Status and non-chemical management of ginger rhizome diseases in Himachal Pradesh

Ginger (Zingiber officinale Rosc.) is one of the important spice crops of Himachal Pradesh. The crop is grown in districts of Sirmaur, Solan, Shimla, Bilaspur and Mandi where it is affected every year to a larger extent by Pythium and Fusarium rhizome diseases. The intensity of rhizome diseases further aggravates with the involvement of congenial weather and occurrence of root knot and lesion nematodes in soil. These rhizome diseases are both rhizome seed and soil borne. Pythium incidence during the last few years was found more than Fusarium among ginger rhizome diseases in all the districts. Among the nematodes, Meloidogyne population was found more than the Pratylenchus. The present study also included the variability among the isolates of Pythium collected from different areas of the state. Hot water treatment of ginger rhizomes at 45°C for 30 minutes excluded the rhizome borne inoculum through eradication. Antagonistic activity of two fungi and two bacteria was studied. All the potent microorganisms significantly inhibited the test pathogens in vitro. However, maximum inhibition of Pythium was recorded by Trichoderma harzianum followed by T. hamatum and G3PGPR while G4PGPR gave maximum inhibition of Fusarium followed by T. harzianum. Phosphate solubilizing activity was shown more by T. harzianum followed by T. hamatum and G4PGPR while maximum siderophore activity was shown by G3PGPR followed by G4PGPR. The total microbial population in rhizosphere soil was also influenced by cabbage biofumigation followed by mustard and PGPR consortia. Among the microbial population in rhizosphere soil, fungi and bacteria dominated when evaluated for the management of ginger rhizome diseases.