Assessment of Bacterial Biocontrol agents Formulations against Anthracnose of Cashew (Anacardium occidentale L.) in Côte d’Ivoire

Abstract

The cashew tree (Anacardium occidentale L.) is of vital importance to the Ivorian economy. Côte d’Ivoire is first world producer. However, its cultivation faces several constraints linked to anthracnose. The aim of this study was to assess the efficacy of two formulated bacterial biocontrol agents against anthracnose of cashew. To this end, in vitro confrontation tests were carried out against Colletotrichum gloeosporioides with two previously formulated bacterial biopesticides. Biocontrol tests were then carried out against anthracnose in greenhouses and cashew plantations. The results showed that the two bacterial biocontrol agents tested controlled in vitro the proliferation of Colletotrichum gloeosporioides responsible for anthracnose and significantly reduced the disease severity index on cashew seedlings in the greenhouse. In vitro, inhibition rates ranging from 70.16±6.9 to 72.65±6.5% were observed on the mycelial growth of Colletotrichum gloeosporioides. In the greenhouse and in cashew plantations, a sharp reduction in the anthracnose severity index was observed. In the greenhouse, anthracnose reduction rates by the two bacterial biocontrol agents ranged from 62.80 ± 5.2% to 85.95 ± 2.8%. In cashew plantations, the reduction rates varied from 42.24 to 41.05%. In view of the above, these two bacterial biocontrol agents could be used for biological control of cashew anthracnose in Côte d'Ivoire.