Studies on root-knot, root-rot pea mosaic virus complex of Pisum sativum

Abstract

Pea mosaic virus caused more damage to Pisum sativum cv. Sutton Phenomenon than either Meloidogyne incognita or Rhizoctonia solani. All three pathogens individually suppressed nodulation but R. solani had the greatest effect. Greatest plant growth reduction but least nematode mutiplication, root-knot development and nodulation were caused by simultaneous inoculations with all three pathogens. Nematode-virus combinations were more damaging than nematode-fungus combinations. Simultaneous inoculation with either nematode-virus or nematode-fungus and nematode inoculation preceding either virus or fungus caused more damage than prior inoculations either with fungus or virus followed by nematodes 10 days later. M. incognita and R. solani, together, acted synergistically to reduce plant growth. R. solani, singly or in different combinations with nematodes, and prior virus inoculation followed by nematodes 10 days later, produced an inhibitory effect on nematode mutiplication, root-knot development and nodulation while simultaneous nematode-virus inoculation or nematode inoculation followed by virus 10 days later significantly increased nematode multiplication and root galling. Virus-fungus combinations caused greater damage when fungus inoculation preceded virus but was reversed when virus preceded fungus inoculation. Virus-fungus combinations showed a slight additive effect on plant growth reduction but the virus inhibited fungus development and thus its pathogenic effect.