Anzeiger für Schädlingskunde, Pflanzenschutz, Umweltschutz (1997) 70, 97-101
B. Liu and C. Sengonca (1997)
Seasonal population dynamic and within-plant distribution of the whitefly, Aleurotuberculatus takahashi David et Subramaniam (Hom., Aleyrodidae), and its parasitoid, Eretmocerus longipes Compere (Hym., Aphelinidae) in citrus and jasmine plantations in Fuzhou region of the southeastern China
Anzeiger für Schädlingskunde, Pflanzenschutz, Umweltschutz 70 (5), 97-101
Abstract: Field investigations on seasonal population dynamic and within-plant distribution of the whitefly Aleurotuberculatus takahashi David et Subramaniam (Hom., Aleyrodidae), and its parasitoid, Eretmocerus longipes Compere (Hym., Aphelinidae) in citrus and jasmine plantations were conducted at Fuzhou, Fujian, PR China in 1996.
Population levels of the whitefly and its parasitoid were approximately one times higher on jasmine plantation than on citrus. The seasonal trend of the whitefly parasitization rate on citrus was similar to that on jasmine. Maximum parasitization rates on citrus and jasmine were determined on 30. Sept. valuing 17.5% and 32.0% respectively. Later in the season this rate gradually dropped gradually down to zero level till the end of sampling period. Populations of A. takahashi and E. longipes were differently distributed in regard to leaf age on citrus and to plant layers on jasmine. A. takahashi was most abundant on youngest citrus leaves (age class I) averaging 14.03 indiv./leaf and on leaves in the top layer of jasmine with 20.02 indiv./leaf, while E. longipes preferred to settle on youngest citrus leaves (age class I) (3.41 indiv./leaf) and on leaves in the middle layer of jasmine (2.95 indiv./leaf). Beside the whitefly population was distributed in a contagious pattern with K>8 on mature citrus leaves (age class III), the whitefly and parasitoid populations displayed an aggregated distribution pattern with 0<K<8 on all the leaf ages of citrus and all 3 layers of jasmine. Furthermore, the distribution of the parasitoid was even more aggregated than that of the whitefly within all leaf position tested. Regression analysis was used to fit a model of the parasitism related to the indices of whitefly (K1)/parasitoid (K2) (Y = 0.1770-0.0048X, r = 0.7850, p < 0.05), where a = 0.1770 represented the average saturation parasitism by E. longipes and b = 0.0048 indicated a negative relation between the parasitism and the indices of K1/K2. From the equation it was concluded that the fitness of spatial distribution pattern between the whitefly A. takahashi and its parasitoid E. longipes was optimal with of K1/K2-indices below 5 resulting in the highest parasitism in the field.
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Link to article at publishers website
Database assignments for author(s): Cetin Sengonca
Research topic(s) for pests/diseases/weeds:
population dynamics/ epidemiology
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation
population dynamics/epizootiology
