Abstract:
The inhibitory activity of selected invasive alien species leaf extracts against tomato
bacterial wilt was studied in vitro and greenhouse. In vitro inhibitory activity was
undertaken in a disc diffusion sensitivity test. Furthermore, aqueous extracts of
Eichhorina crassipes, Mimosa diplotricha and Lantana camara and methanolic
extract of Prosopis juliflora which showed better inhibitory effect in vitro were
evaluated against R. solanacearum in greenhouse on tomato. The plant extracts were
applied and evaluated at three different times of application (at the time of inoculation; two days before pathogen inoculation; and two days after pathogen inoculation).
The result showed that most of the treatment combinations significantly reduce disease incidence and area under disease progress curve and increase biomass of tomato
plants, but the effectiveness of tested plant species depends on the type of plant
species and application time. The application of plant extracts at the time of pathogen inoculation resulted in highest reduction of disease development on tomato
plants. Aqueous extract of E. crassipes was found to be the most effective plant
extract in disease suppression and increase above-ground biomass compared to
inoculated control. The study revealed that the tested plant species have a potential
of inhibiting the development of bacterial wilt on tomato.
