Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 7, 2007
Publication Date: November 15, 2007
Citation: Rossman, A.Y., Goenaga, R.J., Keith, L.M. 2007. First report of Dolabra nepheliae on rambutan and litchi in Hawaii and Puerto Rico. Plant Disease. 91:1685. Interpretive Summary: Fungi are a very large and diverse group of organisms that cause serious diseases of crop and forest plants. Accurate knowledge of fungi is critical for controlling the diseases they cause. Rambutan and lychee are tropical plants that produce delicious edible fruits. In this research a fungus that causes a canker disease of both rambutan and lychee was discovered for the first time in Hawaii and Puerto Rico. This pathogen was originally described from Malaysia and has been reported from Australia. Knowledge of the identity of this plant pathogen is the first step in developing measure to control this disease of these specialty crops. In addition, knowing that this pathogen occurs outside its initial range is useful for plant regulatory and quarantine officials working to control the spread of this disease.
Technical Abstract: A stem canker disease on rambutan (Nephelium lappaceum L.) and lychee (Litchi chinensis Sonn. (Sapindaceae) was found on plants in Hawaii and Puerto Rico. The fungus associated with cankers was identified as Dolabra nepheliae C. Booth & Ting. Numerous black, stipitate, elongate ascomata were produced within cracks of the cankers. The ascomata contain elongate, bitunicate asci amid unbranched interthecial,elements and thin, cylindrical, hyaline ascospores measuring 96-136 × 2.5-3.5 'm. This fungus was originally described from Malaysia on N. lappaceum and is also known on pulasan (N. mutabile Blume) in Australia. Classified as a ‘minor disease’, the canker appears to be relatively common in Hawaii and was most likely introduced into Puerto Rico on imported germplasm. Efforts are underway to study potential damage of this disease as well as mechanisms for control, including introduction of disease resistant clones. Specimens have been deposited at the U.S. National Fungus Collections (HI on Nephelium, PR on NepheliumI, PR on Litchi). A specimen of D. nepheliae on Litchi chinensis was previously collected from Hawaii by G. Wong and C. Hodges and deposited as BPI 626373. Dolabra nepheliae has not been previously reported on Litchi and Nephelium in Hawaii and Puerto Rico.