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掌握红铃虫幼虫在棉田的分布型及其抽样技术,对正确估计田间虫口密度有重要作用。我们于1977～1978年,在嘉定县封浜公社、上海县七一公社及本院试验场进行了这项工作,现介绍如下。一、调查方法选择长势不同的棉田19块,其中棉株开花期(虫害花中第一代幼虫高龄期)调查15块田;棉株结铃期(青铃中第三代幼虫高龄期)调查4块田。每块棉田均在离田埂2米左右开始抽样。样本数量为:虫害花内幼虫每块田连续调查40行,每行50株;青铃内幼虫按随机法取每株的上、中、下部直径在2厘米以上的青铃各一只,连续取20行,每行25株。按顺序记录每株的幼虫数。
Mastering the distribution pattern and sampling technique of pink bollworm larvae in cotton field plays an important role in the correct estimation of insect population density in the field. We conducted this work from 1977 to 1978 at Fengbang commune in Jiading county, Qianyi commune in Shanghai county and our own test site. First, the survey method to choose 19 different cotton fields, including cotton flowering (pest flower first generation larvae age) survey 15 fields; cotton boll period (the third generation of young adults in the Qingling age survey) 4 fields. Each piece of cotton fields are about 2 meters away from the farm to start sampling. The number of samples: pest insects per field of continuous investigation of 40 rows of lines, 50 lines per line; Qingling internal larvae randomly selected by the upper, middle and lower diameter of more than 2 cm in diameter each one green bell, continuous Take 20 lines, 25 lines per line. The number of larvae per plant was recorded in order.