Study On System Monitoring Of Occurrence Of Bactrocera Minax(Enderlein)

The Chinese fruit fiy Bactrocera minax, belonging to the order Diptera and the family Tephritidae, mainly infests citrus. It has been reported in multiple countys of Chongqing and caused enormous economic losses to fruits. In the thesis, field investigation and indoor assay methods were applied to study the occurrence dynamics of each stage and effects of environmental factors on the population of B. minax. The outcome will provide some basic theoretical information for seting up the model of forecast and calculation. This research was supported by the National Basic Research Program of China (2009CB125903) and the Special Fund for Agro-scientific Research in the Public Interest (200903047-4). The main results of the research are as follows:1 The monitor of each stage of B. minaxIn the past, the monitor of Chinese fruit fly was by using protein insect lure to catch flies while it cannot reflect occurrence dynamics of other stages of the fly. A lot of information about the laying progress, larval developing, pupation and emergencey was obtained by the combination of indoor-rearing, systematic investigation and adult trapping methods of orchard; an integrated technique system about monitoring of Chinese fruit fly was found. The data about the date of the beginning, apex and ending of the peak period of each stage of the fly were obtained by the establishment of the models and the quantitative dynamics of every stage was clarified. The results provide significant theoretical guide for occurrence date, quantitative forecast and loss evaluation.2 Effects of temperature, soil humidity and depth of buried pupae on adult emergence of B. minaxWith the objective of determining the effects of environmental factors on the adult emergence of B. minax, temperature, soil moisture content, pupae buried depth and the interactions among these three factors were analyzed with respect to the adult emergence characteristics, such as emergence percentage, survival rate, the earliest date of adult appearing, and emergence duration, using orthogonal combination experiment to develop the regression equations of above three factors at different levels. The results showed that among four equations, the partial regression coefficients of temperature were all the highest, which were 19.37,22.14,15.88 and 9.63, and the relationships were negative correlated. The adult emergence percentage and survival rate was mainly affected by soil moisture content with the partial regression coefficient of 6.92 and 12.02, and the relationships were also negative correlated. Besides, the positive correlations of the buried depth of pupae with both emergence percentage and survival rate were found with the partial regression coefficient of 2.86 and 1.39. The interactions among these factors mainly affect the adult survival rate. There were additive effects of the interaction between temperature and soil humidity, however, the interaction between temperature×pupae depth and soil humidity×pupae depth were opposite and had antagonistic effects. The results have important great significance to the occurrence forecast of B. minax.3 The spatial distribution patterns of infested fruitFrequency distribution, aggregation indices, nearest neighbor analysis and geostatistics were used to analyze the spatial distribution patterns of infested fruit. The results demonstrated that the patterns of maggot fruit were aggregating among trees while random on trees. Models of space variation were constructed at the directions of east-west and south-north based on the geostatistical method by using survey data.4 Morphology of B. minaxThe female reproductive system B. minax consists of paired ovaries and short lateral oviducts, a common oviduct, a spermatheca and accessory glands. According to the developmental characters of ovaries, the imago genital system development duration is classified into five levels:ivory-white and hyaline period, yolk deposition period, preoviposition period, highest oviposition period and later oviposition period.The ultrastructure of the external features of the third-instar larvae of both B. minax and B. dorsalis was comparatively studied by scanning electron microscopy. The antenna, maxillary palpus, oral ridges, labium, caudal segment, anterior and posterior spiracles and cephalopharyngeal skeleton were described and illustrated. Morphological characters of third-instar larvae of B. minax and B. dorsalis are different. In addition, the possible functions of sensillae are discussed in light of previously published literature.