豆秆黑潜蝇田间分布型与抽样方法的初步研究

作者应用分层随机抽样法进行研究,以查明豆秆黑潜蝇在夏大豆田内的分布型因各代密度高低而发生的变化;分析样点含量对分布型的影响,找出适宜的抽样单位;了解豆秆黑潜蝇在豆株主茎及分枝内的分布情况,并考虑用局部代替整株。此法为昆虫田间分布型的研究提高了效率和质量。

PRLIMINARY STUDIES ON THE DISTRIBUTION PATTERN AND METHODS OF SAMPLING OF THE SOYBEAN AGROMYZID FLY (Melanagromyza sojae Zehnte)

Data of infesfation were collected from each of several soybean fields in a stratified random manner in 100×100 M² "blocks", each consisting of five to sixteen 25×25 M² plots. In each plot 5 adjacent plants were sampled down the row on each of 2 adjacent rows at 4 locations within the plot. The paired 5-plant samples produced a total of eight 5-plant samples/plot or 40 plants. For each block 320 plants (8×40) to 640 plants(16×40)were sampled. The soybeans were takan back to the laboratory for testing. At the sample points the Ist plant was inspected and appropriate data were recorded. Similar data were recorded after inspection of the next successive 4 plants, resulting in a tabulation of 1-and 5-plant sample units, and the 10-plants unit were consisted of 2 adjacent 5-plants. These data were used to construct observed frequency distructions of 64-128 5-plant samples for each field. The scientific calculator (Casio fx-140) was used to obtain the frequency distribution fit to the patterns of distribution. The samples from relatively low-density populations of generation on July agreed with Poisson expectations while samples indicating relatively dense insect populations of generations on August or September with expectation of the negative binomial or Neyman contagious distribution. The number of plants per sample unit and the population density of fly in the different part of plant all influenced the statistical distributicn of the samples.