CONICET | Buscador de Institutos y Recursos Humanos

Several species of grasshoppers are attracted to vegetable oils. These oils have kairomonal properties due primarily to the presence of linolenic and linoleic fatty acids. The current study aimed to determine whether the odours of canola, flax and olive oils are attractive to Dichroplus vittigerum and if they induce preference and feeding. For this purpose, we conducted wind tunnel bioassays, to determine if oil odours induced attraction. We also conducted preference tests comparing feeding by D. vittigerum of leaves of xx taraxacum, treated with the oils versus control leaves. We also determined whether treatment with the oils induced feeding of a substrate which is not a natural food resource, filter paper. In wind tunnel bioassays, all the oils induced attraction, similar to that of taraxacum leaves. Phagostimulation results showed that among the oils tested, flax oil was the only one that acted as phagostimulant, as treated filter papers we consumed by D. vittigerum. However, in preference bioassays, grasshoppers did not exhibit a preference for leaves that were treated with xx microliters of any of the oils. Although grasshoppers fed on filter paper treated with flax oil and were attracted to the odour in wind tunnel bioassays, treatment of taraxacum leaves with the oils did not increase feeding on them. We hypothesize that taraxacum leaves are inherently attractive and treatment with oils did not affect feeding on them. . Our results provide a starting point for the development of toxic baits that can be used to attract and control these harmful insects, presenting flax oil as a potential bait for this species since its odour was both attractive and led to increased feeding or phagostimulation. Future studies should test the effect of the oils on other plant species or at varying doses, under field conditions.

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