First report of coconut lethal yellowing disease in Guatemala

Abstract

The Atlantic coast of Guatemala runs between Belize and Honduras; two countries in which coconut lethal yellowing (LY) disease is highly active (Harrison et al., 2002). Coconut palms (Cocos nucifera, Atlantic tall ecotype) with symptoms indicative of LY (Harrison & Jones, 2003), including premature nutfall, necrosis of immature inflorescences, progressive frond yellowing and eventual death of the palm, were first observed at several sites along the coast during 2000. However, the syndrome differed from that reported for LY, as inflorescence necrosis was evident after, rather than before, frond yellowing. Tissues from trunks, young leaves or inflorescences were sampled from palms with and without symptoms at Estero Lagarto, Finca Baltimore, Santa María del Mar and Punta Manabique. Total DNA was extracted from tissues by a small-scale method and tested for phytoplasma DNA by a nested PCR using phytoplasma universal rRNA primer pair P1/P7, followed by LY group-specific primer pair LY16Sf/LY16Sr (Harrison et al., 2002). RFLP profiles obtained by digesting the nested PCR products with HinfI endonuclease (Harrison & Jones, 2003) were identical for all phytoplasma-positive Guatemalan palms and matched rDNA profiles of Honduran and Florida isolates of the LY phytoplasma included for comparison. LY phytoplasma was detected in all of the palms with symptoms (8/8), but none (0/8) of the symptomless palms tested positive. These results were confirmed later at the Centro de Investigación Científíca de Yucatán and the University of Florida using either LY group-specific or LY pathogen-specific PCR (Harrison et al., 1994). Following this initial survey, more LY-diseased coconut palms have been sighted at other locations along the Atlantic coast, but as of 2003, LY has not been seen during surveys of coconut populations along the Pacific coast of Guatemala. This is the first report of coconut lethal yellowing disease in Guatemala.