| Summary: | 碩士 === 國立高雄師範大學 === 生物科學研究所 === 87 === Abstract
The whitefly (Pealius spina Singh) infested condition of bo trees (Ficus religiosa) in Kaoshiung was assessed in December 1997(winter) and August 1998(summer), respectively. Five leaves from each of 20 trees were selected. The bo trees were more seriously infested in summer than in winter. The highest infested level was on Ishin road and the lowest infested level was on Lin-ya 1st road in winter. In summer, the highest and lowest infection was appeared on the Kaoshiung commerial high school and Chenchin road, respectively. The results of principal component analysis exhibited that the bo trees with larger chest height width and more diverse surrounding plants were less infested.
I investigated the population dynamics of the whitefly nymph and adult with five sampling sites on Kaoshiung from April 1998 to March 1999. The highest number of nymphs were appeared on September 1997, and the highest intensity of nymphs and adults were found in the Kaoshiung commercial high school. However, the lowest number of nymphs and adults were separately located on the Chenchin road and the National Sun Yat-sen University.
The effect of pruning on the whitefly population dynamics at Jencho road was investigated. A tree-cutting level (the branch length was less than 2m after pruning) presented both the highest number of whitefly nymphs and adults. The increase of air pollution materials, including dust, total suspended paticulates , chloride, and air temperature, would suspress the appearance of whitefly nymph.
The Taylor's power law and Iwao's patchiness regression indicies exhibited that the whitefly was clumping distribution on all sampling units at different sites. The optimal sample sizes at different sites also were calculated and the sequential sampling procedures at different sites were also developed.
I recommend to prune bo trees in winter for reducing the infested level and increasing the aesthetic feeling. The plant diversity and abundance around bo trees should be increased. Chemical control should be targeted on those smaller and infested bo trees to decrease the pesticide usages.
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