A total of five diseases was recorded during the survey conducted in numerous nurseries and five representative plantations of Paraserianthes falcataria, a fast growing exotic tree species, raised in plantations in Kerala, India. In nurseries only two diseases, viz., web blight caused by Rhizoctonia solani and seedling wilt caused by Fusarium solani were observed. Of these, web blight was recorded commonly and it caused considerable mortality of seedlings. Of the 13 fungicides evaluated in vitro against R. solani, Bavistin [carbendazim] and Terrachlor Super-X [etridiazol + quintozene] gave the maximum inhibition in growth. However, in in vivo only Bavistin (1000 micro g a.i./ml) applied one week before transplanting the seedlings in the infested soil, controlled the disease . Bavistin applied after the appearance of the disease was not very effective. Of the three diseases, namely Botryodiplodia dieback (Botryodiplodia theobromae), Phomopsis shoot dieback (Phomopsis mendax) and bacterial wilt (Pseudomonas solanacearum) recorded in plantations, only Botryodiplodia dieback was the most serious disease prevalent in all the Paraserianthes growing areas in the State. Intensive observations on progress and spread of dieback in a plantation at Kattilappara (Thenmala Forest Division) indicated that the high incidence occurred during the dry-warm period, but during or just after the monsoon it declined as some of the trees recouped partially or completely. The occurrence of the disease was closely associated with fire, debarking by animals and cultivation of tapioca as taungya crop in plantations.