Tomato (Lycopersicon esculentum), pepper (Capsicum annuum), corn (Zea mays), French bean (Phaseolus vulgaris), soybean (Glycine max), winged bean (Psophocarpus tetragonolobus), lima bean (Phaseolus lunatus), field pea (Pisum sativum), moth bean (Phaseolus aconitifolins), and heliconia (Heliconia bihai) were evaluated as alternative hosts of Xanthomonas campestris, the causal agent of a leaf blight of onion (Allium cepa). On legumes, bacterial growth occurred in planta, and visible disease symptoms developed. From 19 commercial onion genotypes screened for leaf blight resistance, two cultivars, H-942 and H-508, were generally free of symptoms and had restricted bacterial growth in planta. These are the first known reports on alternative hosts of the bacterium and on resistance in onion to leaf blight.

Coconuts (Cocos nucifera) are an important small-holder's crop in many tropical countries and are used to enhance esthetics of coastal areas. Lethal yellowing (LY) is the single most important plant disease affecting the coconut industry in Jamaica. It affects many palm species in Jamaica, Florida, and Guatemala. This coconut disease was first recorded in Grand Cayman Island in 1834 and Jamaica in 1884. Symptoms of LY disease include premature nut fall, necrosis of the inflorescence, yellowing of the leaves, and defoliation. Thirty-eight coconut palms displaying symptoms indicative of LY disease were sampled in April, 2005 at several locations in Nevis. Immature leaf tissues (leaf bases adjacent to the apical meristem) and nondestructive (boring with a bit and braces) samples were collected from disease and healthy control coconut trees. DNA was extracted (2). The first round of polymerase chain reaction (PCR) with phytoplasma universal primer pair P1/P7 (1,3) resulted in an rDNA fragment of 1.8 kb, and a subsequent nested PCR using LY16-23Sr/LY16Sf primers yielded an amplicon of 1.74 kb (4). Purified product was cloned for sequencing. Sequences obtained were analyzed with Vector NTI Software Suite. The sequence of LYN 18-3 was entered in Genbank and Accession No. DQ378279 was assigned. LYN 18-3 has approximately 99% homology with LY Phytoplasma U18747 from Florida (Manila palm [Veitchia merrillii]). The disease-associated phytoplasma was reliably detected in immature tissues and trunk phloem at the onset of foliar symptoms in palms by PCR. On the basis of the results obtained from this study, it is clear that LY phytoplasma (16SrIV group) was found in the samples collected from Nevis. To our knowledge, this is the first report on lethal yellowing disease in Nevis. References: (1) S. Deng and C. Hiruki. J. Microbiol. Methods 14:53 1991. (2) J. J. Doyle and J. L. Doyle. Focus 12:13, 1990. (3) N. A. Harrison et al. Ann. Appl. Biol. 141:183, 2002. (4) C. D. Smart et al. Appl. Environ. Microbiol. 62:2988, 1996.

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