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ARS Home » Pacific West Area » Hilo, Hawaii » Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center » Tropical Plant Genetic Resources and Disease Research » Research » Publications at this Location » Publication #418326
Research Project: Conservation, Management, and Genetic Improvement of Tropical and Subtropical Fruit, Nut, and Beverage Crop Germplasm for the Pacific Region

Location: Tropical Plant Genetic Resources and Disease Research

Title: An improved sampling and baiting method for Phytophthora tropicalis and P. heveae detection in Macadamia integrifolia

Author
item FERENCE, CHRISTOPHER - Oak Ridge Institute For Science And Education (ORISE)
item Keith, Lisa

Submitted to: Plant Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2024
Publication Date: 9/25/2024
Citation: Ference, C.M., Keith, L.M. 2024. An improved sampling and baiting method for Phytophthora tropicalis and P. heveae detection in Macadamia integrifolia. Plant Journal. 13:2687. https://doi.org/10.3390/plants13192687.
DOI: https://doi.org/10.3390/plants13192687

Interpretive Summary: Macadamia nut production in Hawai'i is a $30.9 million industry. Macadamia quick decline (MQD), caused by two Phytophthora species, has been a persistent problem in commercial orchards on Hawai'i Island. Early, accurate detection is key for effective management. To aid in this process, an improved field-friendly sampling and baiting method for Phytophthora tropicalis and P. heveae detection in Macadamia integrifolia was developed.

Technical Abstract: Macadamia nuts are, economically, the second most important crop in the state of Hawai'i. A recent decline in yield and acreage has been attributed to insect damage and diseases such as Macadamia Quick Decline (MQD) caused by Phytophthora tropicalis and P. heveae. To develop an improved methodology for diagnosis and treatment for MQD, investigations were undertaken to better understand the pathosystem of the disease. These investigations included sampling from multiple locations from sectioned trees utilizing two methods of tissue collection and isolations using two baiting techniques. Collection of tissue from the cambium and phloem of trees after scraping away the bark and in locations of recent or current sap exudation using a narrow diameter steel awl proved to be an efficient means for molecular detection of the MQD pathogens from infected trees exhibiting MQD symptoms. In addition, a more efficient and cost-effective baiting method using apple puree was developed.