小油菜不同播期与密度下黄条跳甲为害情况的研究

本文报道了黄条跳甲类害虫在油菜不同播期与密度条件下的发生为害情况，从四个播种日期与五个播种密度的试验结果表明，黄条跳甲随播期推迟发生为害加重，播种量大，为害较严重，并且，在西宁地区为害小油菜的主要种类是黄宽条跳甲，其次为黄曲条跳甲，二者比例为３．３：１，适时早播，严格控制播种量是减轻黄条跳甲发生为害的重要农业技术措施。

A Preliminary Study on the Occurrence of Striped FleaBeetles under the Different Sowing Time and Density ofSpring Rape (Brassica campestris L.)

This paper reports striped flea beetles occurred in the different sowing times and densities of spring rape. The results obtained from 4 sowing times and 5 sowing densities indicated that striped flea beetles damaged rape seedlings increasingly when sowing time was postponed and sowing density was enlarged. There were 2 kinds of the beetles which damaged spring rape in Xining, dominant species was Phyllotreta humilis, then was P. vittata, and in a ratio of 3. 3 to 1. It's very important to begin sowing early properly and to control sowing density strictly in order to diminish the pests.