Reduction in Spread of Mycoplasma-like Organism-Associated Lethal Decline of the Palm, Veitchia merrilli, by Use of Insecticides12

Abstract

An experiment was conducted in southern Florida in an area where Manila palms, Veitchia merrillii (Becc.) H. E. Moore, were infected with mycoplasmalike organism-associated lethal decline. Manila palms were given foliar applications of insecticides (diazinon AG 500 at 13 ml/10 liters and dimethoate 400 at 26.4 ml/10 liters) biweekly for 15 months. Myndus crudus (Van Duzee) (Homoptera: Cixiidae) was the most abundant auchenorrhynchous insect sampled from the leaves of Manila palms. There were fewer M. crudus in samples from palms treated with diazinon than in samples from untreated palms (P <0.05). The apparent rate of spread of the disease declined significantly in the diazinon and dimethoate-treated plots but not in the untreated plots (P <0.05). The results suggest that a leaf-feeding insect, possibly M. crudus , is the vector of the disease agents.