Allelopathic potential of eucalyptus (Eucalyptus globulus Labill.) leaf extracts on Physalis alkekengi L. germination and seedling growth

Worldwide, large amounts of herbicides are used for weed control. Problems due to the use of these herbicides have forced researchers to find more suitable methods for management of weeds. Some plants including Eucalyptus species have allelopathic properties that could be used in production of natural herbicides for weeds management. This investigation was performed in order to use Eucalyptus globulus Labill. leaf extracts to control Physalis alkekengi L. weed. The experiment included five types of solvent extracts consisting of aqueous, methanolic, ethyl acetate, acetonic and benzene and different concentrations of extracts at five levels (0, 1.25, 2.5, 5 and 10 gram per liter). Results showed that, in all solvent extracts, the inhibition level on germination and seedling growth increased by increasing the concentration of the extract. Among the extracts, methanolic and benzene extracts showed the highest allopathic effects, while aqueous and acetonic extracts showed the lowest one. According to the results, methanolic extract showed strong inhibitory effects on germination and seedling growth of P. alkekengi L. Therefore, it is possible to use methanolic extract at concentrations of 5 and 10 g/lit for controlling P. alkekengi L. Although benzene extract at high concentrations showed no strong inhibitory effect on germination, it was extremely effective in reduction of seedling growth that could be considered in management program of P. alkekengi L. control.