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ARS Home » Research » Publications at this Location » Publication #67474
Title: OBSERVATIONS ON COMMERCIAL BIOCONTROL MICROFLORA COLONIZATION OF PLANT ROOTS AND EFFICACY OF ROOT DISEASE CONTROL OF PLANTING MIX - PROPAGATED VEGETABLES AND CITRUS IN FLORDIA

Author
item Nemec Jr, Stanley
item DATNOFF, L. - UNIV OF FL. EREC
item STRANDBERG, J. - UNIV. OF FL.

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Tomato, bell pepper, celery and other vegetables as well as citrus are important crops produced in Florida. Production of some of these crops begins in greenhouses, and after becoming established in planting mixes, seedlings are transplanted to the field. Most transplanted vegetables, especially tomato and pepper, are planted in methyl bromide treated soils. Root disease control alternatives are being sought for methyl bromide because it will be phased out of use after 2001. Biological control is one alternative. This study showed that incorporating various commercial sources of biocontrol microflora into planting mixes reduced root diseases of transplanted plants in the field. Trichoderma harzianum reduced tomato crown rot severity an average of 42% and disease incidence an average of 39% compared to the control, over four field tests. Bacillus subtilis was the most effective in reducing Phytophthora caused diseases. These studies are continuing.

Technical Abstract: Tomato, bell pepper, celery, and citrus were propagated in planting mixes amended with formulations of commercial biocontrol microflora. Root colonization by selected microflora was evaluated for pepper, tomato, and citrus and found to be generally between 76 to 100% in both greenhouse ebb and flow and bench-produced plants. Only Glomus intraradices colonization was low, about 8%. All biological controls, Trichoderma harzianum, Bacillus subtilis, G. intraradices, Gliocladium virens, and Streptomyces griseovirdis reduced crown rot of tomato in the field, with T. harzianum and B. subtilis being the most effective uniformly among four tests. Four biocontrols reduced Phytophthora parasitica root rot on citrus in the field, two applied as a drench to soil in pots reduced citrus Thielaviopsis basicola root rot, and two biocontrol agents in combination reduced celery root rot caused by Pythium and Fusarium spp., however, none improved above ground plant growth or health of citrus and celery. Pepper crown and root rot caused by P. capsici was reduced by one biocontrol B. subtilis in one of two tests.