Septoria Leaf Spot of Lantana from Ecuador: A Potential Biological Control for Bush Lantana in Forests of Hawaii

Resumen

Pathogenicity tests with a Septoria sp. isolated from Lantana camara from Ecuador showed aggressiveness to four L camara selections from Hawaii forests. The initial symptoms of the disease on inoculated leaves were chlorotic spots that appear within 2 weeks, becoming distinctly angular necrotic lesions in 4 weeks, inducing leaf chlorosis and defoliation 6 weeks after inoculation. Inoculum applied at 1 x 10 6 conidia per ml in 2% sucrose-0.5% gelatin solution produced an average of 87 lesions per leaf. Ornamental hybrids of L. camara x L. montevidensis also were susceptible, but these plants had significantly fewer lesions. All selections of L. montevidensis tested were immune. This Septoria sp. from Ecuador is the first pathogen found to be virulent on bush lantana, the most serious ecological threat to Kauai's forest, and its release is presumed to be an effective biocontrol agent for this weed.