Studies On Occurrence And Control Of Main Pests In Flowers Plants Field In Shanghai

The investigation of arthropod community composition in the habitat of ornamental plants in Shanghai was conducted from February 2006 to January 2007. Based on the classification, there were 121 species of phytophagous arthropods, 22 species of predators, 12 families of parasitoids and 13 families of scavengers. The relative abundance of phytophages, predators,parasitoids and scavengers were 78.10%, 5.61%, 2.44% and 13.85%, respectively. Bemisia tabaci and Frankliniella intonsa were the most abundant pest species. Orius strigicollis, Pardosa astrigera and Theridion octomaculatum were the predominant predators in flowers plants. In the field grown Chinese rose, phytophages represented most part of all arthropods collected. Among the phytophages, F. intonsa and Myzus persicae were dominant species. O. strigicollis and Misumenops tricuspidatus were the most predominant predator species. Both of the species richness and diversity index were largest in October 2006 and from May to June in 2007.The correlation between population dynamics of main pests in flowers B. tabaci, F. intonsa and M. persicae, and temperature and relative humidity were analyzed. The results indicated all the factors, mean minimum temperature, mean maximum temperature, mean temperature, mean minimum relative humidity, mean maximum relative humidity and mean relative humidity could affect the population dynamics.Relationship between the density of B. tabaci and M. persicae, and gas exchange of gerbera daisies and chrysanthemum were studied. Net photosynthetic rate, stomatal conductance, transpiration rate and intercellular CO2 concentration were measured. The results showed that there was no obvious relationship between the whitefly density and gas exchange of gerbera. However, aphid injury reduced chrysanthemum photosynthetic rate immediately after aphid removal, and there was a significant correlation between aphid density and photosynthetic rate (R2=0.4953). No significant correlation between aphid density and stomatal conductance, transpiration rate or intercellular CO2 concentration was observed. Photosynthetic rate recovered to levels comparable to those untreated plants 1 d after aphid removal. The implications of this work for the evaluation of an economic injury level and economic threshold for green peach aphid on chrysanthemum were discussed.The yellow sticky trap sheet could effectively trap the whitefly, on which smeared cooking oil and engine oil. This experiment was characterized with numerous sources of raw materials, easy operating, safety and non-toxic, no pollution and reuse of the yellow board.The functional response of O. strigicollis to F. intonsa was studied in laboratory experiments. O. strigicollis demonstrated a Holling type II functional response to F. intonsa. Predation rate varied with the densities of F. intonsa. A 1 to 11 ratio was recorded to be an optimal proportion of O. strigicollis to F. intonsa. Estimated attack coefficient and handling times by the disc equation were 0.025 h-1 and 1.52 h, respectively.The functional response of O. strigicollis on the third instars of M. persicae was examined on three composite plants Dendranthema morifolium, Gerbera jamesonii and Calendula officinalis. Logistic regression analysis revealed that the functional response of O. strigicollis was of type II on all host plants. The amount of prey consumption was significantly different between the three host plants.Over all prey densities, more aphids were eaten on chrysanthemum than on gerbera and calendula. Based on the disc equation, a higher attack coefficient was found on chrysanthemum, followed that on calendula and gerbera. Handling times were significantly longer on calendula than chrysanthemum and on gerbera. This study suggests that host plants affected the functional response of O. strigicollis to M. persicae.