IN VITRO ACTIVITY OF TRICHODERMA SPECIES ON FUNGI CAUSING POST HARVEST DECAY OF PAWPAW (CARICA PAPAYA I) FRUITS IN MAKURDI
Abstract
A study was carried out to investigate in vitro activity of Trichoderma species on fungi causing postharvest decay of Pawpaw (Carica papaya) fruits in Makurdi. Samples of pawpaw fruits showing signs of decay were obtained from four markets in Makurdi namely; Wurukum, Wadata, High Level and Railway. The decaying pawpaw fruits were taken to the Botany Laboratory of the Benue State University for isolation of fungi. Small sections were cut from decaying fruits and surface sterilized in 5% sodium hypochlorite (NaOCI) solution for 1 minute and rinsed in several changes of sterile distilled water. Soil samples from farmlands within the premises of Benue State University, Makurdi were collected in polythene bags and taken to Botany Laboratory of the Benue State University for isolation of Trichoderma species. The Potato Dextrose Agar (PDA) was prepared according to the manufacturer’s instruction and used for fungi isolation. The serial dilution technique was used in isolation of Trichoderma from soil samples. The effect of Trichoderma species on the radial growth of the isolated fungi was carried out using the dual culture technique. Data were analysed using Analysis of Variance and means were separated using Fisher’s Least Significant Difference at 5% level of significance. The fungi isolated from decaying pawpaw fruits were; Aspergillus flavus, Aspergillus nigra and Bipolaris sp while Trichoderma koningii and Trichoderma viride were isolated from the soil samples. The results from the study revealed that there was no significant relationship in fungal occurrence based on locations (χ2 = 5.660; df = 2; P = 0.06). Bipolaris sp had the highest occurrence of 16(44.44%), followed by Aspergillus niger 11 (30.56%) and Aspergillus flavus with 9 (25.00%) respectively. Pawpaw fruits collected from Railway had the highest fungal occurrence 16 (44.44%) followed by Wurukum 9 (25.00%), high Level 8 (22.22%) and the least was observed in Wadata 3 (8.33%). The in vitro activity of Trichoderma koningii on radial growth of Bipolaris sp showed significantly higher radial growth in the control from 48 hours-120 hours (0.73±0.06, 1.10±0.10, 1.73±0.12, 3.00±0.10) compared with Bipolaris sp paired with Trichoderma koningii (0.44±0.06, 0.83±0.06, 1.23±0.12, 1.60±0.15)cm respectively. The in vitro activity of Trichoderma viride on radial growth of Bipolaris sp showed significantly higher radial growth in the control from 48 hours-120 hours (0.73 ± 0.06, 1.23±0.06, 2.00 ± 0.10, 3.17±0.53)cm compared with the Bipolaris sp paired with Trichoderma viride (0.43±0.12, 0.67±0.15, 1.03±0.12, 1.40±0.10)cm respectively. Similar trend was observed in radial growth of A. flavus and A. niger paired with T. koningii and T. viride compared with the control. The comparative in vitro activity of T. koningii and T. viride on Aspergillus niger, Aspergillus flavus and Bipolaris sp revealed there was no significant different in radial growth of Aspergillus niger, Aspergillus flavus and Bipolaris sp paired with T. koningii and T. viride (P>0.05) respectively. The pathogenicity revealed that area of rot (cm2) induced by A. niger (23.10 ± 7.50cm2) was significantly higher (P
Full-Text Access Notice
In accordance with the NERD Policy on promoting peer-reviewed publication, public access to the full text of a project, thesis or dissertation is restricted for three years, allowing the author and supervisors sufficient time to pursue peer-reviewed publication.
During this period, researchers with legitimate academic or research purposes may request authorisation directly from the author to enable NERD to release the indexed full texts of the work using the form below.