Asian Citrus Psyllid

Asian Citrus Psyllid [Diaphorina citri Kuwayama].  The Asian citrus psyllid (ACP) was found accidentally in May 2006 when a resident of Waiakea, a suburban residential area adjacent to and southwest of Hilo on the Island of Hawaii, submitted a branch from a navel orange tree that was infested with aphids to the HDOA Lanikaula Office for control recommendations. 

During microscopic examination of the aphids by PPC Branch personnel, one adult psyllid and some nymphs were found. Since no psyllids occur on citrus in Hawaii, the psyllid was believed to be the ACP on the basis of literature information about its recent invasion in Florida. Transmission of digital photos of the specimens initially, followed by the shipment of  mounted specimens to the USDA Systematic Entomology Laboratory in Beltsville, Maryland, confirmed the identification as D. citri.

The association of the ACP as the primary vector of citrus greening disease (CGD), known in Asia as Huanglongbing (HLB), resulted in the immediate shipment of a sample of chlorotic foliage from the infested tree at the Waiakea residence to the National Plant Germplasm and Biotechnology Laboratory in Beltsville, MD. The results were negative for CGD, caused by the bacterium Liberibacter asiaticus. However, only one citrus foliage sample has been sent to the USDA lab for detection of the bacterial DNA. Funds are being sought to ship more samples for diagnosis.

By the end of May 2006, surveys of East Hawaii had been made from Waimea to South Point Road by a joint effort of HDOA personnel (PQ and PPC Branches) and USDA-APHIS-PPQ personnel stationed in Hilo.  The ACP distribution on the Big Island was determined to be extend from the original detection site in Waiakea north to Papaikou, southeast to Kalapana, and southwest to Glenwood and Ainahou Ranch (within Hawaii Volcanoes National Park). 

Island-wide surveys for the psyllid continued through June. Preliminary surveys of all districts except North Kona for the ACP were completed with negative results. Surveys focused on mock orange, Murraya paniculata (also known as orange jasmine), because it is the preferred host of the ACP, and on residential citrus plantings because of limited commercial plantings in Hawaii. No ACP was detected during cursory surveys in West Hawaii.

A GIS map has been generated by the Hilo PPC staff to show its range of establishment.  Samples of mock orange foliage infested with psyllid nymphs have been collected from several sites around Hilo to hold for parasitoid emergence. None had been recovered by the end of June. Some ladybird beetles, including Halmus chalybeus (Boisduval), Olla v-nigrum (Mulsant), and Coccinella septempunctata L., have been observed in association with the ACP nymphs.