Abstract
This trial investigated whether Pythium splendens or Radopholus similis was the primary causal agent of a root rot and decline observed in Anthurium andraeanum plantings in Jamaica. Affected plants were stunted, off-colour and unthrifty, and the roots rotted often to the extreme. Leaves turned yellow then dry, suckering was inadequate, and bloom production was reduced both in quantity and quality. Most plants eventually died, leaving beds weedy and dilapidated. Plots were fumigated with Vorlex (600 mL 10 m-2 PPF), or suckers were dipped in 1500 parts per million (ppm) oxamyl (nematicide dip), or 3800 ppm prothiocarb (fungicide drench) solutions, before planting. Plots were treated with either phenamiphos [granular (G)] [20 kg active ingredient (ai) ha-1] (PAP), ethoprop (G) (11.2 kg ai ha-1) (EAP), diazinon (emulsifiable concentrate) (37 L ai ha-1) (DAP), or drenched with 2700 ppm prothiocarb or 1000 ppm metalaxyl solutions (FAP) every four months for the first year, then every six months thereafter. The 12 treatments were PPF; PPF-ND; PPF-PAP; PPF-EAP; PPF-ND-PAP; PPF-ND-EAP; PPFND-DAP; PAP; EAP; PPF-FD-FAP; FAP; and control. Phenamiphos- or ethoprop-treated plants showed low levels of root rot, and produced three and four times greater root mass, respectively. These plants were three and four times, respectively, as large as the control plants, and those in the other treated plots, roots of which showed high levels of rotting. Furthermore, the ethoprop-treated plants bore 50% more suckers and bloom, and the phenamiphos-treated plants twice or more as many suckers and blooms compared with plants receiving the other treatments. After 42 months, ethroprop- or phenamiphos-treated plots were still thriving and productive, while plants in the control and otherwise-treated plots were in a state of advanced decline. Diazinon was not effective as a nematicide. This trial confirmed the nematode to be the primary causal agent of anthurium root rot and decline in Jamaica.
