1.

Project Code

:

-

2.

Title

:

Control of mulberry diseases through botanicals and biocontrol agents.

3.

Investigators

:

Maji MD, Pratheesh Kumar PM, Chattopadhyay S, Gangwar SK.

4.

Project period

:

1998-2003

5.

Institute/ University

:

CSR&TI, Barhampore

6.

Project cost

:

-

7.

Objectives

• To identify botanicals for control of major foliar diseases of mulberry
• Isolation and identification of biocontrol agents for control of mulberry diseases.

8.

Important findings

Germination of conidia of Phyllactinia corylea was completely inhibited by leaf extract of Cassia sp. Germination of conidia of Pseudocercospora mori and Peridiopsora mori were completely inhibited by 5% bulb extract of Allium sp. And leaf extract of Detura sp. Maximum inhibition of colony growth of Myrothecium roridum observed with 5% solvent extract of Datura sp. Followed by Allium sp. Colony growth of Xanthomonas campestris was completely inhibited by 10% leaf extract of Eeucalyptus sp.

Aqueous extract of 5% and 7.5% Eucalyptus sp., Allium sp., and 0.5% Eucalyptus oil reduced Myrothecium leaf spot on par with carbendazim 0.1% in vivo.

Ethanolic extract (5% w/v) of Eucalyptus sp., significantly reduced the bacterial leaf spot severity. Comparative efficacy study revealed that pre treated mulberry plants with Eucalyptus sp. leaf extract (2.5% and 5%), Eucalyptus oil and streptomycin sulphate (0.025) reduced and prevented the disease.

Synergestic effect of Allium sp., Eucalyptus sp., and sub-optimal dose of carbendazim evaluated under inoculated condition showed that the aqueous extract of Allium sp. + Eucalyptus sp. and Eucalyptus sp + Carbendazim reduced Myrothecium leaf spot severity at par with 0.1% Carbendazim. Synergestic effect of Cassia sp. + Azadirachta sp., and individual PE with Bavistin and Sulfex reduced powdery mildew up to  42% with the combination of Cassia sp. (2)+ Sulfex  (2.5%+0.1%) followed by Azadirachta sp. extract + Sulfex (2.5%+0.1%).

 Aqueous essential oil severity fraction from Eucalyptus leaves at 0.75%  (w/v) reduced the Myrothecium leaf spot severity by 48%  21 days after application and at 1% reduced bacterial leaf spot by 56%

Study on various decomposed organic matters tested against Myrothecium leaf spot and powdery mildew under in vitro and in vivo conditions showed that the extracts of decomposed matters such as Moringa sp., Catheranthus sp., Tagetus sp., Eichhornia sp., FYM, silkworm rearing waste  and weed inhibited conidial germination of Phyllactinia corylea by 58.3%, 54.3%, 48.61%, 36.37%, 44.46%, 33.33%, 33.33% respectively. Sterilized extracts were not effective, which confirmed that the microorganism present in the extract have mildew inhibitory property.

Five bacterial strains isolated form mulberry phylloplane showed antagonism to Myrothecium roridum and Phyllactinia corylea and six to Xanthomonas campestris in vitro.

Brevibacterium linens, Bacillus sp. B. megaterium and Serratia marcescens reduced Myrothecium leaf spot severitysignificantly in vivo.

Duplet and triplet combinations of bacterial strains isolated from mulberry phylloplane reduced Myrothecium leaf spot severity.

Individual and duplet combinations of three bacterial strains isolated from decomposed material were effective against Myrothecium leaf spot and all the combinations reduced the disease severity significantly. Individual bacterial strains were found to be more effective in controlling the disease severity from 44.06% to 64.47, while in combinations the disease control efficacy ranged between 32.32 and 39.98%. No synergistic effect of bacterial strains was observed for the control of powdery mildew.

Residual toxicity of five antagonistic phylloplane bacterial strains and four bacterial strains isolated form decomposed material tested on silkworm did not show significant adverse effect on survival, larval weight, larval duration, ERR (No. and Wt.) and SR%.

Growth rate of five selected bacterial strains isolated from mulberry phylloplane studied in four culture media were found to be viable up to 120 days after inoculation. Result indicated that both Myrothecium leaf spot and bacterial leaf spot were controlled by Eucalyptus leaf extract and Eucalyptus oil significantly. And powdery mildew by Cassia tora at par with fungicide/ agriculture antibiotics. Biocontrol agents viz. Bacillus sp. B. pumilus and B. lentimorbus significantly controlled bacterial leaf spot, powdery mildew and myrothecium leaf spot respectively. Disease controlling efficacy of the bacterial strains was at par with the chemical plant protectants.