长沙地区豇豆荚螟的生物学特性及消长规律研究

通过室内饲养和田间调查,研究了豇豆荚螟（Maruca testulalis Geyer）幼虫的生物学特性.结果表明：在长沙地区豇豆荚螟一年发生6-7代,幼虫共5龄.1-5龄幼虫头壳宽度分别为0.197±0.001 mm、0.325±0.009 mm、0.536±0.003 mm、0.889±0.006 mm、1.471±0.004 mm,相邻头壳宽度比值约为1.64.在18℃时,1-5龄幼虫的历期分别是3.1±0.81 d、3.0±0.8 d、2.5±0.6 d、3.7±0.9 d和5.7±1.5 d;在32℃时,1-5龄幼虫的历期分别为1.7±0.7 d、1.1±0.3 d、1.2±0.5 d、1.2±0.5 d、1.3±0.6 d.幼虫期的发育起点温度是9.857℃;有效积温为187.2℃,幼虫在花、荚上的危害盛期为5月22日-6月11日、8月19日-9月8日.

Biological Characteristics and Occurrence Regularity of the Legume Pod-borer of Maruca Testulalis Geyer' Larvae

The bionlogys of M. testulalis Geyer＇ larvae was studied. The results showed that M. testulalis had 6 -7 generations per year in Changsha region. M. testulalis had five stadia altogether. The helmet breadth of M. testulalis for the 1^st instar, 2^nd instar, 3^rd instar, 4^th instar, and 5^th instar larvae were determined respectively as 0. 197 ± 0.001 mm,0. 325 ± 0.009 mm,0.536 ± 0.003 mm,0. 889 ± 0. 006 mm, 1. 471 ±0.004 mm. The ratio of the neighboring helmet breadths was 1.64. At 18 22 ,the developmental durations of the 1st 1^st larvae were 3.15 ±0.81 d, 3.0 ±0.8 d, 2.5 ±0.7 d, 3.7 ±0.9 d and 5.7 ± 1.5 d, respectively. At 32 22 ,those were 1.7 ± 0.6 d, 1.1 ± 0.3 d, 1.2 ± 0.5 d, 1.2 ± 0.5 d and 1.3 ± 0.6 d. The developmental threshold temperature of M. testulalis larva was 9.9 22 ,and the effective accumulated temperature was 187.2 22. The investigation on population dynamics of M. testulalis was studied by field investigation. The results showed that the occurrence peaks of M. testulalis in flowers and pods were May 22^nd to June 11^th and August 19^th to September 8^th respectively.