Field trials of Naturally Occurring  Soil Microbials to combat HLB

Field trials of Naturally Occurring Soil Microbials to combat HLB

Report Date: 01/01/2016
Project: 928.4   Year: 2015
Category: ACP Vector
Author: Nian Wang
Sponsor: Citrus Research and Development Foundation

This is a 3 year study to provide a side-by-side comparison of 5 soil-applied commercially available products as well as an organic mulch as recommended by growers. The impact of treatments on tree health, foliar nutrition, disease rating, HLB status, root density, yield and fruit quality will be evaluated. Trials will be located in 3 Florida sites: Central Ridge, East Coast and Southwest and will incorporate well-managed trees with HLB but that are as healthy as possible. Each trial will be large enough to be statistically significant with treatments within label guidelines to avoid need for crop destruct or permitting. Objectives of the Project: Test 5 soil-applied products, with mulch subplots, plus an untreated control (6 treatment plots) on health and HLB status of orange trees over 3 years. The 6 treatment plots of 20 trees each will be replicated 4 times plus mulch subplots at the 3 sites will include: 1. BioFlourish (Triangle Chemical).3 applications per year; 2. Ecofriendly Citrus Soil Amendment. 8 x per year; 3. Serenade Soil (Bayer CropScience) 3 x per year; 4. Aliette (Bayer CropScience) 3 x per year 5. Quantum product line 12 x per year; 6. Untreated control (3 mulched trees only 1/year) Our responsibility is to analyze microbe products, analyze root mass, Las in the root, survival or colonization of microbes in the roots, and indicator strains of microbial diversity in the soil. Totally 5 products, including Bioflourish, Ecofridendly citrus soil amendment, serenade soil, aliette and quantum product were involved. The bacteria ingredients in the product Bioflourish and Ecofridendly citrus soil amendment were determined. There were several Lactobacillus species in Bioflourish, and Bacillus subtitis was detected in Ecofridendly citrus soil amendment. The bacteria in serenade soil and quantum product were mentioned by the producer and thus not tested in lab. The field trails were carried out at three sites around Florida (south west, central ridge and east coast) as described by the proposal. The root density was determined in December 2014. Roots were extracted from 500 cc aliquant of each soil sample over a 2 mm mesh sieve by hand. The dry weight of roots was measured. There were totally 504 samples (3 sites*6 treatments*4replicates*7 trees). The average root mass was 1.14 g/500 cc soil. The root mass did not show any significant difference between treatments, neither for each site nor pulled together (ANOVA, P>0.05). When mulch treatments were taken into account, the results suggested mulched treated trees tended to have higher root mass, but not significant (ANOVA, P>0.05).

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