Abundance of natural enemies and aphids in okra crops (Abelmoschus esculentus - Malvaceae) diversified with Tithonia rotundifolia (Asteraceae)

Abstract

Aphids are one of the main problems in okra culture. However, in Brazil, family farmers do not have sustainable alternatives for its control. This pest has numerous natural enemies, and diversified crops are indicated to attract and conserve these control agents. Thus, our research aimed to evaluate the abundance of natural enemies and the presence of Aphis gossypii in okra using Tithonia rotundifolia (Asteraceae) as a companion plant. The work was carried out in an area of 200 m2, with three treatments (okra located at one, three and six meters from the companion plant) and two repetitions. Six samplings of aphids and natural enemies were carried out from December 2017 to March 2018. The natural enemies captured in the okra + T. rotundifolia system belong to 34 families, and the predators of the families Coccinellidae, Formicidae, Eutichuridae, Araneidae and Oxyopidae are the most frequent. Among the Coccinellidae, the species Scymnus loewii Mulsant & Easter was considered dominant, frequent and constant at the okra crop at three distances, being the only aphidophagous ladybug on the companion plant. The ant Solenopsis invicta Buren was dominant and frequent (62.55 %) in the okra crop. The cited spiders were frequent in both plants. Crop diversification with T. rotundifolia contributed to the reduction in A. gossypii in okra located one meter from the companion plant, mainly at 110 DAP. The benefits did not extend to okra grown at three and six meters from the companion plant. We evaluated the possible interactions and causes of population fluctuation of natural enemies and of the studied pest.