The response of phosphine-resistant lesser grain borer Rhyzopertha dominica and rice weevil Sitophilus oryzae in mixed-age cultures to varying concentrations of phosphine

The response of Rhyzopertha dominica and Sitophilus oryzae (both phosphine-resistant) in mixed-age cultures to phosphine at fixed concentration-time products (CT) of 10,500 to 168,000 microliters litre 1 h (ppm h) with either constant, rising or falling concentrations for 7 days was studied at 27 (+/- 2) degrees C. At lower CT products, rising concentrations of phosphine led to significantly fewer survivors of R dominica and S oryzae. Conversely, exposure to falling concentrations of phosphine resulted in significantly more survivors. The influence of changing concentrations of phosphine was more pronounced in S oryzae than in R dominica. In the latter, at the lower CT products of 21,000 and 42,000 microliters-1 h, the adult stage proved to be most tolerant, contrary to the accepted belief that the egg or pupal stage are always more tolerant to phosphine. The results indicate that application of phosphine in rising concentrations is more effective than in constant or falling concentrations.     

Fumigant toxicity of<Emphasis Type="Italic">Eucalyptus blakelyi</Emphasis> and<Emphasis Type="Italic">Melaleuca fulgens</Emphasis> essential oils and 1,8-cineole against different development stages of the rice weevil<Emphasis Type="Italic">Sitophilus oryzae</Emphasis>

Essential oils extracted fromEucalyptus blakelyi (1,8-cineole, 77.5%),Melaleuca fulgens (1,8-cineole, 56.9%) and 1,8-cineole were shown to have fumigant toxicity against different development stages ofSitophilus oryzae. The eggs ofS. oryzae were the most tolerant, followed by pupae, larvae and adults in that order.M. fulgens oil,E. blakelyi oil and 1,8-cineole at 100 μl per liter of air gave, respectively, LT₅₀ values of 16.2, 17.4 and 9.1 h for adults, 31.1, 19.3 and 17.5 h for larvae, 55.6, 75.2 and 39.7 h for pupae, and required >7 days for eggs. Only 1,8-cineole (200 μl ⁻¹ air) gave a significant egg kill by 7 days and the LT₉₅ was 134.5 h. 1,8-Cineole could be a useful new fumigant. http://www.phytoparasitica.org posting Oct. 3, 2004.     

Extraction of allyl isothiocyanate from horseradish (Armoracia rusticana) and its fumigant insecticidal activity on four stored‐product pests of paddy

BACKGROUND: Isothiocyanates (ITCs) extracted from Armoracia rusticana Gaertn., May & Scherb. have been shown previously to have insecticidal activity. Allyl isothiocyanate (AITC), a major component of ITCs with high volatility, was therefore extracted using different methods and tested as a fumigant against four major pest species of stored products, maize weevil Sitophilus zeamais (Motsch.), lesser grain borer Rhizopertha dominica (F.), Tribolium ferrugineum (F.) and book louse Liposcelis entomophila (Enderlein). RESULTS: Whereas there was no significant difference between hydrodistillation and supercritical carbon dioxide fluid extraction in extraction rate for AITC from A. rusticana, both methods resulted in higher extraction efficiency than water extraction. AITC fumigation showed strong toxicity to the four species of stored‐product pests. Adult mortality of 100% of all four pest species, recorded after 72 h exposure to AITC fumes at an atmospheric concentration of 3 µg mL^?1, showed no significant difference from that of insects exposed to phosphine at 5 µg mL^?1, the recommended dose for phosphine. CONCLUSIONS: The results suggest good insecticidal efficacy of AITC against the four stored‐product pests, with non‐gaseous residuals on stored products. AITC obtained from A. rusticana may be an alternative to phosphine and methyl bromide against the four pest species. Copyright © 2009 Society of Chemical Industry     

胡芦巴不同溶剂粗提物对主要储粮害虫的生物活性研究

本研究采取回流提取法,以豆科植物胡芦巴为材料,选用无水乙醇、氯仿、乙酸乙酯、丙酮、石油醚5种溶剂进行粗提。并以主要的储粮害虫玉米象、锯谷盗为试验对象,对粗提物的触杀、驱避作用进行了测定。结果表明：5种溶剂对胡芦巴的提取率为乙醇〉乙酸乙酯〉氯仿〉丙酮〉石油醚。各粗提物对2种储粮害虫表现出较强的触杀作用。胡芦巴的乙醇粗提物（上层）及乙酸乙酯粗提物对玉米象的触杀活性最强,处理48h后的LD5。分别为0．328mg／cm2、0．334mg／cm2。触杀活性最低的是石油醚粗提物,处理72h后的LD50为0．582mg／cm2。对锯谷盗而言,乙醇（上层）、乙酸乙酯、石油醚、氯仿4种溶剂粗提物的触杀作用均比丙酮粗提物的强。所有粗提物对2种储粮害虫也都表现出一定的驱避作用,玉米象与锯谷盗的驱避率之间差异不显著。     

电子束辐照谷物中玉米象不同虫态的生物效应

用ИЛУ 6М2 型电子加速器对玉米象成虫以及隐藏于小麦籽粒中的玉米象卵、幼虫和蛹进行辐照效应试验。结果表明 ,1 80Gy以上的剂量可以完全阻止谷物中幼虫和卵发育为成虫 ;在此剂量下有少量蛹可羽化为成虫 ,但存活力受严重影响 ,30 0Gy以上辐照的蛹即使羽化也在短时间内死亡 ;成虫被 30 0Gy的电子束辐照后寿命大缩短 ,在 1 4d内完全死亡。 30 0Gy电子束辐照剂量可以作为辐照有效防治玉米象的剂量。     

夹带剂对胡芦巴超临界CO_2萃取物的生物活性影响

以乙醇、乙酸乙酯、氯仿3种溶剂作为夹带剂,对胡芦巴植物种子干粉进行超临界CO2萃取(SCFE),其中以乙醇作夹带剂的萃取得率最高,所得到的超临界CO2萃取物对玉米象、谷蠹、杂拟谷盗成虫的触杀活性均较强.     

谷蠹、米象和锈赤扁谷盗的PH_3抗性品系对杀螟松和氯化苦的交互抗性研究

用 4个谷蠹、5个米象和 4个锈赤扁谷盗磷化氢抗性品系进行了磷化氢抗性品系害虫对杀螟松和氯化苦的交互抗性试验。对杀螟松的抗性试验用FAO滤纸药膜法进行 ,对氯化苦的抗性试验参照FAO磷化氢抗性测定法 ,在干燥器内熏蒸处理。试验结果表明米象和锈赤扁谷盗的磷化氢抗性品系对氯化苦和杀螟松没有交互抗性。但两个谷蠹的磷化氢抗性品系对杀螟松表现出一定抗性 ,其抗性系数分别为 2 .94和 5.2 4。由于并非所有的磷化氢抗性品系都对杀螟松具有抗性 ,所以我们估计这种抗性是这些害虫以前接触过此种杀虫剂或类似的杀虫剂所引起的。所有的谷蠹品系对氯化苦都没有抗性。上述结果表明 ,为控制害虫对磷化氢抗性发展而采用轮换使用药剂策略时 ,氯化苦和杀螟松都是合适的轮换对象。     

阿维菌素和毒死蜱对玉米象和赤拟谷盗的毒力测定

用3种低毒农药对生活在稻谷中的玉米象和赤拟谷盗2种储粮害虫用喷雾法进行室内毒力测定。结果表明:(1)1.8%阿维菌素乳油(EC)、2%阿维菌素微囊悬浮剂、48%毒死蜱乳油(EC)对玉米象的致死中剂量(LD50)分别为0.01mg/kg、0.07mg/kg、4.65mg/kg,而对赤拟谷盗的LD50分别为0.08mg/kg、0.50mg/kg、5.89mg/kg;(2)在相同剂量下,3种药剂中以1.8%阿维菌素EC对2种害虫的毒杀速度最快;(3)玉米象比赤拟谷盗对这3种药剂更敏感。建议采用1.8%阿维菌素EC、2%阿维菌素微囊悬浮剂、48%毒死蜱EC防治玉米象的使用剂量分别为0.05mg/kg、0.80mg/kg和2.0mg/kg,而防治赤拟谷盗则分别为0.05mg/kg、0.80mg/kg和8.0mg/kg。     

非化学处理对玉米象成虫的控制作用初探

通过试验初步研究半导体激光、紫外线以及与植物精油结合处理等非化学处理对玉米象成虫的控制作用;结果表明:低功率范围的半导体激光处理对玉米象的控制作用不佳;紫外线照射各处理组对玉米象均表现出一定的控制作用,其中254nm 20min处理组玉米象死亡率最高,并在第4d、5d与其它各组达到显著差异;物理、生物结合处理对玉米象成虫的控制作用较好,紫外(254nm 20min) 枫杨处理组最好,从第2d开始起表现出最有效的控制作用,且与其他各组差异显著,在第4d、第5d时死亡率达到了100%;非化学处理对玉米象有较好的处理作用,结合处理效果更佳,控制机理和具体参数有待于进一步研究.     

艾绿士对三种主要储粮害虫的毒力测定

采用药膜法室内测定新型微生物杀虫药剂艾绿士（有效成分为乙基多杀菌素）对三种主要储粮害虫玉米象、锈赤扁谷盗和谷蠹的作用效果,以储粮保护剂保粮磷作为对照。结果表明：当浓度为16μg/cm2,作用时间48 h时,艾绿士丙酮溶液对三种害虫的防治效果均达97%以上;艾绿士对玉米象、锈赤扁谷盗和谷蠹等三种害虫具有良好的触杀作用,其中对锈赤扁谷盗触杀效果最好;艾绿士对玉米象、锈赤扁谷盗和谷蠹的LC50值分别为5.1630μg/cm2、1.9337μg/cm2、5.2517μg/cm2;艾绿士对锈赤扁谷盗和谷蠹的毒力高于保粮磷3倍多,对玉米象的毒力略高于保粮磷。本试验结果对生物药剂艾绿士的有效成分乙基多杀菌素在储粮害虫生物防治方面的合理应用提供了基本依据。