谷蠹和米象对小麦的虫蚀粒和千粒重影响比较研究

COMPARISON ON INFLUENCE OF SITOPHILUS ORYZAE (L.) AND RHIZOPERTHA DOMINICA (F.) ON BORED KERNEL PERCENTAGE AND THOUSAND SEED WEIGHT OF WHEAT

在20-28℃环境中,研究了无虫小麦样品分别感染0、4、6、10头/kg谷蠹和米象成虫后的20周内小麦虫蚀粒率和千粒重的变化情况.结果表明：感染谷蠹的样品均在第2周时虫蚀粒率出现显著升高,而感染米象的样品则到第10周后虫蚀粒率才显著升高.第18周时感染4、6、10头/kg的谷蠹样品虫蚀粒率分别达到13.67%、16.00%和22.00%,感染米象的小麦虫蚀粒率相应达到12.67%、14.33%和18.67%.20周后不同密度谷蠹的小麦中虫蚀粒率分别达到25.00%、31.00%和39.33%,千粒重分别从43.87g下降到35.37g、33.98g和31.36g.相应米象样品的虫蚀粒率则分别为22.67%、29.33%和31.33%,千粒重分别下降到36.18g、34.90g和33.42g.谷蠹比米象可早6周引起小麦虫蚀粒率显著升高,从内部隐蔽性为害的米象引起虫蚀粒率变化表现时间延迟.同样条件下,谷蠹引起虫蚀粒率增加的程度大于米象,谷蠹引起小麦千粒重下降的幅度则略小于米象.

We studied the bored kernel percentage （BKP） and thousand kernel weight （TKW） of wheat infested by adults of Sitophilus oryzae （L.） and Rhizopertha dominica （F.） with a population density of 0,4,6 and 10 adults per kilogram of grain at 20 to 28 ℃. The results showed that the BKP of the wheat sample infested by R. dominica had an obvious increasing in the first two weeks;the BKP of the wheat sample infested by S. oryzae increased obviously until the tenth week; in the 18th week,the BKP of the wheat sample infested by R. dominica and S. oryzae with a population density of 4,6 and 10 adults per kilogram of grain reached 13.67%, 16.00% and 22.00% ,and 12.67%, 14.33% and 18.67% ,respectively. At the end of 20 weeks,the BKP of wheat sample infested by R. dominica reached 25.00% ,31.00% and 39.33% ,and the TKW decreased from 43.87 g to 35.37 g, 33.98 g and 31.36 g respectively; the corresponding BKP of wheat sample infested by S. oryzae was 22.67 g, 29.33 g and 31.33 g,and the TKW respectively decreased to 36.18 g,34.90 g and 33.42 g. The increasing of BKP of wheat sample bored by R.dominica was six weeks earlier than that of a sample bored by S. oryzae, and the BKP change time of the wheat sample bored by S. oryzae from inside was delayed. Under the same condition, the increasing of BKP caused by R.dominica was larger than that caused by S. oryzae, and the decreasing of TKW caused by R. dominica was less than that caused by S. oryzae.