Submitted to: Florida Entomological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2006
Publication Date: July 23, 2006
Citation: Hall, D.G. 2006. Asian citrus psyllid - biology and seasonal ecology [abstract]. The 89th Annual Meeting of the Florida Entomological Society Meeting, July 23-26, 2008, Jupiter Beach, Florida. p. 6-7. Technical Abstract: The seasonal ecology of Diaphorina citri was investigated in a non-irrigated citrus grove of mature orange trees beginning January 2005 in east central Florida. No insecticides were applied during the study. Predators including lady beetles, lacewings and syrphid flies were observed during the study, and a population of the parasitoid Tamarixia radiata was established in the grove. Phenology of D. citri was assessed weekly using counts of adults on yellow sticky cards (7.8 x 12.8 cm) placed in trees, counts of adults per pair of mature leaves, and counts of adults, eggs and nymphs on vegetative flush shoots. A mean of 150 adults/trap/wk was observed during one week of the study, but peak means of 30 to 50 adults/trap/wk were more common. A mean of 0.8 adults/leaf pair was observed during one week of the study, but peak means of 0.1 to 0.2 adults/leaf pair were more common. Peak means of 50 to 65 eggs/flush shoot and 40 to 65 nymphs/flush shoot were observed during the study. A mean of 2.0 adults/flush shoot was observed during one week of the study, but peak means of 0.5 to 0.8 adults/flush shoot were more common. Relative abundance of vegetative flush was assessed weekly by counting the number of foliar flush shoots within a 15x15x15 cm frame slipped into the outer edge of a tree with the end of a branch inside the frame. Means of 1 or more shoots per sample generally indicated an abundance of vegetative flush, with means of 1 to 4 shoots per sample constituting a minor to moderate flush and means of 5 to 10 constituting a major flush in this particular grove. Sticky traps and samples of mature leaves indicated that adult D. citri were present continually in the trees but sometimes at very low levels for extended periods of time. During fall and winter 2005-2006 when little or no flush was produced by the trees, mean numbers of adults dropped from 3.5/trap/wk to 0.0-0.5/trap/wk. Immatures and adults were consistently abundant during the summer months in association with vegetative flush and sometimes abundant during other times of the year in association with flush. No data were collected on infestations of D. citri on blooms, but general observations indicated populations did not develop on young blooms present in the grove during March 2005 nor during March 2006. Observations during a late bloom during May 2006 revealed D. citri readily oviposits and develops on young developing blooms. Earlier research (1998-2000) showed peak D. citri populations in Florida during the summer, relatively large populations during October-December, and low populations from December through May. Evidence to-date indicates outbreaks of D. citri in Florida citrus consistently occur during the summer but may develop at any time of the year depending on environmental conditions and the availability of flush.