Unusually high lethal yellowing disease incidence in Malayan Yellow Dwarf coconut palms on localised sites in Jamaica and Florida. - (:unkn) unknown (1987 : [Publisher not identified])
The 'Malayan Dwarf' cultivar of the coconut palm, Cocos nucifera L., has been recommended of planting in Florida and areas of the Caribbean affected by lethal yellowing (LY) disease due to its high resistance to this disease. It was discovered that at 3 sites each in Florida and Jamaica there were abnormally high losses of 'Malayan Dwarf' palms due to a disease with symptoms similar to, but sometimes atypical of LY. Observations were made at these and other sites to diagnose the disease, determine its distribution, and to identify factors influencing the relatively high susceptibility of 'Malayan Dwarf' to this disease. Mycoplasma like organisms were found in tissue samples from 'Malayan Dwarf' palm with symptoms typical and atypical of LY, and diseased palms responded to oxytetracycline treatments, thus, the authors concluded that the disease was LY. Losses of palms at the 3 localities in Florida ranged from 42.9 percent to 100 percent, and at the 3 localities in Jamaica from 14 to 40 percent. The problem is so far restricted to these and possibly a few other sites. The possibility that the 'Malayan Dwarf' palms were affected by new strain of the LY agent in discussed. Although yhe 'Malayan Dwarf' at the affected sites may have been genetically impure and lacking in genes for resistance, evidence is presented that the high rate of susceptibility observed was more likely to have been associated with ecological rather than genetic factors. Myndus crudus Van Duzee (Homoptera : Cixiidae), a vector of LY and usually the most abundant auchenorrhynchous insect on palms in LY-affected areas, was the most abundant insect collected on palms at all affected localities, except at Half Moon Resort, Jamaica where another cixiid, Nymphocixia caribbea Fennah, ocurred in higher numbers. No statistically significant differences were found in nitrogen levels in leaf samples nor in levels of soil elements and other edaphic factors at the sites with high and low LY incidence. It is suspected taht susceptibility to LY is enhanced by high soil N levels, but evidence of this study was inconclusive.
25 referencias.
The 'Malayan Dwarf' cultivar of the coconut palm, Cocos nucifera L., has been recommended of planting in Florida and areas of the Caribbean affected by lethal yellowing (LY) disease due to its high resistance to this disease. It was discovered that at 3 sites each in Florida and Jamaica there were abnormally high losses of 'Malayan Dwarf' palms due to a disease with symptoms similar to, but sometimes atypical of LY. Observations were made at these and other sites to diagnose the disease, determine its distribution, and to identify factors influencing the relatively high susceptibility of 'Malayan Dwarf' to this disease. Mycoplasma like organisms were found in tissue samples from 'Malayan Dwarf' palm with symptoms typical and atypical of LY, and diseased palms responded to oxytetracycline treatments, thus, the authors concluded that the disease was LY. Losses of palms at the 3 localities in Florida ranged from 42.9 percent to 100 percent, and at the 3 localities in Jamaica from 14 to 40 percent. The problem is so far restricted to these and possibly a few other sites. The possibility that the 'Malayan Dwarf' palms were affected by new strain of the LY agent in discussed. Although yhe 'Malayan Dwarf' at the affected sites may have been genetically impure and lacking in genes for resistance, evidence is presented that the high rate of susceptibility observed was more likely to have been associated with ecological rather than genetic factors. Myndus crudus Van Duzee (Homoptera : Cixiidae), a vector of LY and usually the most abundant auchenorrhynchous insect on palms in LY-affected areas, was the most abundant insect collected on palms at all affected localities, except at Half Moon Resort, Jamaica where another cixiid, Nymphocixia caribbea Fennah, ocurred in higher numbers. No statistically significant differences were found in nitrogen levels in leaf samples nor in levels of soil elements and other edaphic factors at the sites with high and low LY incidence. It is suspected taht susceptibility to LY is enhanced by high soil N levels, but evidence of this study was inconclusive.
Keywords: Amarillamiento letal; Enfermedades de las plantas.; insectos vectores; Myndus crudus.; Palma de aceite