Bunchy and malformed top of papaya cv. Eksotika caused by Thrips parvispinus and Cladosporium oxysporum

W. H. Lim

Abstract

The cause of bunchy and malformed top of papaya cv. Eksotika. was investigated. Inoculation studies showed that Thrips parvispinus through their feeding (scraping and sucking) on voung developing leaves provided the infection site (the damaged tissues) for invasion bv the normally saprophytic fungus. Cladosporium oxvsporum. The damaged leaf  on expansion. exhibited the typical malformed symptoms, characterized by shattered and distorted leaf spots/streaks and shot-holes on the lamina. Thrips, in the absence of C. oxysporum only caused slight mottling or streaking of the leaf without malformation, while C. oxysporum without thrips could not cause infection. A field trial on chcmical control showed that weekly fungicidal sprays of benomyl (0.05% b.a) alternated with mancozeb ( 0.1% a.i. ) provided very good control of bunchy/malformed top while only limited control was obtained with insecticidals prays ( decamethrin 0 .0031% a.i. and methamidophos 0.1 % a i. ).

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