Aphid Behavior on Amaranthus hybridusL. (Amaranthaceae) Associated with Ocimumspp. (Lamiaceae) as Repellent Plants

Various plant species contain biocidal and/or semiochemical components. These can be used for managing insect pests, in order to reduce the use of synthetic pesticides and to improve the quality of vegetable crops. This study was conducted to assess the effect of repellent plantsOcimum gratissimumL. andOcimum basilicumL. on aphidsAphis craccivoraKoch,Aphis fabaeScopoli andMyzus persicaeSulzer when they are associated withAmaranthus hybridusL. plants. The results have shown that in the two approaches tested-Ocimumsp. plants surrounded byA. hybridusplants and the dual-choice test-the number of aphids on theA. hybridusplant associated with eitherO. gratissimumorO. basilicumwas significantly less significant compared to theA. hybridusalone. This first study on the association betweenA. hybridusandOcimumspp. shows that theOcimumspecies might be used as an alternative method for controlling aphids in order to avoid the use of synthetic pesticides onAmaranthus. The ability ofOcimumspp. to repel pests can make it an important companion plant for farmers, because those plants can not only be used to control pests, but they can also be harvested, providing a direct economic return.