Abstract

Phytophthora leaf blight on 14 tree species is reported for the first time from India and symptoms, disease incidence and damage to the foliage are described. Three species of the genus were identified of which P. citrophthora caused leaf blight on Holoptelea integrifolia and Bauhinia variegate, P. palmivora on Terminalia bellirica and P. nicotianae on Albizia lebbeck, Chukrasia tabularis, C. velutina, Eucalyptus sp., Hovenia dulcis, melia azedarach, Paulownia fortunei, P. tomentosa, Polyalthia longifolia and Toona ciliata. Besides, Phytophthora sp. was found associated with leaf blight of Murraya koenigii. The disease was highly destructive to 3 months old seedlings of M. azedarch which were defoliated to the extent of 40-90% whereas the disease occurred in mild form on 1 yr old seedlings in which less than 20% of the leaves were shed prematurely. The disease was also very much damaging to young seedlings of C. tabularis which were less than 20 cm in height whereas those above 40 cm in height showed marginal defoliation to the tune of 2-10% as against 20-100% in younger seedlings of less than 20 cm in height. The disease occurred in mild form in H. integrifolia in which diseased seedlings were defoliated in a range of 10-60%. On the other hand, the disease in the rest of the tree species was inconsequential and was of academic interest only.

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