On-Farm Evaluation of Deleafing Frequency on the Severity of Black Sigatoka Disease (Mycosphaerella fijiensis Morelet) and Yield of Banana (Musa spp)

Bananas are susceptible to the highly damaging black Sigatoka disease (BSD) caused by the fungus (Mycosphaerella fijiensis). The objective of this study was to evaluate the effect of leaf pruning frequency on the control of the BSD and the yield of banana. The study was carried out at Njombe (Lat 4º 36’ N, Long 9º 40’ E, 170 m above sea level) in a randomized complete block design with four treatments (3-day, 6-day, 9-day and 12-day pruning frequencies) and three replications. Data were collected on the different stages of evolution of the disease, percentage infection rate, weekly rate of leaf loss, number of leaves at harvest, yields (bunch weight and mid finger circumference and the monetary value of the yields. The results show that the highest maximum percentage rate of infestation of the disease (54.00 % and 50.53 %) was recorded in the 12-day and 9-day frequencies respectively. The lowest weekly rate of leaf loss (0.82 and 0.85 leaves/week) was recorded in the 6-day and 3-day frequencies which differ significantly from 1.90 and 1.38 leaves/week in the 12-day and 9-day frequencies. A statistically significant difference was recorded in the number of leaves at harvest with the highest of 4.20 leaves recorded in the 6-day frequencies. The highest average bunch weight of 32 kg (26.10 %) estimated at 57.36 t/ha was recorded in the 6 day frequency, while 36.8 cm average mid finger circumference was recorded in the 3-day frequency. The 6-day frequency registered the highest monetary value of USD 52,184 /ha, which does not differ significantly from that of the 3-day frequency of USD 52, 021 /ha. The lowest monetary value was recorded in the 12-day frequency of USD 45, 878. From the results of the study, the 6-day pruning frequency could be recommended for practice to accompany the chemical control