- Author: Surendra K. Dara
There has been a growing interest in the recent years in exploring the potential of biostimulants in crop production. Biostimulants are mineral, botanical, or microbial materials that stimulate natural processes in plants, help them tolerate biotic and abiotic stressors, and improve crop growth and health. Several recent studies demonstrated the potential of the biostimulant or soil amendments in improving crop yields and health. For example, in a 2017 field study, silicon, microbial, botanical and nutrient materials improved processing tomato yields by 27 to 32% compared to the standard fertility program (Dara and Lewis, 2018). In a 2017-2018 strawberry field study, some biostimulant and soil amendment products resulted in a 13-16% increase in marketable fruit yield compared to the grower standard (Dara and Peck, 2018). He et al. (2019) evaluated three species of Bacillus and Pseudomonas putida alone and in different combinations in tomatoes grown in laboratory and greenhouse. The combination of Bacillus amyloliquefaciens, B. pumilus, and P. putida increased the plant biomass and the root/shoot ratio. Significant increase in fruit yield, between 18 and 39%, was also achieved from individual or co-inoculations of these bacteria. A field study was conducted in processing tomato to evaluate the impact of nutrient products containing beneficial microbes and botanical extracts on tomato yields and fruit quality.
The study was conducted from late spring to fall of 2018 to evaluate three treatment programs compared to the grower standard. Tomato cultivar Quali T27 was seeded on 25 April and transplanted on 19 June using a mechanical transplanter. Due to high temperatures at the time of planting, some transplants died and they were re-planted on 28 June. Herbicide Matrix was applied on 5 July and Poast was applied on 13 July followed by hand weeding on 27 July. Crop was irrigated, fertigated, and treatements were applied through a drip system. Overhead sprinkler irrigation was additionally used immediately after transplanting. The following treatments were included in the study:
1. Grower standard: 10-34-0 Ammonium Polyphosphate Solution was applied at 10 gal/ac at the time of transplanting followed by the application of UAN-32 Urea Ammonium Nitrate Solution 32-0-0 at the rate of 15 units of N at 3, 6, and 13 weeks after planting and 25 units of N at 7 weeks after planting.
2. Grower standard + BiOWiSH Crop 16-40-0: BiOWiSH Crop 16-40-0 contains 16% nitrogen and 40% phosphate along with B. amyloliquefaciens, B. licheniformis, B. pumilus, and B. subtilis at 1X108 cfu/gram. Crop 16-40-0 was applied at 1 lb/ac at the time of planting followed by the application 0.5 lb/ac at 3, 6, and 9 weeks after planting.
3. Grower standard 85% + BiOWiSH Crop 16-40-0: Crop 16-40-0 was applied at the same rate and frequency as in treatment 2, but the grower standard was reduced to 85%.
4. RootRx: RootRx contains 5% soluble potash and proprietary botanical extracts and is supposed to stimulate a broad range of antioxidant compounds in the plant. It was applied at 0.25 gal/ac at the time of planting followed by the application of 0.5 gal/ac at 3, about 7, and 13 weeks after planting.
Each treatment contained 30' long bed with a single row of tomato plants and replicated five times in a randomized complete block design. Along with the fruit yield, the sugar content of the fruit and leaves [using a refractometer from three fruits (two measurements from each) and four leaves per plot], chlorophyll content (using a digital chlorophyll meter from four leaves per plot), and frost damage levels (using a visual rating on a 0 to 5 scale where 0 = no frost damage and 5 = extreme frost damage with a complete plant death) were also monitored. Due to an unknown reason, some plants in the fifth replication were stunted halfway through the study. Data from the fifth replication were excluded from the analysis. Data were subjected to the analysis of variance using Statistix software and significant means were separated using the Tukey's HSD test.
Fruit yield: Marketable and unmarketable fruit yield was monitored from 27 August to 13 November. Seasonal total for marketable fruit was significantly (P = 0.04) different among the treatments where RootRx resulted in a 26.5% increase over the grower standard while Crop 16-4-0 with the full rate of the grower standard had an 8%, and with 85% of the grower standard had a 13.2% increase. It appeared that a similar improved yield response was also seen when Crop 16-40-0 was used at a reduced rate of the grower standard in other studies conducted by the manufacturer.
Sugar content: Sugar content of the fruit and leaves was measured once after the last harvest and there were no significant (P > 0.05) difference among the treatments.
Chlorophyll content: Chlorophyll content was measured once after the last harvest and there was no significant (P > 0.05) difference among the treatments.
Frost damage: Study was concluded after frosty conditions in November 2018 damaged the crop. Although there were no statistically significant (P > 0.05) differences, plants treated with RootRx had the lowest rating of 2.
Acknowledgements: Thanks to Jenita Thinakaran and the field staff at the Shafter Research Station for their technical assistance, Plantel Nurseries for providing transplants, and BiOWiSH Technologies and Redox Chemicals for their financial support.
Dara, S. K. and D. Peck. 2018. Microbial and bioactive soil amendments for improving strawberry crop growth, health, and fruit yields: a 2017-2018 study. UCANR eJournal of Entomology and Biologicals (https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=27891)
Dara, S. K. and E. Lewis. 2018. Impact of nutrient and biostimulant materials on tomato crop health and yield. UCANR eJournal of Entomology and Biologicals (https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=26054)
He. Y., H. A. Pantigoso, Z. Wu, and J. M. Vivanco. 2019. Co-inoculation of Bacillus sp. and Pseudomonas putida at different development stages acts as a biostimulant to promote growth, yield and nutrient uptake of tomato. J. Appl. Microbiol. https://doi.org/10.1111/jam.14273
- Author: Surendra K. Dara
- Author: Dave Peck, Manzanita Berry Farms
Various soilborne, fruit and foliar diseases can affect strawberry crop and fruit yields. Chemical fumigants and a variety of fungicides are typically used for managing the disease issues. In addition to the environmental and human health concerns with chemical control options there is a need to improve current disease management with alternatives that include beneficial microbes. Previous studies showed some promise with some of the treatments, but additional studies are required to evaluate the efficacy, which is more evident especially when there is disease incidence.
A study was conducted in summer-planted conventional strawberries in 2016 at Manzanita Berry Farms to evaluate the impact of various beneficial microbial treatments on plant growth, health, and fruit yield. Untreated control and the grower standard practice (Healthy Soil treatment) were compared with MycoApply EndoMaxx (Glomus intraradices, G. aggregatum, G. mosseae, and G. etunicatum), Actinovate AG (Streptomyces lydicus WYEC 108), and Inocucor Garden Solution (Saccharomyces cerevisiae and Bacillus subtilis) applied in the following treatments:
1. Untreated control
2. Grower Standard-Healthy Soil; transplant dip in Switch 62.5WG 5 oz in 100 gal
3. MycoApply EndoMaxx 2 gpa transplant dip (TD)
4. MycoApply EndoMaxx 2 gpa drip at planting (DrP)
5. MycoApply EndoMaxx 2 gpa transplant dip + 2 gpa drip at planting
6. MycoApply EndoMaxx 4 gpa transplant dip
7. MycoApply EndoMaxx 4 gpa drip at planting
8. MycoApply EndoMaxx 4 gpa transplant dip + 4 gpa drip at planting
9. Actinovate AG 6 oz/ac transplant dip + 6 oz drip at planting + 6 oz drip monthly (DrM)
10. Inocucor Garden Solution 1 gpa drip at planting + 1 gpa drip monthly
Transplanting was done on 21 May, 2016 with appropriate treatments administered at the time of planting and thereafter. Study had two blocks of 10 strawberry beds (300' long) and treatments were randomly applied to a bed within each block. Two 15' long plots were marked within each bed for sampling. Canopy growth was measured on June 21, July 5 and 20; powdery mildew severity on August 3, September 1, October 10 and November 16; botrytis severity 3 and 5 days after harvest (DAH) for berries harvested on September 13 and 27, and October 11 and 18; and dead and dying plants were counted on September 16 and October 23. Yield data were collected from August 20 to November 18. Powdery mildew and botrytis fruit rot severity was measured on a scale of 0 to 4 where 0=No disease, 1=1-25%, 2=26-50%, 3=51-75%, and 4=76-100% severity. Data were analyzed and means were separated using LSD test.
Strawberry field and plots on June 9 (above) and August 31 (below).
Two sampling plots were set up within each bed to collect plant growth, health, and yield data.
Canopy growth: MycoApply EndoMaxxat 2 gpa either as a transplant dip with or without drip application at planting appeared to promote significantly higher growth (P <0.0001) than MycoApply EndoMaxx at 2 and 4 gpa as drip at planting, untreated control, and grower standard. Inoculating the entire transplant with Glomus spp. through a dip appears to be better than application through drip irrigation system.
Powdery mildew: Disease incidence and severity was low during the observation period. When the average of four observations period was compared, the grower standard, MycoApply Endomaxx at 2 and 4 gpa as drip at planting, and the Actinovate treatments had the lowest incidence (P = 0.0271).
Botrytis fruit rot: There was no difference (P >0.05) among the treatments on botrytis when the mold growth on fruit was compared 3 and 5 days after harvest.
Unknown issue: Some wilting and dead plants were found throughout the field during the study. Although symptoms suggested some kind of wilt, laboratory testing did not identify any pathogens. The total number of dead and dying plants was the lowest in Actinovate treatment, but it was significantly different (P = 0.0429) only from the grower standard Healthy Soil treatment.
*Means followed by the same or no letter are not significantly different at the P value indicated in the table.
Fruit yield: There were no statistically significant difference among the treatments and the seasonal total of marketable yield varied between 66 lb/plot in the grower standard and about 76 lb/plot in MycoApply EndoMaxx applied as a transplant dip at 4 gpa.
Total and marketable berry yields and their proportion among different treatments.
We need to continue to evaluate beneficial microbial products and their potential benefit in improve crop health and yields.
Acknowledgements: Thanks to Chris Martinez and Tamas Zold for technical assistance, and Valent USA and Inocucor Technologies for the financial support of the study.