Screening Of Floral Attractants For Trapping Scarab Beetles Using Uniform Design Of Mixture

In order to clarify the interations among the floral volatiles, to explorean appropriate floral attractant screening method, and to provide products andtechnical support for the chafers’ green prevention and control, the author studied theattractiveness of14common floral volatiles to scarab beetles in the field byintroducing uniform design of mixture and agaropectin inclusion technology, thereagents included methyl salicylate, methyl benzoate, ethyl benzoate, benzyl acetate,salicylaldehyde, benzaldehyde, phenylacetaldehyde, cinnamaldehyde, benzyl alcohol,β-phenethyl alcohol, geraniol, linalool, eugenol, and acetophenone. The main resultswere reported as follows:(1) When the floral volatiles were tested alone, only phenylacetaldehyde andgeraniol had obvious attractiveness in the field trapping, and phenylacetaldehydecaught more remarkable number of scarab beetles than geraniol did, while the rest ofthe floral volatiles had no attractiveness, which suggested that multiple floral volatilesmust be involved in the flower visiting behavior of scarab beetles and actedsynergistically.(2) We introduced UM design into the mix of the blends in the field trapping.From the results, we found that there were some significances in many two-wayinteractions among these floral volatiles by stepwise regressing. The interactionregression coefficient of the binary phenylacetaldehyde and benzyl acetate reached anextreme significant level (t=10.38， P <0.0001), which indicated that the baniryplayed a key role in the floral volatile lure, the interaction regression coefficient ofbinary geraniol and phenylacetaldehyde reached a significant level (t=10.69， P <0.0001). However, the results also revealed that the binary benzyl acetate andeugenol had a synergitic effect on Holotrichia oblita (t=4.40，P <0.0001) trapping,while benzyl acetate and cinnamaldehyde had a synergitic effect on Anomalacorpulenta catch.(3) I studied the effects of different ratios and dosages of phenylacetaldehyde andbenzyl acetate in the field catch. The results of the ratios experiment showed that anextreme significant difference was revealed in the amount of the catch with differentratios (F=5.07， F0.01=4.46), the binary blend of600μL phenylacetaldehyde:400μL benzyl acetate was the optimal candidate lure, in which phenylacetaldehyde played amore important role in the binary. Moreover, the result indicated thatphenylacetaldehyde and benzyl acetate with the ratio fixed at3:2had an decisiveinfluence on the trap catch, while different dosages caught about equivalent numbersof scarab beetles. So we recommended the blend of120μL phenylacetaldehyde plus80μL benzyl acetate to use in practice to reduce the controlling cost.(4) The auther tested some other floral lure what added some other floralvolatiles in the phenylacetaldehyde and benzyl acetate baniry outside. Analysis of thethe results demonstrated ethanol had an influence on the trap of Holotrichiaoblita,whose regression coefficient of dose values reached a significant level (t=3.80, P<0.0001), while β-phenethylalcohol could attract a large number of Anomalacorpulenta,whose regression coefficient of dose values reached a significantlevel (t=7.53，P <0.0001) as well. What’s more, the result revealed methyl benzoateand ethyl benzoate whose chemical structure were similar to benzyl acetate didn’twork in the scarab beetles trapping.