The effect of sandy soil, bacterium dose and time on the efficacy of Pasteuria penetrans to control Meloidogyne incognita race 1 on coffee

Abstract

An obligate parasite bacterium of the root-knot nematode, Pasteuria penetrans strain P10, isolated from Meloidogyne incognita females on banana roots in Imperatriz Maranhão State, Brazil, was evaluated in glasshouse conditions, using two doses of a dry root bionematicide (10 7 endospores (5.0 g/seedling) and 10 6 endospores (0.5 g/seedling)) on seedlings of cv. Mundo Novo coffee. The soil in which coffee seedlings were raised was inoculated previously with these two doses of P. penetrans and after 2 months the plants were transferred to soils of different textures: clay-sandy soil (38% clay, 2% silt and 60% sand) and sandy soil (17% clay, 0% silt and 83% sand). When the coffee plants were 30 cm high, they were inoculated with 20 000 eggs/plant of M. incognita race 1. The coffee plants were examined 8, 16 and 24 months after nematode plant infestation. The effectiveness of the biological control was determined by the reduction of nematode reproduction factor, which ranged from 62 to 67% in clay-sandy soil and 80 to 85% in sandy soil. The mechanism of suppression caused by the bacterium was evaluated by the percentage of infected second-stage juveniles (J2), number of endospores attached/J2 and number of infected females. The high levels of suppression were related to time, increasing from 8 to 24 months, and to the percentage of sand in the soil.

Effect of Nutrition and Soil Function on Pathogens of Tropical Tree Crops

“…Stirling et al (1992) isolated fluorescent pseudomonads from avocado soils suppressive to P. cinnamomi (causing root rot) and demonstrated their in vitro antagonism to the pathogen. In vivo control of the root-knot nematode on coffee roots, Meloidogyne incognita, by the application of an obligate bacterial parasite of the nematode, a strain of Pasteuria penetrans, was demonstrated by Carneiro et al (2007). The colonisation of banana roots by the nematode Radopholus similis could be decreased by inoculation of the banana plants with a non-pathogenic isolate of F. oxysporum (Paparu et al, 2008).…”