Evaluation of the Maize - False basil Cultural Association in the Fight against the Fall Armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae)

In Ivory Coast, maize (Zea mays L.) is the second most cultivated cereal after rice. Despite this, maize cultivation is limited by pest pressures. Apart from the usual pests, a new enemy has arrived on the continent, the fall armyworm, Spodoptera frugiperda. To control this pest, farmers use pesticides, which are not only expensive, but also pose risks to human health and the environment. The objective of this study is to find an alternative solution to chemical control through the cultivation of maize-Ocimum gratissimum (False basil) in two ways. The first consisted in planting False basil around the maize plot as a barrier plant (P1). The second consisted of alternating maize plants with False basil plants (P2). The experimental design used was a one-factor randomized FISHER block with three treatments. The efficacy of the two association modalities was compared to that of control which was maize crop only. The results showed better control of fall armyworm in the combination than control. Of the two combination treatments, it was the P1 treatment that was effective against S. frugiperda compared to the P2 treatment and the control. Thus the infestation rate of treatment P1 (33 %) was lower than that of treatment P2 (50 %) followed by the control (70 %). In addition, it was the P1 treatment that harbored fewer armyworms (8 larvae) compared to the P2 treatment (22 larvae) and the control (35 larvae). The maize-False basil crop combination therefore appears to be beneficial than pure crops as it significantly reduces the infestation rate, damage level and harbors less fall armyworm population.