BIOLOGICAL CONTROL OF PHYTOPHTHORA SPP. USING ENDOPHYTIC FUNGI ISOLATED FROM COCOA (Theobroma cacao L.) PODS AND LEAVES

Abstract

Cocoa (Theobroma cacao L.) is one of the several important agricultural commodities, which had over the years been adversely affected by black pod disease caused by Phytophthora spp. This study investigated the potentials in the use of endophytic fungi isolated from healthy cocoa pods and leaves as biocontrol agents against Phytophthora megakarya infections (black pod) in cocoa. Moderately aggressive strain of P. megakarya was isolated from symptomatic cocoa black pod and inoculated against endophytic fungi obtained from healthy cocoa pods and leaves. The endophytes were screened for their antagonistic effects against the Phytophthora sp. in vitro, using dual culture assay. Results from this study showed that two of the endophytic isolates: Trichoderma asperellum (83.92%), Trichoderma harzianum (75.35%) exhibited strong inhibitions against the Phytophthora isolate, indicating their potentials as biocontrol agents against the pathogen, while others: Fusarium solani (17.58%), F. oxysporium (17.55%), Colletotrichum gloesporidodes (17.90%), Curvularia lunata (14.70%) and Pythium ultimum (13.60%) gave weak inhibitions against Phytophthora megakarya in vitro. Findings from this study demonstrated that some endophytic fungi from cocoa pods and leaves could significantly reduce or slow down Phytophthora spp. infection rates on cocoa. Hence, the potentials inherent in the use of endophytic fungi as sustainable eco-friendly biocontrol strategy in the management of black pod disease of cocoa in Nigeria, is established.