Biological Activity of trans-2-Hexenal Against Bradysia odoriphaga (Diptera: Sciaridae) at Different Developmental Stages

trans-2-Hexenal, one of the C6 green leaf volatiles, is potentially useful for the control of Bradysia odoriphaga Yang et Zhang. In this study, the biological activity of trans-2-hexenal on B. odoriphaga was assessed in the laboratory. trans-2-Hexenal was observed to kill B. odoriphaga in different developmental stages at a relatively low concentration under fumigation. The respiration rate in the male treatment group decreased from 131.44 to 4.07 nmol/g·min with a prolonged fumigation time, while the respiration rate in females decreased from 128.82 to 24.20 nmol/g·min. Male adults exhibited a more sensitive electroantennogram response at 0.05–500 μl/ml at the dose of 10.0 μl than female adults. Moreover, trans-2-hexenal had a repellent effect on adults based on the results with a Y-tube olfactometer at 10.0 μl, as shown by the deterrent rate of male and female adults with 96.67% and 98.33%, respectively. The results showed that trans-2-hexenal had good biological activity in different developmental stages of B. odoriphaga, which could reduce the need for, and risks associated with, the use of traditional insecticides and enable nonharmful management.     

环氧乙烷对松木片中松材线虫的熏蒸效果

在18℃、60%-70%RH的室内条件下,研究了不同剂量环氧乙烷(EO)对松木片中松材线虫的熏蒸效果.结果表明:EO对松材线虫具有一定的熏杀作用,松材线虫的死亡率(y)与EO剂量(x)呈线性相关[y=-44.998+1.838x(p=0.00948)],EO对松材线虫的LD50为51.686 g.m-3,LD99.9为78.835 g.m-3;松木片对EO的吸附作用很大,当EO剂量为56 g.m-3时,24 h浓度值为1.157 g.m-3,吸附量达到89.974 mg.L-1,且吸附量随剂量的增大而增加,吸附主要发生在熏蒸开始后4 h内,4 h吸附率可达94%以上.因此,不推荐将EO用于集装箱内松木片松材线虫的处理.     

磷化氢抗性锈赤扁谷盗和其它几种害虫的实仓熏蒸效果比较

在实仓条件下储藏小麦的高大平房仓,采用高浓度磷化氢环流熏蒸抗性锈赤扁谷盗Cryptolestes ferrugineus(Stephens)、嗜卷书虱Liposcelis bostrychophila Bodonnel、谷蠹Rhizopertha dominica(Fabricius)、赤拟谷盗Triboliumcastaneum(Herbst)和米象Sitophilus oryzae(Linnaeus)等5种不同抗性水平害虫,记录磷化氢浓度变化、熏蒸过程中及培养一段时间后的害虫死亡情况等。主要结果为:抗性较低的米象和赤拟谷盗在熏蒸第7 d即都全部死亡,此过程中磷化氢的浓度处于300 mL/3→500 mL/m3的上升阶段;抗性中等水平的谷蠹在磷化氢浓度保持在300 mL/m3以上19 d的时间才能全部死亡,而高抗性书虱和锈赤扁谷盗则需要在第21 d和27 d后才全部死亡,此过程中磷化氢的浓度处于前期上升阶段和500 mL/3→200 mL/m3的下降阶段。结果表明,有效熏蒸书虱和锈赤扁谷盗不仅需要较高的磷化氢浓度,更需要在较高磷化氢浓度下保持更长的熏蒸时间。     

川贝雪梨脆片变温压差膨化干燥应用技术

以雪梨为主要原料,配以川贝母、百合、甘草等药典成方药食同源中药熏蒸,强化雪梨产品的食疗功效;在生产过程中利用真空膨化干燥设备,应用变温压差膨化干燥技术,形成了较完善的川贝雪梨脆片变温压差膨化干燥技术工艺。     

三株解磷细菌对磷矿粉PRⅣ溶解效果的研究

选取3株具有代表性的解磷菌株,分别为Erwinia.sp.(Y2)、Pseudomonas.sp.(Y3)、Serratia.sp.(Y4),采用砂培试验,对培养物依次进行直接浸提、熏蒸、消煮,分别测定浸提液的有效磷含量.结果表明:培养物经消煮后,其有效磷含量均显著增加,解磷量介于55.154μg·g-1～75.498μg·g-1之间,其中,Y3、Y4菌株的解磷量较高,具有较好的应用前景.     

柠檬醛对绳状青霉抑制作用研究

为了弄清理化因素及作用方式对霉菌的影响,采用滤纸片法与挥发性物质活性检测法,研究不同浓度柠檬醛对绳状青霉(Penicillium funiculosum)的抑制作用,并检测不同处理时间对孢子萌发率的影响。结果表明,柠檬醛采用滤纸片法与挥发性活性物质检测法对P.funiculosum的最小抑制浓度(MIC)分别为6.0与3.0 mg.mL-1。在3.0 mg.mL-1浓度下处理10 min孢子萌发受到明显抑制,萌发时间比对照推迟6 h,萌发率降低21.7%;而处理120 min萌发时间比对照延迟10 h,萌发率降低83.8%。柠檬醛可通过熏蒸的方式对P.funiculosum起到较好的抑制作用。这为工农业产品防治霉菌的危害提供了新的理论依据。     

Two-year investigations on the integrated control of weeds and root parasites in Virginia bright tobacco (Nicotiana tabacum L.) in central Italy

The current revision of pesticides in the EU, including those for soil disinfection, will necessitate the introduction of alternative integrated methods for the control of weeds and parasites in tobacco production in Italy. The present study compared the effect of some soil fumigants, biocontrol agents, cover crops and mulching for the control of tobacco weeds and root parasites. The results show that the different soil fumigants had an important role in increasing tobacco yield, due to their ability to control weeds and the nematodes Meloidogyne incognita and Meloidogyne javanica. In particular, a typical nematicide like 1,3-dichloropropene did not control only nematodes but also Portulaca oleracea, a common weed in Italian tobacco fields. Fenamiphos, although showed a certain efficacy in controlling root-knot nematodes, did not generally have a satisfactory activity at the dose of 40 g m⁻¹; cover crops like Trifolium squarrosum and Eruca sativa and a commercial formulation composed by the endomycorrhizal fungi Glomus spp., the antagonistic fungi Trichoderma spp. and bacteria including Pseudomonas, Bacillus and Streptomyces (Micosat F, CCS Aosta, Italy), were not able to control root tobacco diseases. The investigations confirmed that a prolonged monoculture causes a reduction of black root rot. Soil fumigation and the use of Good Agricultural Practices (GAP), influencing the inoculum density of Chalara populations, can contribute to the maintenance or to the establishment of particularly unfavourable conditions for the saprophytic growth of the pathogen, leading to a lower development of the disease.     

Influence of erosion on soil microbial biomass,abundance and community diversity

This study aimed to determine microbial biomass carbon and microbial abundance immediately after, and two years after, forest soil erosion, so as to estimate the degree of damage, including the rate of recovery of microorganisms, in each area. It also aimed to determine the community diversity, and to establish relationships between microbial biomass, microbial abundance and the physico‐chemical properties of the soil. Three different study areas in Hiroshima Prefecture, Japan, were used. One undisturbed area and two eroded areas (one immediately after and one two years after erosion). The analysis of variance showed a highly significant difference in microbial biomass carbon and abundance between the study areas. The undisturbed area showed the highest value, followed by the area eroded two years ago, then lastly the area studied immediately after the erosion. The biomass carbon was highly correlated with gram positive bacteria with r² = 0·983, p < 0·01. The biomass carbon and microbial population were shown to be significantly correlated to the soil's physico‐chemical properties, such as pH, moisture content, water‐holding capacity and CN ratio. However, CN ratio proved to be closely correlated to biomass carbon with r² = −0·978, p < 0·01, to Gram‐positive bacteria with r² = −0·977, p < 0·01, to Gram‐negative bacteria with r² = −0·989, p < 0·01 and to fungi with r² = −0·977, p < 0·01. The undisturbed area showed a highly diverse community in both of the restriction enzymes used, followed by the area affected by erosion two years ago, then the area immediately after erosion. Copyright © 2004 John Wiley & Sons, Ltd.     

房式仓粮堆膜下通风与环流熏蒸共用系统改造试验

对现有房式仓进行局部改造,设计,安装了适当的装置构成既能进行粮堆膜下环流熏蒸,又能进行膜下通风降温降水的“二合一”系统。经实践证明系统设计合理,改造方便,操作简便,投资少,通风,熏蒸效果良好。     

Surface application of ammonium thiosulfate fertilizer to reduce volatilization of 1,3‐dichloropropene from soil

Atmospheric emission of the soil fumigant 1,3‐dichloropropene (1,3‐D) is of environmental concern because of its toxicity and carcinogenicity. Thiosulfate fertilizers have been found to rapidly transform 1,3‐D in soil to non‐volatile ions which are less toxic. We investigated the use of surface application of ammonium thiosulfate (ATS) for reducing 1,3‐D volatilization. In packed soil columns, emission of 1,3‐D applied by sub‐surface injection decreased with increasing ATS application rate and the amount of water used for delivering ATS. When ATS was applied in 9 mm water at 64 g m⁻², total 1,3‐D emission was reduced by 61%. The reduction was 89% when ATS was applied at 193 g m⁻². Bioassays showed that ATS application did not affect the effectiveness of 1,3‐D for controlling citrus nematodes. In field plots where a 1,3‐D emulsified formulation was applied via sub‐surface drip, surface spray of ATS reduced 1,3‐D emissions by 50%, and by 71% when the surface was also covered with polyethylene film. ATS application had no effect on the efficacy of root‐knot nematode control or tomato yields. These results suggest that surface application of thiosulfate fertilizers may be a feasible and effective strategy for minimizing 1,3‐D emissions. © 2000 Society of Chemical Industry