温度对高氮气调中米象各虫态致死时间和发育的影响

Comparison on Lethal Time and Development Duration of Different Stages of Sitophilus oryzae(L.)Influenced by Temperature in Controlled Nitrogen Atmosphere

明确氮气气调中温度对隐蔽性害虫各虫态致死时间的延迟程度及差异,可为气调杀虫时间的科学掌控提供参考。研究了在98%氮气浓度和(75±5)%RH下18、23和28℃时米象Sitophilus oryzae(L.)成虫和隐蔽于粮粒内的卵、幼虫和蛹在不同时间的死亡率、致死时间以及羽化出成虫的时间。18℃温度下达到100%死亡率的时间为25 d,比23℃和28℃时相应延迟了6 d和12 d。18℃下气调致死虫卵、幼虫、蛹和成虫的LT 50值(半数致死时间)分别为9、8、11和7 d,LT 99值(99%个体致死所需时间)分别为24、21、26和17 d;23℃时相应LT 50值为6、5、7和5 d,LT 99值为19、16、21和11 d;28℃时LT 50值为3、3、4和3 d,LT 99值为11、10、12和7 d。98%氮气气调后残存米象隐蔽虫态均可发育,与正常气体环境相比18℃时从卵发育至成虫的历期最大可延迟27 d,温度降低可导致发育历期延长更为明显。米象不同虫态对氮气气调耐力由大到小为:蛹>卵>幼虫>成虫,氮气气调杀除米象时应以完全杀死隐蔽发生的蛹为目标。

It can provide significant reference for scientific insect management to know the degree of delayed full killing time of insects at low temperature in controlled nitrogen atmosphere,especially for the immature stages hidden in cereal kernel.The mortality,exposure time of full mortality and the development duration of Sitophilus oryzae(L.)were assayed at temperature of 18,23 and 28℃with concentration 98%N 2 plus 2%O 2.The exposure time of full mortality was 25 d at 18℃,which was delayed 6 and 12d corresponded to 23 and 28℃.At 18℃,the LT 50 values to the eggs,larvae,pupae and adults were 9,8,11 and 7 d respectively,and the LT 99 were 24,21,26 and 17 d relatively.At 23℃,the LT 50 were 6,5,7 and 5 d,LT 99 were 19,16,21 and 11 d to eggs,larvae,pupae and adults.At 28℃,LT 50 were 3,3,4 and 3 d,and LT 99 were 11,10,12 and 7 d correspondingly to the stages.The hidden stages of S.oryzae can still develop from immature stages to adults in the controlled environment of 98%N 2.The developmental duration could be extended at lower temperature.The duration from egg to adult emergence could be delayed 21 d in the treatment environment of 98%N 2 compared with in the normal air condition.The order of tolerance to controlled nitrogen atmosphere against different stages of S.oryzae was pupa>egg>larva>adult.The results showed that the main target of controlling S.oryzae successful by controlled nitrogen was killing the most tolerant stage-pupa which hidden in cereal kernel.