PGPR and entomopathogenic fungus bioformulation for the synchronous management of leaffolder pest and sheath blight disease of rice.
BACKGROUND
The biological control of plant pests and diseases using a single organism has been reported to give inconsistent and poor performance. To improve the efficacy, bioformulations were developed possessing mixtures of bioagents.


RESULTS
Bioformulations combining Pseudomonas fluorescens Migula strains Pf1 and AH1 and Beauveria bassiana (Balsamo) Vuill. isolate B2 were developed and tested for their efficacy against leaffolder pest and sheath blight disease on rice under glasshouse and field conditions. The combination of Pf1, AH1 and B2 effectively reduced the incidence of leaffolder insect and sheath blight disease on rice compared with other treatments. An in vitro assay of leaffolder preference to rice leaf tissues treated with Pf1 + AH1 + B2 biformulation showed variation from normal growth and development of leaffolder larvae. Plants treated with the Pf1 + AH1 + B2 combination showed a greater accumulation of enzymes, lipoxygenase and chitinase activity against leaffolder insect compared with other treatments. Similarly, the plants showed a higher accumulation of defence enzymes, peroxidase and polyphenol oxidase activity against sheath blight pathogen in Pf1 + AH1 + B2 treatment compared with the untreated control. The bioformulation mixture attracted the natural enemy population of leaffolder under field conditions. In addition, a significant increase in rice grain yield was observed in Pf1 + AH1 + B2 treatment compared with the untreated control.


CONCLUSIONS
The combination of P. fluorescens strains and B. bassiana isolate effectively reduced the incidence of leaffolder insect and sheath blight disease on rice plants and showed the possibility of controlling both pest and disease using a single bioformulation.
Karthiba
Loganathan
L
Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore 641 003, India.
Saveetha
Kandasamy
K
Suresh
Seetharaman
S
Raguchander
Thiruvengadam
T
Saravanakumar
Duraisamy
D
Samiyappan
Ramasamy
R
D000818:Animals; D052982:Beauveria / Q000502:physiology*; D004156:Catechol Oxidase / Q000378:metabolism; D007814:Larva / Q000382:microbiology; D012275:Oryza / Q000201:enzymology / Q000254:growth & development* / Q000382:microbiology* / Q000502:physiology; D009195:Peroxidase / Q000378:metabolism; D010572:Pest Control, Biological / Q000379:methods*; D010935:Plant Diseases; D011551:Pseudomonas fluorescens / Q000502:physiology*; D011679:Pupa / Q000382:microbiology
D004156:Catechol Oxidase; D009195:Peroxidase