©2020 Scienceweb Publishing Evaluation of heat treatment and bio-priming of cowpea seeds for the management of fusarium wilt disease in the screen house Ayodele M. Ajayi * • Bosede J. Evbenata Department of Crop, Soil and Pest Management. Federal University of Technology, Akure, P. M. B, 704, Akure, Ondo State, Nigeria. *Corresponding author. Email: ajayimy25@yahoo.com; Tel: 08132158030 Accepted 29 th January, 2020. Abstract. Fusarium wilt is one of the most devastating diseases of cowpea. The pathogen, Fusarium oxysporum f.sp. tracheiphilum is soil and seed-borne. A non-chemical approach was designed for the management of the disease in the present study. Hot water (physical) at three temperatures, 40 50 and 60°C, and Trichoderma viride (biological) at 10 6 spores/ml were evaluated singly and synergistically in the laboratory. The duration of exposure to hot water was 5 min, after which seeds were allowed to cool followed by priming in sterile water (sole hot water treatment) or T. viride (synergistic physical and bio-control) medium in Petri-dishes for 72 h. The control consisted of seed treated with water at ambient temperature, while the standard check was seeds dressed with Mancozeb fungicide. Both were primed in a sterile water medium. Nine treatments were evaluated in all. Germinated seeds were transplanted into plastic pots containing soil infested with F. oxysporum at 10 6 spores/ml in the screen house. The experimental layout was completely randomized design and data collected were subjected to statistical analysis and mean separation. Results showed that seeds treated with 50°C hot water only had the highest germination percentage, 96.66%, and seedling vigour, 460.98. Disease incidence and severity values were least in seeds treated with synergistic hot water at 50°C and priming in T. viride medium. The highest number (77.33) and weight (13.41 g) of seeds were also recorded for the same treatment, while the least, 18 and 3.60 g were obtained from control. Integrated use of hot water (50°C) and bio-priming in T. viride medium can be recommended for use in the management of fusarium wilt disease of cowpea. Keywords: Fusarium wilt, cowpea, hot water, Trichoderma viride, germination, vigour, yield. INTRODUCTION Cowpea [Vigna unguiculate (L.) Walp], is believed to have originated from Africa (Baudoin and Marchal, 1985; Pasquet, 2000; FAO, 2004). It is a member of the Fabaceae family and is cultivated mostly in the arid, semi-arid tropic and sub-tropical countries. This is due to its hardiness and tolerance to drought stress (Muoneke et al., 2012; Ajayi et al., 2018). The crop is important for its numerous agricultural, nutritional and health benefits (Owolade et al., 2006; Singh et al., 2006; Tariku, 2008). It is an important source of cheap protein for millions of poor Africans who cannot afford other sources like meat and egg that are considered to be more expensive. Nigeria is a leading producer of cowpea in the world (FAO, 2014) but pests and diseases have remained a serious challenge threatening production, especially in the humid rain forest zone (Singh et al., 1990; Adegbite and Amusa, 2008). Significant annual yield losses have been reported (Muhammed and Sajo, 2018, Kusi et al., 2019). One of the most devastating diseases of cowpea in Nigeria is Fusarium wilt. A strain of the causative organism was identified as F. oxysporum f.sp. tracheiphilum Race 1 in 1980 (Armstrong and Armstrong, 1980). F. oxysporum is Journal of Agricultural and Crop Research Vol. 8(2), pp. 20-32, February 2020 doi: 10.33495/jacr_v8i2.19.169 ISSN: 2384-731X Research Paper