17.7%, respectively. However, Rhizopus stolonifer had the lowest frequency and occurrence rates of 2.8 and 4.4%, respectively. In addition, seven species of fungi belonging to five genera were isolated and identified from the air of the same nurseries. Aspergillus niger recorded the highest frequency and occurrence rates of 16.6 and 32%, respectively, followed by Alternaria alternata with frequency and occurrence percentages of 12.5 and 24%, respectively, whereas Mucor racemosus recorded the lowest frequency and occurrence rates of 4.1 and 8%, respectively.

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Keywords:

Alternaria alternata, leaf spot disease, ornamental plants, fungi, frequency, occurrence.