Efficacy of selected bio-control agents on Meloidogyne incognita on eggplant

Abstract

The biocontrol effects of Serratia marcescens (1 × 109 bacterium cells/ml water), ground ascaris (Ascaris lumbricoides) cuticle (10 g/pot), two entomopathogenic nematode species (Heterorhabditis bacteriophora strain EGG and Steinernema carpocapsae strain All, each at 125 infective juveniles/cm2), and garlic extract (600 g ground garlic cloves/l water), used as soil treatments, were assessed on Meloidogyne incognita attacking eggplant (cv. Roomi Balady) in the glass-house. These treatments were compared with spray application of the nematicide oxamyl (15 ml solution/pot from a stock of 3 litres of 24% liquid oxamyl + 600 litres water). Fifty-three days after M. incognita inoculation, all of the bio-control agents increased various measures of plant growth. The root weights of plants treated with ascaris cuticle were almost doubled, but shoot weights were greatest in plants treated with oxamyl, followed by those of plants that received S. marcescens, S. carpocapsae and ascaris cuticle. Since much Bacillus subtilis was found in ascaris cuticle-treated pots (138 bacterial cells/g of treated soil) with respect to the control (28 bacterial cells/g), it is likely that ascaris cuticle could be used for culturing this bacterium, which apparently controlled M. incognita. The treatments delayed the development of M. incognita and second stage juveniles occurred only in control pots. Numbers of third and fourth stage juveniles, females and egg masses of the nematode, root galls and gall index were reduced by all treatments, with the greatest reduction (95-98%) given by ascaris cuticle.