丁香酚对花鲈幼鱼的麻醉效果

为研究丁香酚对花鲈(Lateolabrax maculatus)幼鱼的麻醉效果。采用静水方法在水温(27±1)℃下研究不同质量浓度丁香酚(20、25、30、40、50、60、80 mg/L和100 mg/L)对规格为(21.6±2.75)cm长和(110.3±30.67)g重的花鲈麻醉效果和呼吸频率的影响。25~100 mg/L质量浓度的丁香酚均能使花鲈进入深度麻醉期,且麻醉浓度与平均入麻时间呈负相关,与平均复苏时间成正相关;丁香酚质量浓度为50 mg/L时,麻醉效果较好。低浓度丁香酚20 mg/L对花鲈呼吸频率影响不明显。在质量浓度达到40~100 mg/L时,鱼体由麻醉期(A3)进入深度麻醉期(A4),呼吸频率迅速降低。以50 mg/L丁香酚将花鲈麻醉后再在空气中进行暴露,暴露时间与复苏时间呈正相关。暴露时间在2~30 min范围内的复苏率为100%。当时间增加至35、40和45 min时,复苏率降低至66%,33%和0。且暴露时间大于20 min花鲈只能进入恢复期3期(R3)。因此,50 mg/L的丁香酚麻醉液是花鲈幼鱼的理想麻醉浓度。     

绿豆象在不同豆类上的生长发育及产卵选择性研究*

 在室内25℃恒温条件下,饲养观察了绿豆象［Callosobruchus chinensis（Linn）］对不同豆种的产卵选择性、产卵量、卵的孵化率、幼虫和成虫的生长发育历期。结果表明,供试的17种豆粒上绿豆象的着卵率均达80％以上,且不同豆种粒上产卵量差异显著（P＜0.01）,卵在不同豆种上的孵化率间也存在显著差异（P＜0.05）,卵孵化后,幼虫仅在蚕豆、绿豆、红皮豇豆、豌豆、黑豆、红小豆、大豆上可蛀入危害,蛀孔数分别为3.00±0.25,2.00±0.18,3.50±0.09,2.50±0.21,4.50±0.10,2.00±0.22,2.50±0.17蛀孔/豆,差异显著（P＜0.05）。在蚕豆、绿豆、红小豆、红皮豇豆、黑豆、大豆粒上的世代存活率分别为(0.63±0.12)%,(54.84±0.09)%,(44.40±0.08)%,(46.33±0.11)%,(66.88±0.10)%,(45.71±0.11)%,(21.59±0.21)%;雌虫的产卵期分别为(4.24±1.58)d,(5.10±0.22)d,(5.40±0.26)d,(5.21±1.25)d,(5.30±0.38)d,(4.63±0.41)d和(4.30±0.80)d,差异不显著（P＞0.05）,卵历期分别为(5.01±0.15)d,(4.30±0.05)d,(4.10±0.08)d,(5.10±0.18)d,(4.30±0.07)d,(4.20±0.14)d及(4.51±0.16)d,差异不显著（P＞0.05）;幼虫的平均历期分别为(33.40±4.85)d,(31.60±1.78)d,(28.22±3.56)d,(30.91±2.49)d,(27.30±1.98)d,(29.50±1.93)d及(36.70±4.97)d,差异显著（P＜0.05）。不同豆种上绿豆象雄虫寿命间差异不显著（P＞0.05）,而雌虫寿命差异显著（P＞0.05）。     

高温处理对绿豆象不同虫态的致死效果

为明确绿豆象最耐受高温的虫态,获得该虫态完全防控温度和时间,为防治仓储绿豆象提供理论支撑。试验选择35℃、45℃、55℃3个温度对绿豆象的卵、幼虫、蛹、成虫分别处理30min、60min、90min、120min、150min、180min,测定不同温度条件不同处理时间后绿豆象各虫态的死亡率。结果显示：4种虫态中耐热性最强的虫态为绿豆象蛹期,绿豆象蛹期经55℃处理150min后,其死亡率达100%。因此,利用高温方法防治仓储绿豆象是可行的。     

抗虫绿豆对绿豆象生长发育及体内几种酶活性的影响

为明确抗虫绿豆对绿豆象Callosobruchus chinensis L.生长发育的抑制作用,采用室内人工接虫和生化测定的方法,研究了绿豆象幼虫取食抗虫绿豆后其体重、体内消化酶、保护酶和解毒酶活性及成虫羽化率和体重的变化。结果表明,取食抗虫绿豆的绿豆象幼虫体重、雌、雄成虫体重以及成虫羽化率分别是取食感虫绿豆的0.69、0.69、0.71及0.14倍;取食抗虫绿豆8~16 d的绿豆象幼虫中肠总蛋白酶、α-淀粉酶和α-葡萄糖苷酶活性均显著低于对照;保护酶超氧化物歧化酶、过氧化物酶和过氧化氢酶与解毒酶羧酸酯酶和谷胱甘肽转移酶的活性在绿豆象幼虫取食8~12 d时均显著高于对照,但取食14~16 d时,2种解毒酶活性与对照差异不显著。表明抗虫绿豆可抑制绿豆象幼虫中肠消化酶活性,影响其体内保护酶和解毒酶活性,从而使绿豆象幼虫不能正常生长发育。     

小豆田间绿豆象卵空间分布型

绿豆象是小豆的主要仓贮害虫。笔者对北京地区夏播小豆田进行实地取样调查,发现绿豆象在小豆鼓粒初期已将卵产到豆荚上,9月上、中旬为产卵高峰期,并逐渐发育成幼虫侵入豆粒中。绿豆象卵在小豆荚上的空间分布型为聚集分布,其聚集原因是由于环境因素引起的。9月10日─9月15日是控制田间绿豆象产卵及卵发育的较好时机。     

灰豆象生物学研究初报

本文就灰豆象生物学进行了试验研究。以白扁豆为饲料饲料观察结果，灰豆象在温州市室内条件下每年发生6代。以幼虫在豆粒内越冬，越冬幼虫于翌年5月上旬羽化为成虫。灰虫象危害各种扁豆、各种豇豆、蚕豆、绿豆、赤豆、大豆等。以嗜食的白扁豆作饲料，饲养2－3月，繁殖倍数分别为62．7与108．7倍；饲养3个月的饲料损失率为55．58％。     

Effect of storage on the efficacy of powdered leaves ofAnnona squamosa for the control ofCallosobruchus maculatus on cowpeas(Vigna unguiculata)

Annona squamosa L. is widespread in Sri Lanka and its leaves are collected by some farmers to protect their stored cowpeas from predation by bruchids. Removal of the leaves during the dry season, when the fanners harvest their cowpeas, can decrease the yield ofA. squamosa fruit. This study investigated whether storing the leaves before they are used would reduce the insecticidal activity of the leaves. Overall, acetone and ethanol extracts made from fresh and stored leaves ofA. squamosa decreased the number of adultCallosobruchus maculatus (F.) emerging from cowpeas; however, in some bioassays the extracts from fresh leaves were more active than those from leaves stored for 6 months. Acetone extracts from fresh and stored leaves were toxic to adult beetles, whereas the ethanol extracts were not active. Acetone and ethanol extracts from fresh leaves had potent ovicidal activity when applied to 2-day-old eggs.     

Isolation of a novel Carica papaya α-amylase inhibitor with deleterious activity toward Callosobruchus maculatus

Cowpea (Vigna unguiculata) is a subsistence crop for small and poor farmers from Latin America and Africa. This culture is commonly damaged by cowpea weevil (Callosobruchus maculatus), which burrow into stored seeds to fed on. Due to impact of larval predation, several plant defense studies have been developed, indicating that α-amylase inhibitors are able to impede and/or reduce bruchids digestive process. In this report, a novel α-amylase inhibitor from papaya seeds (Carica papaya) with activity against cowpea weevil enzymes was purified and biochemical characterized. Peeled seeds were macerated and extracted with a 0.6 M NaCl and 0.1% HCl solution. Crude extract was precipitated with ammonium sulphate (100%). After dialyses, this rich fraction was applied onto a CM-Cellulose column and retained peak was submitted to an analytic reversed-phase column HPLC (Vydac C-18TP) yielding several peaks. Only one fraction, with molecular mass of 4562 Da, showed significant inhibitory activity against C. maculatus α-amylases. Otherwise, no inhibitory activities against mammalian α-amylases were observed. Bioassays using artificial seeds containing C. papaya α-amylase inhibitor rich fraction (0.5% and 1.0%) were also conduced showing that α-amylase inhibitors were able to increase larval mortality (50%) and also decrease insect fecundity and adult longevity. These results showed the presence of an α-amylase inhibitor from C. papaya seeds with high specificity to insect enzymes, indicating that this inhibitor probably could be used, through genetic engineering, in the construction of transgenic plants with enhanced resistance toward cowpea weevil.     

Efficacy of Artocarpus altilis (Parkinson) Fosberg extracts on contact mortality,repellency, oviposition deterrency and fumigant toxicity of Callosobruchus maculatus (F.) (Coleoptera:Bruchidae)

Callosobruchus maculatus (F.), a major pest of grain legumes, causes considerable losses worldwide. C. maculatus management relies on synthetic insecticides with their adverse environmental and health concerns. The current study investigated the use of Artocarpus altilis (breadfruit) extracts on contact and fumigant toxicity, repellency and oviposition deterrency of C. maculatus as a management strategy. Fumigant mortality (LC₅₀) of the dry inflorescence extract of A. altilis was 126.65 µL L^?1 air at 53.4 h. Fruit extract gave 73.3% repellency at 1000 ppm after 24 h. Percent repellency was dose and time dependent. Green inflorescence extract of A. altilis reduced egg laying with 50% oviposition occurring after 37.78 h at 1000 ppm. We conclude that extracts of leaf, fruit, green and dried inflorescence of A. altilis displayed contact mortality, repellency, deterred oviposition and had fumigant activity toward C. maculatus.