Influence of Citrus Huanglongbing Pathogen (Candidatus Liberibacter asiaticus) on Life History Traits and Population Parameters of Its Vector – Asian Citrus Psyllid (Diaphorina citri Kuwayama)
Date Issued
2007
Date
2007
Author(s)
Tsai, Xin-Yi
DOI
en-US
Abstract
This research was conducted to compare the differences in the life history traits and population parameters between Asian citrus psyllids (Diaphorina citri Kuwayama) with or without citrus Huanglongbing (HLB) pathogen (Candidatus Liberibacter asiaticus) (Las). The life table data were collected and then subjected to the age-stage, two-sex life table analysis. The polymerase chain reaction (PCR) was used to monitor the pathogen at the death of each psyllid. The results showed that the life span of Las-infected (Las (+)) psyllids were relatively longer than those of Las-free (Las (-)) ones, with 35.2 and 33.4 d. The Las appeared to cause psyllids to develop abnormally or emerge unsuccessfully. It also occasionally prolonged the period of 5th instar up to 40 d, resulting in their failure to reach adulthood. Some Las (+) adults even had abnormal wings after emergence. These abnormalities had never been observed in the Las (-) adults. Adult females had the preference of laying eggs during their early reproductive period, and daily oviposition pattern occurred primarily in two periods, one morning (7:30-9:30 a.m.) and the other late afternoon (3:30-5:30 p.m.). Comparing to Las (-) females, the Las (+) females also had longer pre-oviposition period (10.5 vs. 5.7 d), late first reproduction age counted since birth (27.6 vs. 21.9 d), and lower fecundity (18.6 vs. 29.6 eggs/♀). When comparing the population parameters between psyllids with or without being infected with the pathogen, the Las (+) psyllids had a longer mean generation time (T) (29.09 vs. 22.87 d) and doubling time (Dt) (10.35 vs. 6.36 d). The intrinsic rate of increase (rm) of the Las (-) female (0.1112 d-1) was 1.61 times higher than that of the Las (+) female (0.0689 d-1); the net reproductive rate (R0) was 1.70 times higher (12.27 vs. 7.22 offspring/female/generation); and the finite rate of increase (λ) was 1.04 times higher (1.1176 vs. 1.0712 d-1). In the stable stage distribution of Las (+) and Las (-) psyllids, the total percentage of immature was 84.25% and 88.58%, respectively. And the total percentage of the Las-transmitting individuals, including the 4th, 5th instar nymphs and adults, of Las (+) psyllids was 48.03%, which was higher than that of the Las (-) ones (34.08%). It is concluded that Las amounts found in psyllids would affect their life history traits and population parameters. Different amounts of Las found in a psyllid would cause different physiological responses. These Las amounts were closely related to the amount of Las acquired in the initial acquisition period. Furthermore, when the proportion of the infected citrus trees increased, the Las (+) psyllids would also increase. Therefore, removing and destroying infected citrus plants and improving the control of psyllid nymphs were essential to an effective field management of HLB.
Subjects
兩性生命表
Candidatus Liberibacter asiaticus
Diaphorina citri Kuwayama
生活史特徵
族群介量
two-sex life table
life history trait
population parameter
Type
thesis