黄翅菜叶蜂是四川油菜的主耍害虫之—。此虫在土壤中作土茧化蛹或幼虫在土茧内越冬。为作好预测工作,须对此由进行虫情检查。我们在进行蛹态调查中,以往采用双筛筛除法,土样首先经铁筛(孔径0.3厘米)除去石砾,再用孔径0.3厘米的铁筛除去细泥土,在利于筛中的土粒检查土茧,统计土茧数。此法常因土壤湿度较大,土壤粘重,土茧易与土粒混淆,难以识别,影响数据的准确性,且工效低。有时土壤过湿或过粘重,影响工作的正常开展。后来我们试用水漂浮法进行调查,经过实际调查,已获得良好效果。 具体作法 用孔径0.3厘米、长100—120厘米、宽60—100厘米、高20—30厘米的铁筛或分筛一个,选择有水源的地方,将筛放入水中,筛底四角垫上石头,便于泥土漏下,筛边露出水面2—3厘米,以免漂浮的土茧遗出筛外。安置好后,将土样倒入筛内,用手迅速搅动,使泥 Yellow-winged leaf bee is the main pest of Sichuan rape -. The insects in the soil for soil cocoon pupation or larvae wintering in soil cocoon. In order to make a good prediction, we must carry out insect inspection on this basis. We are in the pupae survey, the past, the use of dual sieve removal method, soil samples first iron sieve (aperture 0.3 cm) to remove the gravel, and then use a 0.3 cm diameter iron sieve to remove fine soil, in favor of sieve soil particle inspection Soil cocoon, the number of soil cocoon statistics. This method is often due to soil moisture greater soil sticky, soil cocoon easily confused with soil particles, difficult to identify, affecting the accuracy of the data, and low efficiency. Sometimes the soil is too wet or too viscous, affecting the normal work. Later, we tried the water floating method for investigation. After the actual investigation, we have achieved good results. The specific approach with an aperture of 0.3 cm, length 100-120 cm, width 60-100 cm, 20-30 cm high iron sieve or a sieve, select a place where water, the sieve into the water, Easy to drain the soil, sieve exposed 2-3 cm surface, so that floating soil cocoon left out of the sieve. After placement, the soil sample into the sieve, quickly agitated by hand to make mud