Abstract:
Potato wilt caused by Ralstonia solanacearum causes great potato yield
reduction all over the world. Currently, there are no reliable chemicals for the
control of the disease. This study aimed at testing the sensitivity of R.
solanacearum isolates to crude extracts from Punica granatum. Symptomatic
Irish potato plants samples were collected from the field and R. solanacearum
isolated using Kelman’s TZC. P. granatum samples were purchased from
Njokerio market and crude extracts obtained. The chemical constituents of the
crude extracts were established using GC-MS. Sensitivity test of R.
solanacearum was carried out using Kirby Bauer disk diffusion technique and
MICs and MBCs values determined. There was a significant difference in the
weights of crude extracts obtained from the seeds of P. granatum using hexane,
ethyl acetate and methanol (F=140.7 P=0.00468). The diameter of the zones of
inhibition presented by the extracts from the fruit peels extracted using hexane,
ethyl acetate and methanol varied significantly (F= 85.58 P=0.007). Similarly,
there was a significant difference in the diameter of zones of inhibition from
hexane, ethyl acetate and methanol crude extracts from the seeds (F=85.14
P=0.008). The MICs of extracts from the fruit peels, seed extracts and the
tetracycline control varied significantly (F= 1484.53 P=0.00043). In addition,
there was a significant difference in MBCs presented by the peel extracts, seed
extracts and the tetracycline control (F=17934.03 P=0.00014). There is need for
mass production of extracts from P. granatum.
