Fumigant Toxicity and Repellence Activity of Camphor Essential Oil from Cinnamonum camphora Siebold Against Solenopsis invicta Workers (Hymenoptera:Formicidae)

The red imported fire ant (RIFA) Solenopsis invicta Buren causes severe damage to humans and animals as well as the environment. Chemical treatment is the main strategy of RIFA management, which also is potentially toxic to the environment. Plant essential oils (EOs) are considered as potential substance that can be used to control insects. This study aimed to identify the chemical composition of camphor EO and investigate the insecticidal activity on RIFAs. The chemical composition of the EO was analyzed by gas chromatography/mass spectrometry and gas chromatography with flame ionization detection. Results revealed that 36.61% camphor and 30.05% cineole were the major components. The insecticidal activity of camphor EO was assessed against RIFA workers by conducting two different bioassays: fumigant toxicity and repellence. Fumigant toxicity assay results showed that the lethal dose (LC₅₀) of the EO at 24 h was 1.67 and 4.28 μg/ml for minor and major workers, respectively; knockdown time (KT₅₀) was 10.82 and 14.73 h. At 2.55 μg/ml, the highest average mortality of the ants was 84.89% after 72 h. Camphor EO exhibited fumigant toxicity against minor and major workers as indicated by the effects on attacking, feeding, and climbing behaviors. This EO was also strongly repellent to the two size workers of the colony as observed in their behavior against Tenebrio molitor treated with 5 µl EO. The fumigant toxicity and repellence of camphor EO against RIFA indicated that this substance could be a potential alternative for the development of eco-friendly products used to control pests.     

芸香科三种植物精油对家蝇的熏杀活性及其混配增效作用

用水蒸汽蒸馏法从岭南花椒Zanthoxylum austrosinense果实、椿叶花椒Zanthoxylum ailanthoides果实和四数九里香Murraya hunanensis叶中提取植物精油,采用三角瓶密闭熏蒸法测试3种精油对家蝇的熏杀、击倒作用及其混配增效作用。3种植物精油对家蝇的6 h熏杀LC50值分别为岭南花椒果实精油7.55μg/cm3、椿叶花椒果实精油11.08μg/cm3、四数九里香叶精油11.41μg/cm3;在熏蒸浓度均为10μL/345 m L时精油对家蝇的熏蒸击倒效果KT50分别为岭南花椒果实精油16.80 min、椿叶花椒果实精油24.69 min、四数九里香叶精油23.33 min。将岭南花椒果实精油与椿叶花椒果实精油以体积比7:3和9:1混配,其共毒系数分别为130.00和136.08;将岭南花椒果实精油与四数九里香叶精油以体积比9:1混配,其共毒系数为123.71。研究结果表明,3种植物精油对家蝇均有熏杀、击倒作用,其中岭南花椒果实精油与椿叶花椒果实精油或四数九里香叶精油以适当比例混配后具有增效作用,可利用其开发高效环保的植物源灭蝇剂。     

薰衣草油与肉桂油对朱砂叶螨的生物活性和行为分析

为明确在室内条件下薰衣草油、肉桂油对朱砂叶螨Tetranychus cinnabarinus(Boisduval)的生物活性,采用喷雾、熏蒸法测定了薰衣草油和肉桂油对朱砂叶螨的触杀活性、产卵抑制活性和熏蒸活性,并分析了2种精油的亚致死剂量对雌成螨运动行为的影响。结果表明:与肉桂油相比,薰衣草油对朱砂叶螨的触杀活性较强,经浓度为1%的薰衣草油喷雾处理后,雌成螨、若螨24 h后的死亡率分别为64.07%和52.22%,LC_(50)分别为0.41%和0.89%;浓度为2%的薰衣草油对雌成螨产卵的抑制作用最强;与肉桂油相比,薰衣草油的熏蒸活性也较强,熏蒸雌成螨6、12和24 h后的死亡率分别为70.37%、85.19%和95.19%,LD_(50)分别为0.94、0.59和0.39μL;随精油剂量增加雌成螨运动轨迹紊乱,触壁反射活动减少,移动范围明显减小,而移动频率先升高后降低。研究表明,与肉桂油相比,在朱砂叶螨的生物防治中薰衣草油具有更高的应用价值。     

甲酸乙酯的施药高度对仓内空间杀虫效果的影响

在储粮容量7000t的高大平房仓空仓内,设置一个高7.50 m、直径300mm的熏蒸室,分别在7.50m、5.61m、3.74m、1.87m和0.1m的高度放置试虫,先后从0.10m、3.74m和7.50m的高度施药,测定了甲酸乙酯对处于不同高度的赤拟谷盗(Tribolium castaneum(Herbst))和谷蠹(Rhyzopertha dominica(Fabricius))成虫的杀虫效果。结果为:在0.10m高度施药,甲酸乙酯对于靠近施药点的试虫可完全致死,而在1.87m及其以上高度处的害虫死亡率均显著低于施药点的死亡率。在高度3.74m处施药,施药点及其以下两种害虫的死亡率均显著大于施药点以上的害虫死亡率,3.74m及其以下的谷蠹均完全死亡,赤拟谷盗的死亡率则出现了0.1m处100%,1.87m和3.74m处则分别只有96.7%和81%。经7.50m高度施药,0.10m高度处的害虫死亡率达100%,且害虫死亡率出现自下而上递减的结果。本实验表明,作为熏蒸剂的甲酸乙酯在空间被施用后,静态条件下向上扩散且有效杀虫的高度小于2m;在高空施药后主要扩散趋势为向下运动(下沉),对施药点以下的害虫效果较好,建...     

不同土壤熏蒸剂对烤烟苗床杂草的药效试验

以烟草品种龙江911为供试材料,对适每地、维博亩和斯美地这3种不同土壤熏蒸剂防除烟草苗床杂草效果进行了试验。结果表明,适每地和斯美地这两种土壤熏蒸剂对苗床杂草均有较好的防除效果。综合防除效果及安全性等因素．以斯美地效果最理想,其次是适每地,均可在黑龙江省烟区推广使用。     

土壤处理对连作西洋参生长及根病发生的影响

采用田间随机区组试验，选择前茬种过西洋参的老参地，用大扫灭、二硫化碳、多菌灵等3种低毒化学农药和紫苏根作为添加物进行土壤处理，处理后播种西洋参，调查出苗、存苗、根的生长及根病情况。探讨化学农药及植物添加物处理老参地土壤对改善重茬西洋参生长及减少病害的作用。试验结果表明，98%大扫灭粉剂5g/m2~15g/m2、二硫化碳液剂20ml/ m2进行土壤熏蒸处理，对提高重茬西洋参的出苗率、保苗率、产量，以及减轻根部病害均有较好的效果；添加紫苏根50g/m2~100g/m2的作用主要表现为可以提高根重，多菌灵消毒的作用效果不明显。     

土壤处理对连作西洋参生长及根病发生的影响

采用田间随机区组试验,选择前茬种过西洋参的老参地,用大扫灭、二硫化碳、多菌灵等3种低毒化学农药和紫苏根作为添加物进行土壤处理,处理后播种西洋参,调查出苗、存苗、根的生长及根病情况.以探讨化学农药及植物添加物处理老参地土壤对改善重茬西洋参生长及减少病害的作用.98%大扫灭粉剂5～15g/m2、二硫化碳液剂20ml/m2进行土壤熏蒸处理.对提高重茬西洋参的出苗率、保苗率、产量,以及减轻根部病害均有较好的效果;添加紫苏根50～100g/m2的作用主要表现为可以提高根重,多菌灵消毒的作用效果不明显.老参地使用土壤熏蒸剂及适宜的植物添加剂,对克服西洋参连作障碍具有一定作用.