锈赤扁谷盗食物源引诱剂筛选及作用机制分析

本文评估了不同食物组合对锈赤扁谷盗的诱虫效果,并分析了不同温度、虫口密度、食物挥发物等因素对引诱剂诱虫效果的影响。结果表明：在室内和实仓,食物组合5和17对锈赤扁谷盗都具有较好的引诱效果。食物组合5在20~30 ℃下随温度增高诱虫活性升高,30 ℃时具最高诱虫活性26.39%;2.5~15头/kg虫口密度下诱虫率为22.22%~51.85%。食物组合17在实仓中最大诱虫率为75.56%,最长持效期可达40 d。食物挥发物在食物组合诱虫中起重要作用,食物组合5挥发物诱虫率为对照诱芯的2.20倍;锈赤扁谷盗触角对食物组合5挥发物的1~100倍稀释液均有明显的电生理活性。本研究筛选出2个锈赤扁谷盗食物源引诱剂,有望用于粮仓等锈赤扁谷盗的种群动态监测和绿色防控。     

低氧对锈赤扁谷盗生长发育的影响

研究了不同低氧环境对锈赤扁谷盗生长发育的影响,结果表明,10%的低氧环境能够显著延长锈赤扁谷盗的发育历期,并有效抑制卵的孵化、幼虫的蛹化和蛹的羽化。5%的低氧环境则能完全抑制锈赤扁谷盗的生长发育。     

6种主要储粮害虫成虫的耐饥饿能力研究

研究了不同饥饿条件下6种重要储粮害虫赤拟谷盗、锯谷盗、锈赤扁谷盗、米象、谷蠹和烟草甲成虫的耐饥饿能力。研究结果表明,对于羽化后1周龄的6种储粮害虫成虫,赤拟谷盗和烟草甲成虫耐饥饿能力较强,耐饥饿时间可达到30 d以上,其次为锯谷盗、锈赤扁谷盗和谷蠹成虫,耐饥饿时间可达到15 d以上,米象成虫耐饥性最弱,7 d后死亡率即达到100%。食物气味对参试成虫的耐饥饿能力具有一定影响,其影响作用大小与储粮害虫种类有关。锈赤扁谷盗成虫的耐饥饿能力受食物气味影响最大,有食物气味存在时其存活时间可以延长7 d。本研究结果对科学实施储粮害虫综合治理具有重要意义。     

氮气气调胁迫对锈赤扁谷盗种群适合度的影响

为了解不同氮气浓度处理对锈赤扁谷盗Cryptolestes ferrugineus (Stephens)种群适合度的影响,本研究采用构建生命表的方法,研究了95%和98%两种氮气浓度胁迫24 h后锈赤扁谷盗试验种群的生长发育情况,并以此分析了不同氮气浓度对锈赤扁谷盗各生命参数和种群适合度的影响。结果显示,与对照组相比：95%氮气浓度处理后,子代锈赤扁谷盗的孵化率、化蛹率、羽化率均呈现下降的趋势,分别下降了2.00%、11.34%、8.80%,卵、幼虫、蛹及总发育历期分别延长了0.2 d、2.0 d、0.4 d、2.6 d：98%氮气浓度处理后,子代锈赤扁谷盗的孵化率、化蛹率、羽化率均呈现下降的趋势,分别下降了6.00%、25.33%、13.51%,卵、幼虫、蛹及总发育历期分别延长了0.4 d、4.3 d、1.0 d、5.8 d。此外,氮气气调胁迫导致处理当代锈赤扁谷盗单雌产卵量显著减少,子代雌虫占比升高,但子代单雌产卵量未受到影响。本研究分析了氮气气调胁迫对锈赤扁谷盗种群适合度的影响,为氮气气调防治储藏物害虫提供了参考依据。     

食物引诱剂对储粮害虫最佳引诱条件的研究

食物引诱剂具有诱虫谱广,原料来源丰富、价格低等优点,它们不仅能吸引各种储粮害虫两性成虫,而且能吸引其幼虫.研究食物引诱剂对储粮害虫的最佳引诱条件不仅可以为食物引诱剂的开发利用提供理论基础,而且还将食物引诱剂和害虫信息素联合使用,增强信息素引诱害虫的效果.本研究在实验室内比较了碎麦、麦胚、燕麦片、碎花生、花生油、葵花子油、玉米油对赤拟谷盗、锈赤扁谷盗、玉米象、谷蠹、书虱的引诱活性.结果表明碎麦、麦胚对5种害虫都有显著的引诱作用,燕麦片对锈赤扁谷盗和谷蠹有明显的引诱活性,而精练葵花籽油对多数害虫呈负趋性.碎麦诱捕器在不同虫口密度下诱捕效果明显不同.诱捕器的4个摆放位置对诱捕赤拟谷盗、锈赤扁谷盗、玉米象、谷蠹、书虱的影响差异显著,并呈一致变化,诱捕顺序为：西南＞东南＞西北＞东北,多重比较显示其中东南方位与西北方位差别不显著,其它方位差异显著.     

黄色花蝽对几种3龄储藏物害虫捕食功能反应及捕食偏好性研究

为保证国家粮食安全,寻找有效的储粮害虫生物防治的方法,本文研究了黄色花蝽Xylocoris flavipes Reuter雌成虫对3龄的赤拟谷盗Tribolium castaneum Herbst、锈赤扁谷盗Cryptolestes ferrugineus Stephens、锯谷盗Oryzaephilus surinamensis Linnaeus、嗜卷书虱Li poscelis bostrychophila Badonnel的防控能力,在室内条件下研究了黄色花蝽对以上几种储粮害虫的3龄幼虫的捕食功能反应方程,以及对以上储粮害虫寻找效应、种内干扰反应和对不同猎物的捕食偏好。结果表明:黄色花蝽雌成虫对3龄的赤拟谷盗、锈赤扁谷盗、锯谷盗、嗜卷书虱的捕食功能反应方程均符合HollingⅡ圆盘方程。根据方程拟合发现黄色花蝽对3龄嗜卷书虱日捕食量最大,最大为44.6头/d。黄色花蝽对各种害虫的寻找效应均随着猎物密度的增大而减小。当猎物的密度达到一定数量后,随着黄色花蝽数量的增多,捕食猎物的平均捕食率随之下降。通过比较黄色花蝽对不同害虫的捕食偏好性Cain指数,结果表明黄色花蝽更偏好捕食锯谷盗和锈赤扁谷盗。     

掌叶苹婆种子提取物对三种主要储粮害虫的毒力测定

采用索氏提取法,以丙酮作为有机溶剂制备掌叶苹婆种子提取物,并利用滤纸药膜法研究了掌叶苹婆种子提取物对玉米象、谷蠹和锈赤扁谷盗3种试虫成虫的触杀作用。结果表明,掌叶苹婆种子丙酮提取物对玉米象、谷蠹和锈赤扁谷盗3种试虫成虫具有很强的触杀作用,且触杀作用随着处理时间延长和处理剂量增加而显著增强。在浓度3.923 mg/cm2处理剂量下处理96 h后提取物对3种试虫的触杀作用校正死亡率均达到100%。掌叶苹婆种子丙酮提取物对玉米象、谷蠹和锈赤扁谷盗成虫的触杀毒力LD50值分别为:0.875、0.716和1.389 mg/cm2。3种试虫成虫对提取物的敏感性为谷蠹>玉米象>锈赤扁谷盗。     

极端温度对三种扁谷盗属储粮害虫的致死作用

分析了42～62 ℃的极端高温、10～25 ℃的常规温度和-5～-15 ℃的极端低温对三种扁谷盗属害虫的致死作用,研究了极端低温下锈赤扁谷盗、长角扁谷盗和土耳其扁谷盗对温度的敏感差异性,评估了控温储粮技术防治扁谷盗害虫的可行性。在极端高温下, 54 ℃处理75 min、58 ℃处理60 min、62 ℃处理45 min能够完全杀灭锈赤扁谷盗成虫。在常规温度下,锈赤扁谷盗幼虫12 d死亡率低于30%,其死亡数量随时间的延长而增大。在极端低温下,长角扁谷盗对极端低温较为敏感,其次为土耳其扁谷盗、锈赤扁谷盗。极端温度防治害虫的有效性取决于有效的温度、足够的暴漏时间和处理物料的安全性。极端低温通常比极端高温需要更长的暴露时间,但长时间暴露在极端温度下被处理商品受损的风险将进一步增大。     

惰性粉处理稻谷防治锈赤扁谷盗的效果研究

研究了经食品级惰性粉处理的稻谷中锈赤扁谷盗的生存时间,并在实仓验证了散装稻谷仓粮堆表层应用惰性粉拌粮的防治效果。用纯惰性粉处理锈赤扁谷盗的生存时间为0.8 d,采用150 mg/kg惰性粉拌粮法处理的稻谷中锈赤扁谷盗生存时间为0.9 d;无惰性粉处理的活虫样和稻谷样中锈赤扁谷盗的生存时间分别为13.3 d和18.6d。研究表明,惰性粉拌粮对锈赤扁谷盗有显著的防治效果,实仓试验中应用惰性粉可以减少锈赤扁谷盗的数量,但其应用技术有待进一步研究。     

紫光灯对储粮害虫引诱效果的评价

为探讨紫光灯对储粮害虫的引诱作用,本文在试验室内测试了2种紫光灯对赤拟谷盗、杂拟谷盗和印度谷螟的引诱效果。结果显示,自第12～60h起,白色、黑色紫光灯对赤拟谷盗、杂拟谷盗和印度谷螟的引诱数量均超过对照区的虫数,并且至试验结束时紫光灯的引诱数量持续增加。通过对比5d的总诱捕率发现,白色紫光灯引诱印度谷螟的数量显著高于赤拟谷盗、杂拟谷盗的数量,而黑色紫光灯对害虫引诱活性的排序为印度谷螟〉赤拟谷盗〉杂拟谷盗;黑色紫光灯对赤拟谷盗和印度谷螟的引诱活性高于白色紫光灯,而白色紫光灯对杂拟谷盗的引诱活性高于黑色紫光灯。     

Effects of developmental stage,cold acclimation and diet on the cold tolerance of three species of Cryptolestes (Coleoptera: Laemophloeidae)

Flat grain beetles (Coleoptera: Laemophloeidae) are common stored-product insect pests in Canada, infesting cereals in grain bins, equipment and end products in flour mills. We studied the cold tolerance of the three most common flat grain beetles: Cryptolestes ferrugineus, Cryptolestes turcicus and Cryptolestes pusillus, by measuring the survival at −10 °C and supercooling point (SCP) for different life stages (egg, young larva, old larva, pupa and adult) reared on flour mixed with brewer’s yeast. Probit analysis was used to estimate the lethal time for 50 and 95% mortality. This was done with non-acclimated individuals (only held at 30 °C) or cold-acclimated individuals (held at 18, 10 and 5 °C, for 1 week/temperature). In general, adults were the most cold-hardy stage for each of the species. Acclimated insects were anywhere from no increase in cold tolerance to 14-fold more cold-tolerant than the corresponding non-acclimated stage and species. Cryptolestes ferrugineus was most cold-tolerant species (58 d at −10 °C to reach 95% mortality for acclimated adult), C. turcicus was the next most cold-tolerant, (39 d) and C. pusillus was the least cold-tolerant (11 d). The cold tolerance of adults reared on three diets was measured both for acclimated and non-acclimated insects. The adults reared on grain diet (whole wheat kernels, cracked wheat kernels and wheat germ (90:5:5 mass ratio) were the most cold-tolerant, adults reared on white-wheat flour and brewer’s yeast diet (95:5 mass ratio) had the next highest cold tolerance followed by the adults reared on 100% white-wheat flour. Supercooling point (SCP) of insects ranged from −20.6 to −26.7 °C. In general, acclimated insects had slightly lower SCP than non-acclimated insects.     

Immigration of insects into bins storing newly harvested wheat on 12 Kansas farms

Adult insects entering 34 bins (36-238 t capacity) storing newly harvested hard red winter wheat on 12 farms in Kansas were sampled from July through December 1998 using ventilation traps. Insects moving through the grain stored in these bins were sampled using probe traps. During the fourth week of storage, probe traps captured Cryptolestes ferrugineus in all bins, Ahasverus advena in 32 bins, Typhaea stercorea in 31 bins, and Rhyzopertha dominica in 13 bins. Means+/-SE of 5.6+/-0.7 C. ferrugineus, 0.5+/-0.2 R. dominica, 3.5+/-0.3 A. advena, and 3.5+/-0.7T. stercorea were caught per day in probe traps. Ventilation traps provided a more direct measure than probe traps of the total numbers of insects entering bins storing newly harvested wheat. Immigration of A. advena and T. stercorea increased more than that of other species during the storage period, exceeding that of C. ferrugineus and R. dominica during some weeks. Rhyzopertha dominica had the lowest immigration rate. Bin size did not influence ventilation trap catch but as many as a third more insects may immigrate into large bins at the eaves compared with small bins because of their larger circumference. The mean numbers of C. ferrugineus, R. dominica, A. advena and T. stercorea captured in ventilation traps at the bin cap were 7.8, 2.7, 15.1 and 18.3 times, respectively, those captured in ventilation traps at the bin eaves. The estimated means+/-SE for total numbers of insects entering a bin each day were 13.6+/-4.2 C. ferrugineus, 6.3+/-4.7 R. dominica, 5.8+/-1.4 A. advena, and 21.9+/-8.2T. stercorea. Estimates of immigration rates can improve the accuracy with which insect densities are predicted using insect population growth models, and allow computer models to be used more effectively in managing insect pests. Insect infestations may be reduced by screening the openings between the bin cap and the roof, or the roof and the side walls.     

大黑粉盗与赤拟谷盗和锈赤扁谷盗对磷化氢的耐受力比较研究

潜在危害的储粮害虫大黑粉盗Cynaeus angustus研究缺乏,掌握其磷化氢耐受力有助于科学治理。采用快速击倒和FAO推荐方法测定了磷化氢对大黑粉盗的KT50值和毒力方程,并与赤拟谷盗Tribolium castaneum和锈赤扁谷盗Cryptolestes ferrugineus进行了比较,测定了100、200、300、400、500 mL/m3磷化氢模拟熏蒸中3种害虫卵、幼虫、蛹和成虫不同时间的死亡率。磷化氢对大黑粉盗、赤拟谷盗和锈赤扁谷盗的KT50值分别为7、127和3 736 min,相应毒力方程斜率值b为3.67、8.28和9.94,相应LC50值为0.008、1.34和5.88 mg/L。害虫不同虫态在100~500 mL/m3浓度下的半数致死时间LT50值于大黑粉盗卵为4~2 h、幼虫4~1 h、蛹4~1 h、成虫3~1 h,于赤拟谷盗为卵12~5 d、幼虫11~5 d、蛹13~7 d、成虫10~4 d,于锈赤扁谷盗为卵28~13 d、幼虫为18～9 d,蛹26～11 d,成虫17~9 d。相应的完全致死时间（LT100）于大黑粉盗卵为21~6 h、幼虫8~3 h、蛹9~6 h、成虫5~3 h,于赤拟谷盗卵为21~18 d、幼虫21~15 d、蛹27~18 d、成虫21~12 d,于锈赤扁谷盗卵为54~30 d、幼虫42~30 d、蛹48~30 d、成虫36~25 d。所测大黑粉盗为磷化氢敏感品系,其各虫态对磷化氢的耐受力为卵>蛹>幼虫>成虫,其耐受力远小于赤拟谷盗和锈赤扁谷盗磷化氢抗性品系。     

The development of several species of Dermestes (Coleoptera: Dermestidae) on various vegetable foodstuffs

Over a range of vegetable foodstuffs certain species of Dermestes consistently developed more successfully than did others. Least successful were D. frischii larvae which died when small on whole wheat flour, groundnuts and wheatgerm. D. maculatus larvae also died when small on cocoa beans, copra, almonds, whole wheat flour and groundnuts but some reached medium size on wheatgerm. Larvae of D. haemorrhoidalis and D. peruvianus grew up to medium size on whole wheat flour and groundnuts; development was completed on wheatgerm but the final metamorphosis was incomplete or the adults produced were deformed. Up to large larvae of D. ater were produced on whole wheat flour and groundnuts and some morphologically normal adults emerged on wheatgerm. D. lardarius, the most successful species, failed to grow beyond medium size on cocoa beans, copra and almonds but large larvae were produced on whole wheat flour and morphologically normal adults on groundnuts and wheatgerm. These D. lardarius adults from wheatgerm produced a second generation which took longer to develop than the first and produced mainly deformed adults. On a diet of soy flour (60% by weight), wheatgerm (33%) and yeast (7%) adults of all species except D. frischii were produced. Experiments were carried out using isolated larvae at 25°C, 65% r.h. The results are discussed in relation to the sterol content of the foods and the sterol requirements of the species.     

The suitability of dried fruits, almonds and carobs for the development of Ephestia figulilella Gregson, E. calidella (Guenee) and E. cautella (Walker) (Lepidoptera: Phycitidae)

In experiments at 30°C, 70% r.h. and a light régime of 16 hr light/8 hr dark 30 freshly-hatched larvae were placed singly on ripe carob pods obtained direct from Cyprus, and almonds, dates and raisins bought from a shop. The raisins had been treated commercially with paraffin oil prior to export. All 3 species thrived on ground carobs and dates. Between 17 and 26 individuals of each of these species completed development and emerged as adults on these foods. The particle size of carobs had a considerable influence, for only 13 E. calidella and 8 of each of E. figulilella and E. cautella completed development on carob pieces. Only 1 adult of E. calidella was bred from almonds, and 2 from raisins; 9 adults of E. figulilella were bred from almonds, and 16 from raisins, whilst E. cautella gave 17 adults on almonds and 3 adults on raisins.

The shortest mean developmental period for E. figulilella was 34 days on ground carobs, for E. calidella it was 37 days on carob pieces and for E. cautella 35 days on almonds. The longest mean developmental periods were 56 days for E. figulilella and 59 days for E. calidella, both on almonds, and 84 days for E. cautella on raisins.

The significance of these laboratory results in relation to field and warehouse observations is discussed.     

Weight loss caused by development of Sitophilus zeamais Motsch. in maize

Seventy single maize kernels were exposed to oviposition by Sitophilus zeamais. Weevils developed in 50 kernels, 16 yielding one adult, 24 two, 7 three, 2 four and 1 five adults. Weight loss of the kernels was observed throughout the developmental period, at 27°C 70% r.h. Development took a mean of 37 days resulting in adults with a mean weight of 3.1 mg. The overall mean loss in weight per grain was 18.3% or 52.1 mg and on average 2.0 insects emerged per kernel. The total consumption by an insect was 35.1 mg in grains with one emerging adult and approximately 25 mg for those with more than one. Half the total loss occurred between 13–24 days. An estimate of percentage weight loss was obtained by multiplying the percentage of damaged kernels by 0.12, 0.18 or 0.29 for kernels with 1, 2 or 3 emergence holes respectively. Frass weight was found to be of no use in estimating weight loss.     

Deep-fried flavor: characteristics,formation mechanisms,and influencing factors

Abstract

Deep-fried flavor, involving fatty, sweet, burnt, and grilled odors, is an important factor leading to the popularity of deep-fried foods. Comparing with flavors from other conventional and innovative thermal treatments, deep-fried flavor is characterized by a rich variety of volatile species (e.g. aldehydes, alcohols, ketones, hydrocarbons, carboxylic acids, furans, pyrazines, and pyridines), intricate formation mechanisms, and a stronger attraction to consumers. By means of comprehensively literature research, this article critically reviews deep-fried flavor deriving from lipid oxidation, Maillard reaction, hydrolysis and amino acid degradation, with a special emphasis to discuss the involvement of lipid oxidation products in the Maillard pathway to form fried volatiles via secondary processes (e.g. fragmentation, rearrangement, and degradation). The reactions are interacted and influenced by various factors, such as frying oils (e.g. fatty acid composition and oil type), food components (e.g. amino acid and sugar), frying conditions (e.g. oxygen concentration, frying time, temperature, pH, and moisture content), and frying types (e.g. vacuum frying and air frying). Overall, well understanding of chemistry origins of deep-fried volatiles is meaningful to economically manipulate the frying process, optimize the fried flavor, and improve the safety and consumer acceptance of deep-fried foods.     

The impact of grain quantity on the biology of Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae): oviposition, distribution of eggs, adult emergence, body weight and sex ratio

Studies were conducted to observe the effect of grain quantity on the oviposition, distribution of eggs, adult emergence, adult body weight and sex ratio of Sitophilus zeamais, an important pest of maize. Three quantities of maize grains (200, 400 and 800 grains/glass jar of 1 l) were used under laboratory conditions (30°C and 70% r.h.). Twenty five male/female pairs of maize weevil were introduced into each glass jar for 12 d. The greatest and lowest number of eggs was laid on batches of 800 and 200 grain kernels, respectively. The total number of grains attacked followed a similar trend. The aggregation of eggs expressed as a ratio of the variance to mean increased as the amount of maize grains was increased. The aggregation parameter k ranged from 2.35 on 200 grains to 4.49 on 800 grains. On average, a significantly higher proportion of grains were infested (90%) when less grain was present. Emergence of adult weevils was, however, maximal (472 individuals/glass jar) when the grain quantity was highest. The mean weight of the emerged adults was not significantly influenced by grain quantity, but female weevils were heavier than males (mean weight 3.16 vs. 3.05 mg) irrespective of maize quantity and eggs laid. Sex ratio (males/100 females) of emerged adults did not differ among treatments. The importance of grain quantity, and of oviposition, in internally feeding granivores and the possibility that there is an adaptive reproductive strategy are discussed.