M.T. AUSTIN¹, M.J. WILLIAMS², A.C. HAMMOND², J.H. FRANK³ and C.G. CHAMBLISS³

¹Hawaiian Sugar Planters' Association, Aiea, Hawaii
²USDA, ARS, Subtropical Agricultural Research Station, Brooksville, Florida
³University of Florida, Gainesville, Florida

Abstract

To identify possible sources of psyllid resistance and determine the effect of psyllid damage on biomass yield of various Leucaena spp. and hybrids in subtropical Florida, a 3-year trial was conducted at Brooksville, Florida. Leucaena spp. tested were L. leucocephala K8, K584, and K636, L. pallida K376 and L. esculenta K948. Three F₂ hybrids in the trial were L. pallida × L. diversifolia KX1, L. pallida × L. leucocephala KX2 and L. diversifolia × L. leucocephala KX3. Leucaena esculenta and L. pallida consistently displayed the lowest psyllid damage (P < 0.01), with L. esculenta being essentially free from psyllids and damage.Leucaena leucocephala selections had the highest damage ratings (P < 0.001) in 19 of 20 high psyllid-infestation events over the 3 years, while the F₂ hybrids had intermediate levels of damage. Adult psyllid populations were positively correlated with plant damage (P < 0.05) in 18 of 20 high psyllid-infestation periods, while nymph populations were positively correlated with damage (P < 0.001) at all 20 observations. Psyllid damage was positively correlated with edible dry matter (DM) and total DM for only 2 of 11 harvests. The lack of correlation between psyllid damage and biomass yield suggests that psyllid-susceptible L. leucocephala selections can be grown in subtropical Florida.