Field response of two cetoniin chafers (Coleoptera, scarabaeidae) to floral compounds in ternary and binary combinations

Several synthetic floral lures have been described for the cetoniin scarabs Cetonia aurata aurata L. and Potosia cuprea Fabr. (Coleoptera, Scarabaeidae), exploiting their olfaction-guided behavioural preference for a wide range of flower volatiles. A ternary mixture of 3-methyl eugenol, 1-phenylethanol and (E)-anethol has previously been described as a powerful synthetic floral attractant for both C. a. aurata and P. cuprea. The first objective of the present research was to test whether isoeugenol and eugenol, with a very similar molecular structure to 3-methyl eugenol, can substitute 3-methyl eugenol in the ternary blend. All baited traps caught significantly more of both species than unbaited control traps, however, traps containing 3-methyl eugenol caught significantly more than those with either isoeugenol or eugenol. This indicates a fine tuning in behavioural response to 3-methyl eugenol. The second objective was to devise simpler attractant combinations for C. a. aurata and P. cuprea, based on previous field studies with synthetic floral compounds. Both C. a. aurata and P. cuprea showed strong attraction to the combination of 2-phenylethanol and 4-methoxyphenethyl alcohol, while the combination of 2-phenylethanol and 1,2,4-trimethoxybenzene resulted in medium-size catches, however, mostly catching P. cuprea. This level of selectivity may lead to the development of more selective lures for P. cuprea, and provide a better understanding of the feeding-related olfactory ecology of the two important pest chafer species

Catches of Euxoa tritici in pheromone traps for Anarsia lineatella are due to the presence of (Z)-5-decenyl acetate as an impurity

Traps baited with the synthetic pheromone of Anarsia lineatella Zeller (Lepidoptera: Gelechiidae) frequently captured also Euxoa tritici L. males (Lepidoptera: Noctuidae) in field tests in Hungary. As (E)-monounsaturated compounds are uncommon among sex attractants or pheromone components of Noctuidae, it was hypothesized that the Euxoa catches may have been due to impurities of the (Z) isomer in synthetic (E)-5-decenyl acetate, which is the major component in the pheromone lure of A. lineatella. Traps baited with synthetic (Z)-5-decenyl acetate captured large numbers of E. tritici, and the compound showed a clear dose–response effect. Reanalysis of the synthetic batch of (E)-5-decenyl acetate used in preparation of the A. lineatella lure showed the presence of 10% of the (Z) isomer. Traps baited with synthetic (Z)-5-decenyl acetate can be used in the future for detection and monitoring purposes of E. tritici, a widely distributed pest of cereals and other field crops. The compound also showed attraction of Euxoa seliginis Duponche

In search of co-attractants for cetoniin scarabs (Coleoptera: Scarabaeidae, Cetoniinae): Identification and preliminary field evaluation of volatiles from fermenting apple

When applied in funnel traps, the known three-component floral lure of Cetonia a. aurata and Potosia cuprea attracts large numbers of beetles. Further increasing the attractive power of these traps offers the opportunity to develop a more potent mass-trapping tool that directly reduces local scarab populations and, hence, fruit damage. The current study was initiated by the observation of adult beetles aggregating and feeding in large numbers on ripening fruit, accompanied by the presence of fermentation volatiles detectable by the human nose. Addition of apple pieces to the ternary C. aurata aurata / P. cuprea lure resulted in increased catches, but only in traps where the apple fermented as a result of beetle feeding. Volatile extracts collected from fermenting apple were subjected to GC-EAG, and bioactive peaks were identified as 1-hexanol, acetic acid, n-butyric acid, isovaleric acid, hexanoic acid and 3-methylphenol by GC-MS and GC peak enhancement. In preliminary field trials, a synthetic mixture of all identified compounds reduced activity of the ternary lure, indicating that some were inhibitory. As certain individual compounds or their particular combinations enhanced activity of the ternary lure only numerically, further experiments are discussed to optimize a synergistic blend of fruit fermentation and/or beetle-derived volatiles

The Optimal Choice of Trap Type for the Recently Spreading Jewel Beetle Pests Lamprodila festiva and Agrilus sinuatus (Coleoptera, Buprestidae)

BACKGROUND: Two jewel beetle species native to Europe, the cypress jewel beetle, Lamprodila (Palmar, Ovalisia) festiva L. (Buprestidae, Coleoptera), and the sinuate pear tree borer, Agrilus sinuatus Olivier (Buprestidae, Coleoptera), are key pests of ornamental thuja and junipers and of orchard and ornamental rosaceous trees, respectively. Although chemical control measures are available, due to the beetles’ small size, agility, and cryptic lifestyle at the larval stage, efficient tools for their detection and monitoring are missing. Consequently, by the time emerging jewel beetle adults are noticed, the trees are typically significantly damaged. METHODS: Thus, the aim of this study was to initiate the development of monitoring traps. Transparent, light green, and purple sticky sheets and multifunnel traps were compared in field experiments in Hungary. RESULTS: Light green and transparent sticky traps caught more L. festiva and A. sinuatus jewel beetles than non-sticky multifunnel traps, regardless of the larger size of the colored surface of the funnel traps. CONCLUSIONS: Although light green sticky sheets turned out to be optimal for both species, using transparent sheets can reduce catches of non-target insects. The key to the effectiveness of sticky traps, despite their reduced suitability for quantitative comparisons, may lie in the behavioral responses of the beetles to the optical features of the traps

Responses of Pseudovadonia livida adults to olfactory and visual cues

Pseudovadonia livida (F.) (Coleoptera Cerambycidae Lepturinae) is a widely distributed and common species across Europe. This study was undertaken to investigate some aspects of the sensory and behavioural ecology of P. livida adults in relation to flowering plants they visit. First, their electroantennogram (EAG) responses to 42 synthetic plant volatile compounds were recorded.The antennae gave the strongest EAG responses to methyl anthranilate, methyl salicylate and 2-phenylethyl alcohol. In a field trapping experiment, P. livida beetles preferred fluorescent yellow and yellow traps over white, blue and transparent traps. When we compared different chemical lures, loaded with EAG-active compounds and their blends, in fluorescent yellow traps, we found that the beetles responded stronger to the two-component blend of methyl anthranilate and 2-phenylethyl alcohol than to other lures tested. In a subsequent experiment testing different ratios of these two compounds, the highest number of P. livida adults was recorded in traps baited with a ratio of 1:1 (100 mg of each compound) of methyl anthranilate and 2-phenylethyl alcohol, followed by traps with the 10:1 ratio. Thus, 1:1 and 10:1 blends of methyl anthranilate and 2-phenylethyl alcohol in fluorescent yellow traps are suitable for detection and monitoring of P. livida

Responses of Pseudovadonia livida adults to olfactory and visual cues

Pseudovadonia livida (F.) (Coleoptera Cerambycidae Lepturinae) is a widely distributed and common species across Europe. This study was undertaken to investigate some aspects of the sensory and behavioural ecology of P. livida adults in relation to flowering plants they visit. First, their electroantennogram (EAG) responses to 42 synthetic plant volatile compounds were recorded.The antennae gave the strongest EAG responses to methyl anthranilate, methyl salicylate and 2-phenylethyl alcohol. In a field trapping experiment, P. livida beetles preferred fluorescent yellow and yellow traps over white, blue and transparent traps. When we compared different chemical lures, loaded with EAG-active compounds and their blends, in fluorescent yellow traps, we found that the beetles responded stronger to the two-component blend of methyl anthranilate and 2-phenylethyl alcohol than to other lures tested. In a subsequent experiment testing different ratios of these two compounds, the highest number of P. livida adults was recorded in traps baited with a ratio of 1:1 (100 mg of each compound) of methyl anthranilate and 2-phenylethyl alcohol, followed by traps with the 10:1 ratio. Thus, 1:1 and 10:1 blends of methyl anthranilate and 2-phenylethyl alcohol in fluorescent yellow traps are suitable for detection and monitoring of P. livida

Field Screening for Attractants of Scarab (Coleoptera: Scarabaeidae) Pests in Hungary

In field screening tests conducted on selected pest scarabaeids in Hungary, Epicometis (Tropinota) hirta (subfamily Cetoniinae) was attracted to traps baited with either cinnamyl alcohol or trans-anethol. In some tests attraction was also detected to phenethyl alcohol or cinnamyl acetate. In other tests, adults of Cetonia aurata aurata and Oxythyrea funesta (subfamily Cetoniinae) also were attracted to trans-anethol, while the ternary mixture of phenethyl propionate, eugenol and geraniol attracted Potosia cuprea (subfamily Cetoniinae). Some attraction of Valgus hemipterus (subfamily Valginae) to cinnamyl alcohol also was observed. All of the above species are pests of more or less economic importance in Hungary. The attractant chemicals discovered in the present study will form a starting point for the development of effective attractants for the respective pest scarab species

Diel rhythmicity of field responses to synthetic pheromonal or floral lures in the western corn rootworm Diabrotica v. virgifera

Western corn rootworm (WCR) ( Diabrotica v. virgifera Le Conte) (Coleoptera, Chrysomelidae) adults were attracted only during daytime hours and showed a bimodal diel activity pattern when responding to the synthetic floral bait in the field. On the other hand, to the synthetic pheromone bait, good responses were recorded apart from daytime hours also well into the night. The present results suggest that in WCR the pheromonal communication channel and the channel connected with feeding (= floral lure) are separated

Development of Trapping Tools for Detection and Monitoring of Diabrotica v. virgifera in Europe

Trap designs baited with the synthetic sex pheromone have been optimized for trapping of the western corn rootworm Diabrotica v. virgifera LeConte (Coleoptera: Chrysomelidae) (WCR), which has recently been introduced into Europe. The best trap design proved to be the sticky “cloak” trap (code name “PAL”), which catches only males, and is being used in many countries of Europe for detection and monitoring the spread of the new pest. Preliminarily the range of attraction (as defined by Wall and Perry, 1987) of the pheromone traps was estimated to be <10 m. The performance of yellow sticky plates (used by others for monitoring of the pest) was insignificant as compared to the activity of the pheromone baited traps, and yellow colour had no discernible effect on catches in pheromone traps. The known floral lure of WCR containing 4-methoxy-cinnamaldehyde and indole proved to be active also towards the population in Europe, attracting both females and males. Yellow colour slightly increased catches by the floral lure, hence a yellow sticky “cloak” trap has been developed (code name PALs). Pheromone baited PAL traps caught a total of about 4 times more beetles than the floral baited PALs, which latter however appeared to be preferentially active for females. When placed into the same trap, the pheromonal and floral lures did not interfere with each other's activity