印楝素对水稻二化螟的生物活性及控制作用

 系统地研究了印楝素对水稻二化螟的生物活性及作用方式。试验结果表明，印楝素乳油对二化螟有胃毒、拒食、忌避、内吸等多种作用方式。0.75和0.50 mg/L印楝素乳油处理茭白饲喂3龄幼虫，幼虫分别于3、6 d内全部死亡；0.375、0.300和0.250 mg/L印楝素乳油低剂量处理茭白饲喂3龄幼虫，幼虫拒食率分别达94.38%、88.74%、80.07%；成虫产卵量分别下降80.70%、62.05%、40.86%。6、3和2 mg/L印楝素乳油处理初孵蚁螟，24 h内死亡率达100%。印楝素乳油对成虫产卵有显著的忌避作用。稻田喷施0.3%印楝素乳油62.5和125 mL/667 m2防治二化螟，21 d保苗效果分别为88.14%和94.13%，防治效果分别为85.36%和90.76%。表明印楝素对二化螟有较高的生物活性和理想的控制效果。     

植物乙醇提取物对荔枝蒂蛀虫的防治研究

通过室内饲养观察和田间试验,研究不同药剂对荔枝蒂蛀虫的防治效果。通过室内饲养观察,从9种植物乙醇提取物中筛选出了飞机草茎叶乙醇提取物、非洲山毛豆乙醇提取物和大叶桉叶乙醇提取物3种对荔枝蒂蛀虫成虫具有较好的产卵忌避作用的植物乙醇提取物;田间药效试验结果表明,上述3种忌避作用物质处理5d后,对荔枝蒂蛀虫的产卵防治效果分别为82.02%,82.17%,74.37%,显著高于10%高效灭百可乳油(47.57%)和90%敌百虫结晶的防治效果(35.99%)。3种乙醇提取物对荔枝果实的保果效果分别为84.21%,85.26%,80.00%,对荔枝蒂蛀虫具有较好的防治和保果效果。      

印楝种仁5种活性成分纯化与定量分析

印楝(Azadirachta indica.A.juss)种仁中含有印楝素A(azadirachtin)等活性成分,主要为四环三萜类化合物,对害虫具有显著的忌避拒食作用和生长抑制作用。本研究通过硅胶柱层析和TLC法对印楝活性物质进行分离纯化,得到印楝素A等5种高纯度印楝素同系物,采用LC-MS对其进行定性分析,鉴定5种物质分别为azadirachtin、salannin、nimbin、6-deacetylnimbin、6-deacetylsalannin,并使用HPLC对5种化合物进行定量分析。     

蟛蜞菊抽提物对花生蚜忌避及毒杀作用

用不同浓度蟛蜞菊甲醇抽提物对花生蚜选择性和非选择性忌避作用进行测定,并采用喷雾法进行蟛蜞菊抽提物对花生蚜的毒杀试验。结果表明:在选择性忌避试验中,蟛蜞菊抽提物对花生蚜具明显的忌避作用,最高忌避率达90.1％,而在非选择性忌避试验中忌避作用中等;2.5 g/L浓度蟛蜞菊抽提物喷雾处理花生蚜,第5天死亡率达93.7％,第1,3,5天致死中质量浓度(LC50)分别为1.4,1.2,0.9 g/L。蟛蜞菊抽提物有开发利用的价值。     

印楝活性物质超临界CO2萃取技术

印楝(Azadirachta indica A.Juss)种子中含有大量杀虫活性较高的柠檬素类物质,印楝油可促进柠檬素类物质的稳定性和生物活性。本实验通过超临界CO2萃取得到含柠檬素类物质和印楝油混合的粗提物,以印楝素A为检测指标,使用均匀设计优化萃取工艺的压力、温度、时间和夹带剂的体积4个因子,确定最佳提取工艺条件为压力37MPa,温度43℃,时间165min,夹带剂的体积13mL,此时印楝种仁中印楝素A萃取率为0.37%。初步测定超临界CO2萃取产物对玉米象(Sitophilus zeamais Motschulsky)成虫的驱避活性,并对该技术应用于印楝产业化的前景和可行性进行分析探讨。     

印楝素、鱼藤酮防治茶丽纹象甲成虫室内试验初报

通过室内试验研究了印楝素、鱼藤酮对茶丽纹象甲的杀虫效果。结果表明,药后2d,0.5%印楝素乳油1370倍液对茶丽纹象甲成虫的防治效果即达95.56%,药后3d达到100%,与2.5%联苯菊酯乳油1000倍液的差异不显著。0.5%印楝素乳油可作为有机茶园茶丽纹象甲防治的选择药剂。而7.5%鱼藤酮乳油750倍液,药后5d防效才达51.16%,防治效果较差。     

虫粪提取物对甜菜夜蛾成虫产卵和幼虫取食的影响

为了明确甜菜夜蛾(Spodoptera exigua Hübner)幼虫虫粪对其成虫产卵及幼虫取食的影响,采用非选择实验的方法,选用丙酮、甲醇和正己烷3种溶剂对甜菜夜蛾幼虫虫粪中的物质进行提取,然后分别测定3种溶剂幼虫粪便提取物对成虫产卵及幼虫取食的影响。结果表明:丙酮和甲醇幼虫粪便提取物对甜菜夜蛾成虫产卵量有显著的抑制作用,产卵忌避率分别为45.68%和33.21%;而正己烷提取物对成虫产卵的抑制作用不显著。3种溶剂粪便提取物对1龄和4龄幼虫的取食量(面积)均没有显著影响,但显著影响2龄和3龄幼虫的取食行为,其对幼虫的取食抑制率依次为丙酮甲醇正己烷;另外,3种溶剂粪便提取物对甜菜夜蛾幼虫的存活率无显著影响。可见,甜菜夜蛾幼虫粪便中存在对成虫产卵和幼虫取食具有抑制作用的活性物质。     

印楝提取物对瓜叶螟幼虫拒食活性的测定

研究6种印楝种仁提取物（编号为A，B，C，D，E，F）对瓜叶螟（Diaphania indica)幼虫的拒食活性。室内试验结果表明；印楝的6种提取物稀释10倍时，对瓜叶螟幼虫具有较强的拒食活性。24h非选择性拒食率分别为D100.0%，B96.1%,A93.2%,E87.5%,C76.5%,F66.6%；在稀释100倍时，处理后24h，提取物D对瓜叶螟幼虫具有较好的拒食作用，拒食率为96.5%,C61.6%，其他4种拒食活性较差。     

椰子织蛾种群繁殖特征

本文研究了椰子织蛾Opisina arenosella Walker种群繁殖的特征。2015年每月从儋州市野外采集椰子织蛾,收集当天羽化的成虫,记录成虫的产卵前期、单雌产卵量、卵的孵化率、初孵幼虫数以及成虫寿命。结果表明:1月份的气温最低,雌成虫的产卵前期最长,为(3.00±0.21)d;5、6月气温最高,产卵前期次之;其他月份的产卵前期较短。11月份椰子织蛾的单雌产卵量最高,为(231.07±19.55)粒;3、4、7、8、9、10月份的产卵量次之;1、2、5、6、12月份的单雌产卵量最低。1月份(低温)椰子织蛾卵的孵化率最低,为(2.70±2.01)%;2—12月份椰子织蛾卵的孵化率差异不显著。1月份的初孵幼虫数最少,为(4.17±2.94)头;5、6月份的较少,分别为(54.04±8.18)、(52.31±10.81)头;3月份的最多,为(87.89±14.94)头。低温使成虫的寿命延长;各月雌成虫的寿命短于雄成虫的寿命;5、6月份雄成虫的平均寿命分别为(7.08±0.68)、(7.67±0.84)d,雌成虫的平均寿命分别为(6.50±0.34)、(6.22±0.36)d,低于其他月份雌雄成虫的寿命。5、6月的高温会抑制种群的数量,是药剂防治的最佳时间。该研究为椰子织蛾的防治、预测预报等提供基础科学依据。     

不同类型水稻品种对白背飞虱忌避性、抗生性和耐害性的测定

 研究了19个不同类型的水稻品种对白背飞虱的忌避性、抗生性和耐害性的测定。4个粳稻品种(91-17、丙90-98、丙850和丙93-63对成虫表现出较强的忌避性,丙93-63对白背飞虱产卵具有明显的忌避性。协优9308和春江06对白背飞虱的抗生性最强,协优413对白背飞虱具有一定的抗性。     

Toxic effects of neem-based insecticides on Pieris brassicae (Linn.)

Four neem-based insecticides, Neemix^® (0.25% EC @ 20 mg azadirachtin/liter), Ecozin^® (3% EC @ 20 mg azadirachtin/liter), Agroneem^® (0.15% EC @ 4.8 mg azadirachtin/liter) and Neem oil (0.25% EC azadirachtin @ 20 mg azadirachtin/liter) and a non-commercial neem leaf powder, were evaluated for oviposition deterrence, antifeedant effect to larvae and toxicity to eggs and larvae of Pieris brassicae (Linn.) on cabbage leaves in the laboratory. The concentrations tested were with in the ranges of recommended field rates. Oviposition deterrence in no-choice, two-choice and six-choice assays, was observed for all the treatments. They exhibited significant (P < 0.01) oviposition deterrence on P. brassicae when compared with a non-treated control. Cabbage leaves treated with the neem-based insecticides were used as an egg-laying substrate. Numbers of eggs oviposited by P. brassicae adults on treated cabbage leaves were significantly lower then those treated with water, but no significant differences were detected among the neem insecticides. They also deterred feeding by Pieris larvae and exhibited significant antifeedant effects. Larvae of P. brassicae on treated leaves stopped feeding and dropped from the leaf, resulting in no or minimal damage. Direct contact with neem-based insecticides decreased the survival of eggs. Survival of larvae fed for 9 days on leaves treated with neem-based insecticides was reduced to 51%, 49%, 48%, 24% and 18% in the Neem oil, Neemix, Agroneem, Ecozin and neem leaf powder treatments, respectively. Therefore, it can be concluded from the present investigations that neem-based insecticides had oviposition deterrence, antifeedant and toxic effect to P. brassicae.     

玉米褐斑病适宜侵染时期研究

测定玉米褐斑病的适宜侵染时期及不同叶龄玉米叶片浸提液对褐斑病菌休眠孢子囊萌发的影响。结果表明,不同叶龄玉米感染褐斑病的程度不同,5~7叶期玉米较易感病,其中,5叶期玉米上褐斑病发生最重,郑单958和浚单20病情指数分别为51.1和32.5,显著高于其他叶龄。郑单958和浚单20的玉米叶片浸提液均能提高褐斑病菌休眠孢子囊的萌发率,其中,以第5片叶的浸提液对休眠孢子囊的萌发提高最显著,郑单958和浚单20第5片叶的叶片浸提液分别比对照的萌发率提高15.1%和38.8%。因此,5~7叶期玉米易感褐斑病,玉米褐斑病的最适宜侵染时期为5叶期。     

日本食蚧蚜小蜂的寄生行为观察

日本食蚧蚜小蜂Coccophagus japonicus Compere是橡副珠蜡蚧Parasaissetia nigra Nietner的重要天敌之一。为了明确该蜂的寄生行为及雌蜂体型大小对其产卵的影响,在室内观察其寄生行为及雌蜂不同体型大小条件下的产卵情况。结果表明：日本食蚧蚜小蜂的寄生过程包括搜寻寄主、识别寄主、产卵器刺探、产卵、产卵后处理5个阶段。日本食蚧蚜小蜂的寄生时间、寄生率、平均着卵量随寄生次数增多而增加,寄生次数与卵量吻合率随寄生次数增加而降低;第1次寄生时,寄生所需时间为19.75 s,寄生率为73.12%,寄生次数与卵量吻合率为69.89%,平均着卵量为0.76粒;第3次寄生时,寄生所需时间为24.37 s,寄生率为83.33%,寄生次数与卵量吻合率仅为8.33%,平均着卵量为1.67粒。雌蜂体型大小与其产卵量呈正相关,体长小于等于1.20 mm时,产卵量及寄生率最小,分别为16.83粒和49.4%;1.40 mm<体长≤1.50 mm时产卵量为33.06粒,寄生率72.3%;而体长大于1.50 mm时产卵量达37.5粒,寄生率为72.2%;雌蜂后足胫节长对其产卵及寄生率也有类似影响,说明该蜂扩繁时应选用体型较大的雌蜂。     

不同激素种类及浓度对红厚壳嫩枝扦插育苗的影响

以红厚壳（Calophyllum inophyllum）1年生嫩枝为扦插材料,探讨不同浓度梯度的萘乙酸（NAA）、吲哚丁酸（IBA）及生根粉1号（ABT）对插穗抽叶特性和生根特性的影响,并运用隶属函数值法对各处理组合的扦插效果进行综合评价。结果表明：与对照处理相比,不同激素种类及浓度处理显著影响嫩枝插穗的抽叶率、新叶数量、新叶面积等抽叶特性指标,以及生根率、偏根率、不定根数量、不定根体积、侧根数量和侧根长度等生根特性指标,但对宿叶率影响不显著。不同激素处理下嫩枝插穗的抽叶率和生根率分别为21.7%~66.7%和43.3%~98.3%,而对照处理的抽叶率和生根率均为0。基于隶属函数值法综合分析,激素处理对扦插效果的促进作用依次为NAA>ABT>IBA。NAA处理插穗的抽叶率和生根率均值为62.1%和95.4%,分别比ABT处理增加47.5%和30.2%,比IBA处理增加62.0%和57.9%。综合分析,红厚壳嫩枝扦插的最佳处理组合为1000 mg/L NAA,其抽叶率为61.7%,生根率为95.0%。     

胡麻残茬水提液化感自毒作用研究

为探讨胡麻不同器官残茬的自毒作用,明确残茬根、茎及叶中的主要自毒物质,分别制备水提液,以蒸馏水为对照,设置不同浓度梯度水提液,用于胡麻种子萌发及幼苗生长实验,通过测定发芽势、发芽率、株高及根重等指标确定自毒效应,利用气相色谱-质谱(GC-MS)技术分析胡麻残茬根、茎及叶中的主要自毒物质。结果显示,胡麻残茬根、茎及叶水提液对自身种子萌发和幼苗生长总体上表现为"低促高抑"作用,且存在浓度效应。随着水提液浓度增加,胡麻残茬叶水提液最先到达临界浓度,其次为茎水提液,最后为根水提液。综合效应显示,胡麻不同残茬器官水提液化感自毒作用强弱关系为:残茬叶>残茬茎>残茬根。胡麻残茬根、茎及叶水提液中分别鉴定出8种、21种和14种化合物,主要包括酸类和酯类,含量最多的自毒物质为棕榈酸和邻苯二甲酸二丁酯。胡麻残茬根、茎及叶水提液对种子萌发及幼苗生长具有显著的化感自毒效应,可能是导致胡麻连作障碍的主要原因之一。     

Toxical effect of Peganum harmala L. leaves on the cotton leaf worm, Spodoptera littoralis Boisd and its parasitoids Microplitis rufiventris Kok

The leaf extract and its fractions of Peganum harmala L. have shown pronounced mortal effect, decreased percent pupation and adult emergence of the cotton leaf worm, Spodoptera littoralis Boisd. The third instar larvae fed for two days on treated leaves were more susceptible to plant extract and its ethyl acetate and chloroform fractions. The active lowest concentration (5%) of the leaf fractions of P. harmala showed significant effect on the percentage of emerged adult parasitoids, Microplitis rufiventris Kok. GC/MS analysis showed the major constituent in ethyl acetate fraction was (23S) ethylcholest-5-en-3 beta-ol (28.04%) while those of chloroform fraction were hydroxyfuranocoumarin (Bergaptol) (15.68%), piperidinone (12.08%), thymol (11.82%), phosphoric acid, tributyl ester (9.80%) and trimethyl-nonenol (9.66%). The medicinal plant P. harmala could be carefully applied in integrated pest management due to its strong effect on cotton leaf worm pest.     

印楝素杀虫剂防治甜菜甘蓝夜蛾效果初探

试验结果表明,喷施0.3%绿晶印楝素杀虫剂防治甜菜甘蓝夜蛾防效达74.8%～93.2%,高于速克毙,甜菜根产量提高29.4%。     

High potential of agro-industrial by-products of pomegranate (Punica granatum L.) as the powerful antifungal and antioxidant substances

Microorganisms such as fungi are one of the most important factors that cause oxidative processes during postharvest stage and consequently deterioration of agriculture products would not be unexpected. On the other hand, high antioxidant properties of industrial by-products of pomegranate propose them as powerful antioxidant and antifungal substances. So to investigate the antioxidant and antifungal properties of pomegranate, two independent factorial experiments based on randomized design with 5 replications were conducted. In the first experiment the effect of 3 different parts of pomegranate (peel, seed and leaf) and 2 different kinds of extracts (aqueous and methanolic) with 4 concentrations (0, 500, 1000 and 1500 ppm) were investigated on 3 postharvest fungi (Penicillium italicum, Rhizopus stolonifer and Botrytis cinerea). In the second experiment antioxidant capacity and phenolic content were measured for two different extracts from different parts. Based on the results the methanolic extract showed the highest inhibitory effects on the mycelia growth (IMG) and spore germination (ISG) with 49.82 and 41.25% respectively. On the other hand, peel and seed extracts had more inhibitory effect (IMG and ISG) than leaf extract. The phenolic content of peel extract were also measured 2.8 fold higher than pomegranate leaf extract and antioxidant capacity of peel, seed and leaf extracts of pomegranate were 55.3%, 35.7% and 16.4% respectively. Therefore, it seems that the high percentage of phenolic content in the peel and seed of pomegranate could cause the high antifungal and antioxidant activity of their extracts.     

Experimental Study on Antimicrobial Activity of Silk Fabric Treated with Natural Dye Extract from Neem (<Emphasis Type="Italic">Azadirachta indica</Emphasis>) Leaves

In the present study, a novel eco-friendly production of silk fabrics dyed with different natural dye bath concentrations (40, 80, 120, 160, 200 and 240 g/l) extracted from neem (Azadirachta indica) leaves was developed. The surface morphology of the fabrics was examined by scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy to characterize the chemical structure of the fabrics. The SEM images of the undyed fabric show that the fabric was tightly woven with little porosity between the fibres with dozens of silk threads in orthogonal directions. By increasing the neem concentration, a scale of fine particles grew on the surface of the silk fabrics with little macroscopical defects was demonstrated. The fiber diameters and tightness between filaments were significantly increased. The FTIR displayed that, neem dye does not change the characteristic peaks of the silk fabrics. Also, the evaluation of the antimicrobial activity of the undyed and neem dyed silk fabrics was monitored for Gram positive and Gram negative bacteria in addition to yeasts and fungi by using the agar diffusion method. The comparison between the different dye bath concentrations was based on the inhibition zones obtained after incubation. The antimicrobial activity in leaf extract of neem was estimated in Staphylococcus aureus, Bacillus subtilis and Lactobacillus cereus (Gram positive bacteria); Escherichia coli (Gram negative bacteria); Candida albicans and Candida tropicalis (yeasts); and Aspergillus niger and Fusarium solani (fungi). The results emphasized that, the highest neem dye bath concentration (240 g/l) was found to display good inhibitory effect against the Gram positive and reasonable activity against the Gram negative bacteria. Furthermore, the different dye bath concentrations possess no activities against yeast and fungi. In conclusion, the data reveal that the increase of neem dye concentration does not damage the silk fabric; however, it improves its antimicrobial activity by incorporating with antimicrobial agent. The current study highlighted that using neem leaves had beneficial effect in controlling the pathogenic microbial organisms.