Influence of Sowing Date and Removal of Disease Leaves on the Incidence and Severity of lLeaf Spot Disease in Telfairia occidentalis

Abstract

Diseases of fungi origin are important diseases of Telfairia occidentalis (fluted pumpkin) in the main growing areas of the leafy vegetable in Cameroon. A study was conducted between March and June in the cropping seasons of 2019 and 2020 in Dschang to determine the influence 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, with no variation in planting distance in the two cropping seasons. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. Each replication had three experimental units with similar sowing dates. 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 and the data was subjected to statistical analysis and the means separated by Duncan Multiple Range Test (DMRT) at 95% confidence interval. Analysis of variance revealed that there was a significant difference (p ≤ 0.05) in leaf spot disease incidence between sowing date two and sowing dates one, three and four. Sowing date four recorded a very high leaf spot disease incidence (22.464 ± 16.718) and severity (1.625 ± 0.836). The first cropping season registered a higher and significant (p ≤ 0.05) leaf spot disease incidence and severity compared to the second cropping season. In order to enhance production of leaves, and reduced disease incidence and severity of Telfairia occidentalis, sowing date two (corresponding to the first week of April) besides removal of diseased leaves every fortnight could well manage leaf spot disease compared to sowing dates one three and four.