| Pseudophacopteron alstonium Yang et Li, a Psylloidea insect feeding on Alstonia scholaris, causes the formation of galls on the leaves of its host plant, which seriously affects the growing development and ornamental value of Alstonia scholaris. Base on the pilot study of Biological characteristics of Pseudophacopteron alstonium, some physiological and biochemical indexes such as the photosynthesis, the contents of nutritive materals and secondary substances, protective enzyme activitise etc. were tested; some insecticides were bioassayed on nymphae and imago to detemine their toxicities. The results were as follows:1. Pseudophacopteron alstonium has3stages, the nympha has5instars, their body colour ranged from yellow to pitchy, and the ommateum was ovoid. The1st instar has an oblong body, a ruffled periphery and with no wing pad.2nd instar has a light yellow body, its wing pad was visible, the cerores in terminal abdomen secreted waxiness.3th instar was bigger than the2nd, its feelers and wing pad were plainly visible.the4th instar was very active although it has a round body, the colour in its terminal abdomen was brown. Yellow was the5th instar prevailing body colour, but the wing and abdominal segment were brown, the dorsal shield has mahogany brindle,the large rounded ommateum trun from wine to gray with the growing, and it has3orangeyellow ocellus.2. Pseudophacopteron alstonium has no overwintering phenomenon, there were several generations in one year and the overlap of generations was very common. The galls induced by Pseudophacopteron alstonium on Alstonia scholaris were of aggregation distribution, the distribution on all derections or two stories has no significant difference.3. After be damaged by Pseudophacopteron alstonium, the diurnal fluctuation of net photosynthetic rate, stomatal conductance and transpiration rate were all showed:the heslthy leaves> the leaves with galls but no emergence hole>the lesves with galls and emergence hole. The diurnal fluctuation of intercellular CO2concentration were the lesves with galls and emergence hole> the leaves with galls but no emergence hole> the heslthy leaves. The contents of chlorophyll were significantly reduced in damaged leaves as compared with that of the healthy leaves.4. Feeding by Pseudophacopteron alstonium induced significantly reduced in contents of soluble sugar. For instance, in all gall-development stages, the contents of soluble sugan in galls are obviously lower than tahat in healthy leaves,in the3rd stage, the ratio of the soluble sugar in galls and CK was0.29. Feeding by Pseudophacopteron alstonium induced significantly incressed in contents of soluble proteins. The contents of soluble proteins in galls were significant higher than that in healthy leaves except in the first stage and the ratio in galls and CK was1.76in the4th stage.5. Feeding by Pseudophacopteron alstonium can induced significantly changes in the Protective enzyme activity. There are maredly differnce in the activty of POD, SOD, CAT, PPO in galling tissues and CK. For instance, in the4th gall-development tage, the ratio of POD, SOD, CAT, PPO activity in galls and CK was0.91,0.84,1.66and1.88.6. Feeding by Pseudophacopteron alstonium induced significantly incressed in contents of total phenolics and tannin. The total phenolics and tannin contents of galling tissues in the4th stage are the highest, they are1.49and2.26times as those in CK. Feeding by Pseudophacopteron alstonium induced significantly decressed in contents of flavonoids. In the3rd stage, the ratio of flavonoids contents in the galling tissues and CK was0.51.7. The insecticidal efficacy to nymphae of Pseudophacopteron alstonium was as follow: Beta-cyfuthrin>Avermectin>Avermectin-Acetamiprid>buprofezin· isoprocarb>imidacloprid. The index of relative toxicity of Beta-cyfuthrin was82.62times higher than imidacloprid.The insecticidal efficacy to Pseudophacopteron alstonium was as follow: Beta-cyfuthrin>Avermectin>Avermectin-Acetamiprid>buprofezin·isoprocarb>imidacloprid. The index of relative toxicity of Beta-cyfuthrin was36.67times higher than imidacloprid. The effect of insecticides to restrain eclosion of fifth instar was as follow: Avermectin-Acetamiprid> Avermectin> Beta-cyfuthrin> imidacloprid. |
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