HortScience (2011) 46, 730-735
Lisa Keith, Tracie Matsumoto, Kate Nishijima, Marisa Wall and Mike Nagao (2011)
Field survey and fungicide screening of fungal pathogens of rambutan (Nephelium lappaceum) fruit rot in Hawaii
HortScience 46 (5), 730-735
Abstract: Rambutan (Nephelium lappaceum Linn.) is a tropical fruit in Hawaii that has increased in value in the niche market of exotic fruits. The primary limitation to preharvest and postharvest quality is the occurrence of fungal diseases of the fruit. A survey of rambutan disease was conducted at orchards 9.7 km south and 29.0 km north of Hilo, HI, to determine the main fungal pathogens affecting preharvest fruit quality. Pericarp of rambutan fruit revealed brown to black lesions that progressed to blackening and drying of the fruit with some fruits becoming totally mummified. Four fungi consistently isolated from symptomatic fruit included Lasmenia, Pestalotiopsis, Phomopsis, and Colletotrichum spp. Over the 2-year sampling period, disease incidence from more than 300 fruits sampled was 84.6%. Nine rambutan cultivars were evaluated for disease incidence under field conditions. Disease incidence was greater than 90% for 'Sitangku' and 'R167' but less than 60% for 'Chompoo'. Twelve fungal isolates from infected fruit were selected for further characterization (six Lasmenia isolates and two isolates each of Pestalotiopsis, Phomopsis, and Colletotrichum). Morphology, colony characteristics, and pathogenicity of the isolates were examined. The optimum growth temperature for all fungal isolates ranged between 22 and 28 °C. Molecular methods were used to confirm the identity of the fungi. The fungal isolates were evaluated for in vitro baseline sensitivities for mycelial growth for fungicides registered for use in Hawaii (Abound® and Trilogy®). Abound® was more effective at inhibiting fungal growth than was Trilogy®; however, efficacy appeared to be influenced by fungal genera. Inhibition of fungal growth by Abound® ranged from a 76% reduction for Lasmenia to a 23% reduction for Phomopsis isolates.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Lisa M. Keith, Kate A. Nishijima
Research topic(s) for pests/diseases/weeds:
control - general
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Colletotrichum (anamorphic genus) | Rambutan (Nephelium lappaceum) | U.S.A. (Hawaii) | ||
| Lasmenia (genus) | Rambutan (Nephelium lappaceum) | U.S.A. (Hawaii) |
