Biocontrol of Potato Brown Rot and Root-Knot Diseases in Egypt

Potatoes are Egypt's largest horticultural export crop. Current quarantine restrictions on the potato brown rot disease impose serious limitations to such exportation, especially to the European Union countries. Also, all potato cultivars are susceptible to root-knot nematodes (Meloidogyne spp.) which degrade potato yield in size and quality. In this study, in vitro production of biocine from the bacterium Pantoea agglomerance was used against Ralstonia solanacearum as a causal agent of brown rot in naturally infected soil at Apis and Desouk districts, Egypt. The potato tubers were soaked in the biocine solutions or powdered by talk powder (3g/ plant) containing the biocine agent for 30 min prior to cultivation. Plants of both treatments were then powdered near the stem base every 10 days for 8 times. Average disease incidence was 26 and 11% in untreated and treated plants, respectively, with insignificant difference between soaking and powdering treatments. Morphological and biochemical traits of the bacterial isolates identified them as R. solanacearum race3 biovar 2. The highest potato yield and inhibition of the rot disease were shown by Morenka variety treated with Biocine agent In another test, the doses of furfural, biocine and biocontrol agents significantly (at P <= 0.05) reduced population density of the root-knot nematode, Meloidogyne arenaria, infecting potato cv. Diamont. The treatments differently reduced numbers of M. arenaria juveniles in soil, egg-masses and galls on roots. Increase in potato yield/plant and protein content in roots were not consistent with the reduction in these M. arenaria population parameters.