Assessment of synthetic chemicals for disruption of Rhynchophorus ferrugineus response to attractant-baited traps in an urban environment

The red palm weevil (RPW), Rhynchophorus ferrugineus Olivier (Coleoptera, Curculionidae), is one of the most severe pests of ornamental palm species in urban areas of Mediterranean countries. Aiming to discover inhibitory semiochemicals for RPW population management in urban environments, we conducted electroantennographic (EAG) screenings of 17 commercially available synthetic compounds, representing three groups of plant volatiles (isoprenoids, phenyl propanoid derivatives and fatty acid derivatives) known for their repellent effects toward insects. These tests were followed by trap-based screenings of EAG-active menthone, α-pinene and methyl salicylate, singly and in combination, under urban conditions. In EAG bioassays, RPW antennae of both sexes showed positive dose-dependent responses to 13 of the 17 synthetic chemicals with significant differences among them. In field trapping experiments, conducted in the city of Palermo, Italy, from weeks 31 to 38 in 2010 and 2011, α-pinene, tested singly or in combination with methyl salicylate (2010) or menthone (2011), reduced trap catches by about 30% to 40%. Methyl salicylate and menthone alone were inactive. In conclusion, RPW is significantly affected by α-pinene. This isoprenoid is a promising disruptant for semiochemical-based management of this pest. In addition, identification of a large number of EAG-active chemicals could serve as a database for future design of active repellents or attractants of RPW adults.     

Current status of red palm weevil infestation in date palm plantations in Israel

The red palm weevilRhynchophorus ferrugineus (Olivier) (RPW) is the most serious pest of date palms in the Middle East. Weevil infestation was first detected in Israel in the summer of 1999 in date plantations in the Jordan Valley, on the west bank of the Jordan River and in the northern area of the Dead Sea. For 2 years following the discovery of the pest, prophylactic insecticide chemical treatments as well as adult weevil trapping were carried out over 450 ha of date palm plantations. Traps loaded with a commercial aggregation pheromone, ferrugineol, supplemented with ethyl acetate and a fermenting mixture of dates and sugarcane molasses, were posted in high trap density (approx. ten traps per ha) in order to monitor weevil infestation and reduce the RPW population by mass trapping. A significant decrease in number of trapped beetles and infested trees was observed in 2001 and continued in the following years. No infested trees have been found since 2002, indicating a decrease in RPW population. The sex ratio of trapped adults during 3 years of study was significantly female-biased (∼2.5:1). Therefore, mass trapping might have played a significant role in the suppression of RPW populations in date plantations. http://www.phytoparasitica.org posting Dec. 19, 2004.     

The use of sniffing dogs for the detection of Rhynchophorus ferrugineus

The red palm weevil (RPW) Rhynchophorus ferrugineus (Olivier) (Coleoptera: Dryophthoridae) is the most serious pest of Canary Island date palms (Phoenix canariensis Hort. ex Chabaud) and date palms (Phoenix dactylifera L.). Early infestations of this invasive weevil are difficult to detect under field conditions. The adults are very elusive and not visible inside the dense frond of the palms. Efficient methods for detecting this pest are needed for its successful management under field conditions and in particular at ports of entry to avoid its' spreading via infested imported palms. The present study evaluated the ability of Rottweiler and Golden Retriever dogs (Canis familiaris L.) to detect Canary Island palms that were baited with RPW adults or larvae under field conditions. During these experiments, the dogs successfully detected 78% of the baits hidden in the crown of the palms. These encouraging results need to be confirmed by evaluation of the performance of sniffing dogs in detection of naturally infested palms of different species.     

Development of semiochemical attractants for monitoring bean seed beetle, Bruchus rufimanus

BACKGROUND: Bruchus rufimanus is a serious pest of field beans. The objective here was to develop a semiochemical‐baited trapping system to facilitate monitoring of the pest. RESULTS: Volatile compounds that were electrophysiologically active with the antennae of B. rufimanus females were identified from headspace samples of Vicia faba flowers and from male B. rufimanus. Selected headspace samples and synthetic compounds were tested in olfactometer bioassays. The semiochemicals were then formulated in lures for traps and evaluated in a field trapping experiment. Cone traps baited with a three‐component blend of floral volatiles, releasing (R)‐linalool (17.7 mg day^?1), cinnamyl alcohol (0.4 mg day^?1) and cinnamaldehyde (0.77 mg day^?1), caught significantly more of both sexes of B. rufimanus than unbaited control traps. A male volatile, 1‐undecene, was EAG active with female antennae. It was attractive to females in an olfactometer, indicating that it is a sex pheromone. However, in the field it only enhanced trap catches if it was released together with the floral volatiles. CONCLUSION: The blends of semiochemicals identified were shown to be attractive in cone traps under field conditions. The prototype trapping system developed could be used as a monitoring tool to determine infestation levels of B. rufimanus in bean fields. Copyright © 2011 Society of Chemical Industry     

Evaluation of the entomopathogenic fungiMetarhizium anisopliae andBeauveria bassiana against the red palm weevilRhynchophorus ferrugineus

The red palm weevil (RPW,Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) is one of the most severe pests of various palm species, including date palms. While examining the susceptibility of RPW to two entomopathogenic fungi,Metarhizium anisopliae andBeauveria bassiana, strains of the former were found to be more virulent than those of the latter, achieving 100% larval mortality within 6–7 days. The most virulent strains ofM. anisopliae were then tested on RPW eggs and adults. Incubation in a substrate treated withM. anisopliae spores increased egg mortality and reduced their hatchability. The total percentage mortality of eggs and hatched larvae was 80–82%, compared with 34% in the controls. RPW adults were challenged with two types of fungal formulation: dry powder and aqueous suspension. Cumulative adult mortality of 100% was achieved in 2–3 weeks for the dry rice-based formulation and in 4–5 weeks for the spore suspension. As a result of decreased longevity, treated females had a shorter oviposition period and three times lower fertility than the controls. Possible strategies for fungus application are discussed in the light of the high susceptibility of eggs and larvae to fungal infection. http://www.phytoparasitica.org posting July 19, 2006.     

Host plant recognition by two odorant-binding proteins in Rhynchophorus ferrugineus (Coleoptera: Curculionidae)

BACKGROUND

Rhynchophorus ferrugineus, the red palm weevil (RPW), is a key pest that attacks many economically important palm species and that has evolved a sensitive and specific olfactory system to seek palm hosts. Odorant-binding proteins (OBPs) not only play crucial roles in its olfactory perception process but are also important molecular targets for the development of new approaches for pest management.

RESULTS

Analysis of the tissue expression profiles of RferOBP8 and RferOBP11 revealed that these two Rhynchophorus ferrugineus odorant binding proteins (RferOBPs) exhibited high expression in the antennae and showed sexual dimorphism. We analyzed the volatiles of seven host plants by gas chromatography–mass spectrometry and screened 13 potential ligands by molecular docking. The binding affinity of two recombinant OBPs to aggregation pheromones and 13 palm odorants was tested by fluorescence competitive binding assays. The results revealed that eight tested palm volatiles and ferrugineol have high binding affinities with RferOBP8 or RferOBP11. Behavioral trials showed that these eight odor compounds could elicit an attraction response in adult RPW. RNA interference analysis indicated that the reduction in the expression levels of the two RferOBPs led to a decrease in behavioral responses to these volatiles.

CONCLUSION

These results suggest that RferOBP8 and RferOBP11 are involved in mediating the responses of RPW to palm volatiles and to aggregation pheromones and may play important roles in RPW host-seeking. This study also provides a theoretical foundation for the promising application of novel molecular targets in the development of new behavioral interference strategies for RPW management in the future. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Olfactory and visual responses of the longlegged chafer Hoplia spectabilis Medvedev (Coleoptera: Scarabaeidae) in Qinghai Province, China

BACKGROUND: Monitoring traps and control methods are needed for the long‐legged chafer, Hoplia spectabilis Medvedev, which has recently reached outbreak numbers in pastureland of Qinghai Province, China. RESULTS: Field trapping experiments, using cross‐pane funnel (barrier) traps, showed that H. spectabilis adults were not significantly attracted to branches of the host plant Dasiphora fructicosa (L.) Rydb. However, beetles were slightly attracted to similar host plant branches infested by conspecific beetles, possibly owing to weakly attractive volatiles, primarily (Z)‐3‐hexenyl acetate, released from beetle‐damaged host leaves. This compound was weakly attractive when released from traps. However, H. spectabilis beetles showed strong visual responses to yellow‐ or white‐painted trap panes, with weaker responses to blue, red or green panes, and least response to black panes. Black traps at 0.2–1.5 m above ground intercepted significantly more beetles than traps at 2.5 m. The mean flight height based on trap catches was 0.88 m (SD = 0.76), yielding an effective flight layer of 1.9 m. Flight response of beetles to colored barrier traps occurred between 10:00 and 18:00, and peaked between 12:00‐14:00, when daily temperatures reached their maximum. CONCLUSION: Unbaited yellow or white cross‐pane funnel traps are recommended for both monitoring and mass‐trapping programs against this economically and ecologically important scarab beetle. Copyright © 2010 Society of Chemical Industry     

Synthesis of allylic trifluoromethyl ketones and their activity as inhibitors of the sex pheromone of the leopard moth, Zeuzera pyrina L. (Lepidoptera: Cossidae)

BACKGROUND: Trifluoromethyl ketones (TFMKs), structurally related to the pheromones, are good inhibitors of pheromone communication in insects. To determine their activity on Zeuzera pyrina L. (Lepidoptera: Cossidae), a polyphagous pest, the authors have prepared two diunsaturated TFMK analogues of the major (3) and the minor (4) pheromone components, and two monounsaturated ones (5, 6). Their biological activity in electroantennogram (EAG), wind tunnel and field tests is presented. RESULTS: The synthetic strategy to obtain the allylic TFMKs 3 and 5 is based on the reactions of diene 10 and 1‐octadecene with trifluoroacetaldehyde ethyl hemiacetal, followed by Dess–Martin oxidation of the resulting homoallylic trifluoromethyl alcohols. In EAG, topical application of analogues 3 and 4 on male antennae significantly reduced the pheromone response. In the wind tunnel, compound 4 reduced the number of contacts with the pheromone source. In the field, traps baited with mixtures of pheromone and inhibitors captured significantly fewer males than the pheromone alone. CONCLUSION: An efficient synthesis of allylic TFMKs is reported, with good overall yield, regiospecificity and diastereoselectivity. These compounds are good inhibitors of the pheromone in electrophysiology, wind tunnel and field tests. The results show the importance of two unsaturations at positions 2 and 13 of the trifluoroacyl group in the structure of the analogues, the latter being critical for inhibitory activity. Copyright © 2011 Society of Chemical Industry     

铜绿丽金龟对寄主植物挥发物的触角电生理及行为反应

为深入了解铜绿丽金龟的取食行为,探索开发安全高效的植物源引诱剂,应用昆虫触角电位反应仪和Y型嗅觉仪测试其对不同寄主植物挥发物的趋向行为差异,并根据室内行为结果配制诱剂进行大田试验。结果表明:铜绿丽金龟雄虫对水杨酸甲酯和(1,1’-联环戊基)-2-酮的触角电位反应(electroantennography,EAG)值显著高于其它试剂;石竹烯和水杨酸甲酯能引起雌虫触角较强的电位反应;乙酸顺式-3-己烯酯和石竹烯分别对雄虫和雌虫有较高的嗅觉选择反应率,分别达0.95和0.94。综合EAG和嗅觉试验结果,选择对雌、雄虫均有较好引诱效果的反式-2-己烯醛、乙酸顺式-3-己烯酯、石竹烯、(1,1’-联环戊基)-2-酮和水杨酸甲酯进行田间试验,最终筛选到铜绿丽金龟雄虫的最适引诱剂为每诱芯360 mg乙酸顺式-3-己烯酯,雌虫的最适引诱剂为每诱芯360 mg石竹烯,日诱虫量分别可达33.00±1.53头和29.33±1.45头。     

3种寄主挥发物中引起旋幽夜蛾嗅觉反应的活性组分分析

为探究植物挥发物中引起旋幽夜蛾嗅觉电生理反应的活性组分, 本研究采用动态顶空吸附法收集藜、甜菜和棉花植株的挥发物, 利用气相色谱-触角电位联用仪(GC-EAD)和气相色谱-质谱联用仪(GC-MS)定性鉴定寄主挥发物中引起旋幽夜蛾嗅觉反应的活性组分。结果表明, 藜挥发物中有6种活性组分, 甜菜和棉花挥发物中各有5种, 其中乙酸叶醇酯、1, 2-二乙苯、对二乙苯、壬醛、二乙二醇丁醚为3种植物共有的挥发物组分, 异佛尔酮仅在藜挥发物中发现。触角电位(EAG)测定结果显示, 以上6种组分都能引起旋幽夜蛾雌雄成虫的EAG反应, 且随浓度增加EAG相对反应值增大。雌雄成虫对壬醛和异佛尔酮的EAG反应最强烈, 其次是乙酸叶醇酯和1, 2-二乙苯。在相同浓度条件下, 雌雄成虫对同种化合物的EAG反应无性别特异性。本研究为探明旋幽夜蛾定位寄主机制及开发行为调控产品提供基础。     

艾蒿提取物及其不同柱层析馏分对甜菜夜蛾产卵行为的影响

利用Syntech触角电位仪,测定了甜菜夜蛾雌成虫对艾蒿提取物和4种溶剂(苯、乙酸乙酯、丙酮和乙醇)柱层析馏分的触角反应;利用涂纸法,测定了艾蒿提取物和4种馏分对甜菜夜蛾产卵的忌避特性和抑制特性。结果表明:甜菜夜蛾雌成虫对相同浓度(10 mg/mL)提取物和馏分的触角反应存在很大差异,对丙酮馏分的反应最强烈,电位值为9.632±1.054 mV,其次为乙酸乙酯和苯馏分,以乙醇馏分的反应最弱。提取物和不同馏分对甜菜夜蛾的产卵忌避作用存在很大差异,丙酮馏分、乙酸乙酯馏分和提取物都具有一定的忌避作用,而且随浓度上升而增强,其中以丙酮馏分的忌避作用最强,10 mg/mL的忌避率达到49.0%。不同浓度处理时,都以丙酮馏分和乙酸乙酯馏分的产卵抑制作用最强,且随浓度上升而增强,10 mg/mL的抑制率分别达到72.16%和68.95%;较高浓度(5 mg/mL和10 mg/mL)时,提取物、苯馏分和乙醇馏分也具有一定的产卵抑制作用。     

Eradication campaign for Rhynchophorus ferrugineus in Cyprus1

Rhynchohorus ferrugineus (red palm weevil) was first recorded in Cyprus in September 2006 on 4 palm trees (Phoenix canariensis) in a hotel garden in the coastal area of Lemesos. All infested plants from the first point of outbreak were removed and burned. Intensive monitoring showed that R. ferrugineus was present in the areas of Limassol, Larnaca and Paphos. In the Famagusta area a consignment of palm trees was found to be infested and measures for the destruction of the consignment were taken. From the results of monitoring, the areas of Limassol, Larnaca and Paphos were placed under close supervision and infested zones and buffer zones were created. In the area of Famagusta there was no trapping of adult insects, however a demarcated area was created and will remain under close supervision for a period of 3 years. The establishment of demarcated areas was carried out according to the provisions of the EU Decision 2007/365/EC. The measures taken in the infested and buffer zones were mainly the application of chemicals through the crown of the susceptible palm plants and the removal of heavily infested palms. Since burning proved not to be an efficient method, the heavily infested palm plants were buried in approved areas, after chemical spraying. In addition the NPPO, of Cyprus has taken measures in training all plant health inspectors in the identification and handling of infested palm trees and public awareness about R. ferrugineus. Surveys continue throughout Cyprus with the use of pheromone traps and eradication measures continue within the demarcated areas with the aim of eradicating of this pest.     

绿盲蝽对七种锦葵科植物挥发物的EAG和趋向行为反应

研究绿盲蝽Apolygus lucorum(Meyer-Dür)对锦葵科植物挥发物的EAG和趋向行为反应,为研发绿盲蝽引诱剂或驱避剂策略提供科学依据。田间采用动态顶空采样方法收集了7种锦葵科植物的挥发物,通过室内气相-质谱联用系统(GC-MS)进行物质鉴定及定量分析,最终测定了雌、雄绿盲蝽成虫对11种候选特征挥发物的触角电位(EAG)反应和嗅觉趋向选择行为。结果表明,7种锦葵科植物的挥发物种类和含量有较大差异,而且4种棉花品种之间的挥发物差异也很显著。棉花石远321的挥发物总量最大,其中4,8-二甲基-1,3,7-壬三烯(DMNT)含量最高,壬醛和罗勒烯其次。蜀葵的挥发物种类和含量均最少。11种候选特征挥发物均能够引起绿盲蝽雌、雄成虫EAG反应,且雄性成虫的反应值大都高于雌性成虫。其中,绿盲蝽雌、雄成虫触角对反-2-己烯酸丁酯EAG反应值最大,芳樟醇、乙酸叶醇酯、甲基庚烯酮及DMNT也能够激发绿盲蝽较大的EAG反应。在趋向行为检测中发现,DMNT及柠檬烯等对雄性成虫具有吸引作用。对雌性成虫有吸引作用的物质有γ-萜品烯、DMNT、月桂烯、α-石竹烯、罗勒烯及乙酸叶醇酯等,其中γ-萜品烯和乙酸叶醇酯对雌性成虫具有极显著吸引效果。锦葵科候选植物挥发物对绿盲蝽雌、雄虫具有不同EAG和趋向行为反应影响,候选气味化合物可以作为设计绿盲蝽引诱剂组分进行害虫防控田间实践。     

Trapping whiteflies? A comparison of greenhouse whitefly (Trialeurodes vaporariorum) responses to trap crops and yellow sticky traps

BACKGROUND: Greenhouse whiteflies, Trialeurodes vaporariorum (Westwood), are notorious pests that, through the reduction of crop yields and excretion of honeydew, cause significant economic losses for sweet pepper (Capsicum annuum L.) growers. Chemical and biological controls are the two most common forms of whitefly management in greenhouses. Consequently, insecticide resistance and inadequate control have rejuvenated interest in alternative tactics. In the present study, whitefly responses to trap crops (eggplant and squash) and yellow sticky traps were compared in order to identify the most effective traps for dispersing and resident adults. RESULTS: Results indicated that yellow sticky traps were most effective at trapping adult whiteflies. Significantly more dispersing whiteflies were recorded on eggplant than on squash trap crops. None of the traps significantly reduced adult populations on the main crops (peppers) compared with the control. However, yellow sticky traps did significantly reduce oviposition on peppers. CONCLUSIONS: Adult whiteflies were most effectively trapped on yellow sticky traps followed by eggplant trap crops. Further study of whitefly trapping using visual cues may enhance trapping management. Specifically, research combining yellow sticky traps with other control strategies is recommended. Copyright © 2011 Society of Chemical Industry     

Damage by Homalinotus depressus in commercial coconut palm crops in the Amazonian region of Brazil

The coconut palm (Cocos nucifera L., Arecaceae) has great economic and social importance for many industrial and non-industrial products. Pests can reduce its productivity and cause its death. In 2005, larvae and adults of a Curculionidae were observed damaging the floral stalk of coconut palms in commercial plantations in the municipality of Moju, Pará State, in the Brazilian Amazon. Insects were identified as the black coconut bunch weevil, Homalinotus depressus (L.) (Coleoptera: Curculionidae: Cholini). This is the first report of this pest damaging coconut palms in Brazil.     

Disruption of responses to pheromone by (Z)-11-hexadecenyl trifluoromethyl ketone,an analogue of the pheromone,in the cabbage armyworm Mamestra brassicae

The effects of (Z)-11-hexadecenyl trifluoromethyl ketone (Z11-16:TFMK) a fluorinated pheromone analogue, on the responses to sex pheromone of the male cabbage armyworm, Mamestra brassicae, have been investigated in an actograph and by electroantennography (EAG). In spite of its structural proximity with the natural pheromone, Z11-16:TFMK was poorly active in EAG, and not active on male behaviour. When permeated in the air, Z11-16:TFMK reversibly inhibited the electroantennographic responses to (Z)-11-hexadecenyl acetate (Z11-16:Ac), the main component of the sex pheromone. In the actograph, the latency of the activation was increased and the intensity of the behavioural activity of males in response to Z11-16:Ac was significantly reduced in the presence of Z11-16:TFMK. These results, along with others previously reported by us, provide new pointers to the possible use of Z11-16:TFMK in pest-control strategies.     

First report of the nipa palm hispid <Emphasis Type="Italic">Octodonta nipae</Emphasis> on queen palms in Cyprus

In December 2009, numerous adults and larvae of the nipa palm hispid Octodonta nipae (Maulik) (Coleoptera: Chrysomelidae: Cassidinae) were found for the first time on the island of Cyprus, in unopened young leaves of Syagrus romanzoffiana (Cham.) Glassman palm species. All infested palms of this species evinced serious decline with all young leaves showing signs of attack, but the beetles and larvae themselves were found only in fronds from the central shoot.     

Sex pheromone traps for detecting and monitoring the raisin moth,cadra figulilella,in date palm plantations

Field tests were carried out to determine whether pheromone traps, baited with (Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:Ac) impregnated in rubber septa (Maavit, Israel), could provide a reliable tool for monitoring the raisin moth,Cadra figulilella (Gregson), in date palm plantations. No significant differences were detected between captures of males in traps baited with 1 or 10 mg pheromone/dispenser. However, traps baited with 1 mg pheromone captured significantly more males than those baited with 0.1 mg pheromone/dispenser. No differences were found between captures of males in traps hung at a height of 8 m (near the bunches) or 2–3 m (on palm trunks). Two peaks of male capture were detected, one in May-June and the other during September-October (ripening period). Results indicate a positive relationship between captures in traps and infestation levels by larvae. Pheromone traps baited with 1 mg Z9,E12–14:Ac impregnated in rubber septa and hung on palm trunks (at a height of 2–3 m), were very useful for monitoringC. figulilella populations and for determining the accurate timing of insecticide applications.     

Efficiency of the synthetic sex attractant and the effect of trap size on captures ofSpodoptera littoralis males in water traps and in dry funnel traps

The efficiency of the synthetic sex attractant ofS. littoralis and the effect of trap size on male captures in water traps and in newly designed dry traps were investigated. The synthetic attractant was less efficient in attractiveness than virgin females in both small (17 cm) and large (60 cm) traps. Trap size did not affect male captures in traps baited with either virgin females or synthetic pheromone. The dry trap tested was as efficient as the water trap, easier to handle, and highly suitable for monitoring or for mass trapping ofS. littoralis.     

Efficacy of the pear ester as a monitoring tool for codling moth Cydia pomonella (Lepidoptera: Tortricidae) in New Zealand apple orchards

BACKGROUND: The behavioural response of both sexes of codling moth, Cydia pomonella to the pear-derived kairomone (ethyl (2E,4Z)-2,4-decadienoate), codling moth sex pheromone (E,E-8,10-dodecadien-1-ol), and sex pheromone combined with the pear derived kairomone loaded into red rubber septum were investigated in trapping experiments in New Zealand apple orchards. A range of 0.01-10.0 mg of pheromone loading in rubber septum dispensers was tested and the highest catch of males was in traps baited with 1.0 mg. No dose response in trap catch of males was seen in traps baited with different amounts of pear-derived kairomone (0.01-10.0 mg). RESULTS: The number of females caught was significantly affected by the amount of pear derived kairomone used to bait traps, with the highest catch obtained at 10 mg loading. The attractiveness of sex pheromone was not enhanced by the addition of the kairomone either when used in the same bait or in a separate bait. The mean number of males captured in traps was reduced by 44% when the pheromone and kairomone were combined at ratio of 1:1 (0.1 mg pheromone: 0.1 mg kairomone) in separate sources. CONCLUSION: Kairomone baited traps showed some potential for monitoring the flight activity of female C. pomonella in apple orchards in two locations (Canterbury and Hawke's Bay). However, the number of male moths caught was low as compared to the number of male moths caught in pheromone-baited traps, and therefore the sex pheromone should continue to be used for monitoring male activity.