Browsing by Author "Ngoo, Gisella A."

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Effect of leucaena psyllid attack on leucaena leucocephala seedlings growing under different watering and shading levels
(Sokoine University of Agriculture, 1998) Ngoo, Gisella A.
The effect of leucaena psyllid (Heteropsylla cubana] (Crawford, Homoptera: psyllidae) on the growth of Leucaena leucocephala (Lam.) de Wit seedlings was evaluated in relation to three watering levels (every day, every other day and once a week) and three shading levels (light 10%, moderate 25% and heavy 50%). Three weeks coppices from two months pot grown leucaena seedlings in split plot design was used in the screen house. Generally, fifteen weeks after infestation of the seedlings, infested seedlings were less vigorous, thinner and shorter than the non-infested seedlings. In addition, dry weight production (expressed as oven dry matter) was significantly reduced by the effect of psyllid attack. The effect of attack however, varied with the treatment levels. The biomass loss was 9.7%, 18.6%, 17.2% for seedlings watered every day, after every other day, and once a week respectively. On the other hand shading contributed to respectively 1 5.9%, 4.8%, and 7% loss for seedlings shaded at 10% (light), 25% (moderate), and 50% (heavy). The level of damage, shoot health and nymph abundance although not significantly different among treatments were higher in the water stressed seedlings and in the lightly shaded seedlings than the other treatment levels.