Effects of associations of cabbage with Mentha arvensis L. and Lippia alba (Mill.) N. E. Brown on insect pests of Crucifera at an experimental station

Abstract

Headed cabbage (Brassica oleracea L.) is a leafy vegetable facing enormous damage by insect pests. To deal with these insects, chemical control remains the main method used with its harmful consequences on the environment and human health. The objective of this study is to evaluate the effects of intercropping head cabbage with field mint (Mentha arvensis L.) and white verbena (Lippia alba (Mill.) N. E. Brown) on the main insect pests and cabbage yield. So, a trial was carried out at the Agronomic Experimentation Station of the University of Lomé using a device in complete randomized random blocks with 3 repetitions. Each block comprised seven elementary plots: (control (T0); cabbage plants surrounded by mint plants (Me); cabbage plants surrounded by white verbena plants (Ve); cabbage plant inserted in white verbena (Vi); cabbage plant interspersed among mint plants (Mi); cabbage plants interspersed with white verbena and mint plants (ViMi); cabbage plants surrounded by mint plants and white verbena (VeMe)). The insect pests identified were: Plutella xylostella L., Spodoptera littoralis Boisd., Chrysodeixis acuta Walker, Hellula undalis Fabricius, Alpenus maculosa Stoll., and Lipaphis erysimi Kalt. The crop associations presented low numbers of insect pests, and higher yields (1.38 to 2.31 t/ha) compared to the control (0.00 t/ha). The results of this study could inform an integrated program set up to fight insect pests of cabbage.