Host Preference And Mechanism Of The Orange Spiny Whitefly, Aleurocanthus Spiniferus (Quaintance) To Different Tea Varieties

This research was conducted in the tea varieties resource garden and the net laboratory in Tea Research Institute of Fujian Academy of Agricultural Sciences from 2002 to 2004. The host selectivity of Aleurocanthus spiniferus (Quaintance) to 12 kinds of tea varieties, including Yulong, Dangui, Jiulongpao, You3, You510, FuyunNo.6, Fuyun No. 10, Tieguanyin, Huangdan, G31, Baijiguan and Maoxie, was studied by field investigation on density of Aleurocanthus spiniferus, by investigations on the oviposition preference, the number of puparium per unit and the generational survival rate in the net laboratory. Influence of 8 kinds of tea varieties on the development and propagation of Aleurocanthus spiniferus was researched. The morphological characteristics and anatomical structure of tissue in leaves and the main contents of biochemistry of new shoot in 9 kinds of tea varieties were mensurated. By correlation analysis, the influential mechanism of Aleurocanthus spiniferus on host plant preference to different tea varieties was discussed, in order to provide theoretical basis for breeding and utilizing resistant tea varieties and control to Aleurocanthus spiniferus. The main results were as follows:1. The selectivity of Aleurocanthus spiniferus to 12 kinds of tea varieties was studied by the host plant selectivity indexes including field pest density, the number of oviposition and puparium per unit and the generational survival rate of Aleurocanthus spiniferus in the net laboratory. The results showed that Aleurocanthus spiniferus were not attracted evidently by You 3, You 510, Dangui, Yulong, and Jiulongpao, but attracted strongly by G31, Tieguanyin, Baijiguan and Fuyun No. 10. The correlation between the number of oviposition per unit and field pest density, the number of puparium per unit as well as the generational survival rate was extremely-significant (P<0.01), and the correlative coefficients were 0.9200 (P<0.01), 0.9011 (P<0.01), and 0.9128 (P<0.01),respectively. Therefore, the host preference of Alewocanthus spiniferus to different tea varieties could be basically reflected by the oviposition number per unit in the net laboratory.2. The effect of tea varieties with different host preference of Aleurocanthus spiniferus on the development and propagation of Aleurocanthus spiniferus was significant. The results indicated that the development duration of stages of Aleurocanthus spiniferus in Yulong, Dangui and You 3, with weak host preference to Aleurocanthus spiniferus, was longer than that in G31 and Fuyun No. 10 with strong host preference. The survival rate of development stages of Aleurocanthus spiniferus in Yulong, Dangui and You 3 was lower than that in G31 and Fuyun No. 10, the ratio of female and male of Aleurocanthus spiniferus in Yulong, Dangui and You 3 was less than that in G31 and Fuyun No. 10, the number of oviposition per female in Yulong, Dangui and You 3 was also less than that in G31 and Fuyun No. 10.3. The results showed that the oviposition number per unit in the net laboratory had significantly positive correlation with stoma density (P<0.05), nearly significantly negative correlation with thickness of keratode layer on subepidermis (P=0.0613), significantly positive correlation with thickness of palisade tissue( P<0.05 ), significantly positive correlation with thickness of spongy tissue (P<0.05 ). The generational survival rate of Aleurocanthus spiniferus in the net laboratory had nearly significantly positive correlation with stoma density in leaves(P=O.O5O5), significantly negative correlation with thickness of keratode layer on subepidermis (P<0.05) and extremely-significant negative correlation with the thickness of subepidermis (P<0.01) and palisade tissue (P <0.01), and non-correlation with thickness of spongy tissue (p > 0.05 ) .i.e. the less the stoma desity in tea leaves and the thicker the thickness of subepidermis and keratode layer on subepidermis and palisade tissue and the thinner the thickness of spongy tissue were, the less oviposition number of Aleurocanthus spiniferus and the lower of the generational survival rate were, which determined the morphological non-preference mechanism of tea varieties.4. The oviposition preference of Aleurocanthus spiniferus in the net laboratory had...