Nitrogen and establishment of a beetle for biological control of the floating weed Salvinia in Papua New Guinea.

Published online
11 Jun 1985
Content type
Journal article
Journal title
Journal of Applied Ecology

Room, P. M. & Thomas, P. A.

Publication language
Papua New Guinea


A population of 570 adult beetles (Cyrtobagous sp.) released onto plants of Salvinia molesta in field cages declined to 40 adults over 7 months, and increased to 3000 adults with weekly application of urea. On release from cages and in unsprayed controls, populations of the insect increased exponentially. It is suggested that there is a critical population density. Practical implications for biological control of weeds and management of crop pests are discussed.

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