Influence of Some Cultural Practices on the Incidence and Severity of Leaf Spot Disease of <i>Telfairia occidentalis</i> in Dschang

Abstract

Fungi diseases are major diseases of Telfairia occidentalis (fluted pumpkin) in the major growing areas of the crop in Cameroon. This study was conducted between March and June in the cropping seasons of 2019 and 2020 to determine the effect of some cultural strategies viz. : tillage and no till, variation of sowing date and removal of diseased leaves on the incidence and severity of leaf spot disease caused by Phoma sorghina . There were four sowing dates, and two tillage systems with no variation in planting distance in the two cropping seasons. The design used was Randomized Complete Block Design (RCBD) with three replications. There were three plots for each sowing date within each replication. Seeds were sown at the rate of 1 m × 1 m, with four seeds per experimental unit. Data for disease incidence and severity was recorded every fortnight, commencing three weeks after emergence (WAE) and for a period of eight weeks for each sowing date. Disease incidence and severity was determined using Microsoft Excel 2010 and the data was subjected to statistical analysis and the means separated by Duncan Multiple Range Test (DMRT) at 95% confidence interval. In addition, the relationship between disease incidence and disease severity was also determined using Pearson correlation. Analysis of variance showed that there was no significant difference in leaf spot disease incidence at till and no-till units within this study period irrespective of sowing date. However, significant differences in leaf spot disease incidence and severity was recorded between the two cropping seasons. Sowing date four recorded the highest disease severity (1.611 ± 0.73) compared to sowing date two and three which was significant but comparable to sowing date one. The lowest disease severity (1.257 ± 0.697) was documented at sowing date two compared to sowing date one and four but comparable to sowing date three. Pearson correlation analysis revealed that there was a significant positive correlation (+0.560) between leaf spot disease incidence and severity which was statistically significant at α = 0.01 (p < 0.01). In order to enhance production of Telfairia occidentalis leaves with reduced disease incidence and severity, sowing dates two and three (first and second weeks of April respectively) coupled with removal of disease leaves every fortnight could regardless of tillage systems well manage leaf spot disease compared to sowing dates one and four.