Biocontrol of Fusarium wilt of cucumber with Trichoderma longibrachiatum NGJ167 (Rifai)

Abstract

Aim: This research investigated the use of Trichoderma longibrachiatum NGJ167 (Rifai) as a biocontrol agent of Fusarium wilt in cucumber varieties (Ashley and Marketmoor) both in the screenhouse and on the field. Study Design: The screenhouse experiment was laid down in a Completely Randomized Design (CRD) while Randomized complete block design (RCBD) was used for the field experiment. Place and Duration of Study: The study was conducted at the National Horticultural Research Institute, Ibadan between 2012 and 2013. Methodology: Soils were inoculated with mycelial plugs of T. longibrachiatum NGJ167 before planting while the control soil was mock-inoculated with agar plugs of Potato dextrose agar (PDA). Two weeks after planting, F. oxysporum was inoculated into the soils in the screenhouse while natural infection was allowed to occur on the field. The biocontrol abilities of T. longibrachiatum NGJ167 on F. oxysporum was observed on disease incidence and severity and the fruit yield. The presence of T. longibrachiatum NGJ167 genes was detected in the treated cucumber fruits to ensure consumers’ safety. Results: The control plants had higher incidence and severity of F. oxysporum than the T. longibrachiatum-treated plants. The T. longibrachiatum NGJ167-inoculated Marketmoor had higher fruit weight value of 200g in the screenhouse when compared with the control which had a fruit weight value of 133.33 g. On the field, T. longibrachiatum-treated Marketmoor produced the highest fruit weight of 220 g while the control had a mean weight of 120.6 g. Results also revealed that T. longibrachiatum DNAs were absent in the inoculated cucumber fruits. Conclusion: The use of T. longibrachiatum NGJ167 as a biocontrol agent indicates its potentials in improving plant health in agriculture. The absence of T. longibrachiatum NGJ167 in the treated cucumber indicated that the consumption of such fruits will have no adverse effect on consumers’ health.