Tropical Grasslands (1989) Volume 23, 105107
THE EFFECT OF THE LEUCAENA PSYLLID ON THE YIELD OF LEUCAENA LEUCOCEPHALA CV. CUNNINGHAM AT FOUR SITES IN THE TROPICS
BRIAN PALMER1, R.A. BRAY2, TATANG M. IBRAHIM3 and M.G. FULLOON1
1CSIRO Division of Tropical Crops and Pastures, Davies Laboratory, PMB, Aitkenvale, Queensland 4814
Leucaena leucocephala cv. Cunningham was grown at 4 sites in the wet tropics, 2 in Indonesia and 2 in Australia. The effect of leucaena psyllids on dry matter yield was examined by comparing the yield from plots sprayed with insecticide and unsprayed plots over a period of approximately 1 year. In Australia, total dry matter production when psyllids were not controlled was reduced to about 45% of that in the sprayed treatment. At 1 site in Indonesia, total yield was reduced by one third while at the other, psyllids did not appear to affect yield. The large amount of damage possible in the first year suggests that psyllids could be a major factor in hindering establishment and reducing yield. Further work is needed to establish the factors responsible for variations in damage levels at different sites.