Strawberry and vegetable crops extension program and its impact in San Luis Obispo and Santa Barbara Counties
Extension education plays a major role in agricultural development. Timely and efficient dissemination of information on new technologies, crop production or pest management practices, and emerging or potential problems helps growers to reduce their production costs and improve yields. A variety of communication tools and techniques are necessary to effectively carry out the mission of extension education. As communication is a major part of extension education, the kind of communication tools used will determine the success of the program. Modern communication tools such as emails, webinars, electronic journals, social media, web portals, videos, and smartphone applications add value to traditional outreach methods such as field visits, phone calls, extension meetings, and field days. While the number of subscribers, views to online articles, or attendees at meetings indicates the effectiveness of the extension program, periodic surveys are very important to measure the impact.
Here is an overview of my extension program and some of the methods used to reach out to my clientele groups since I joined UC Cooperative Extension in January, 2009.
Field visits or individual consultations: They provide an opportunity to understand individual needs and provide specific solutions. More than 6,300 people have been served through personal visits or communication related to various crop production and crop protection.
Field days and extension meetings: My annual extension events provide an excellent opportunity to bring together local communities where new information is exchanged and collaborations are developed. I have reached out to more than 5,800 people through various extension events organized by myself, my colleagues, or industry partners. Presentations and handouts from my meetings can be accessed online.
Trade journals and web portals: Several print magazines and web portals such as American Vegetable Grower, American Fruit Grower, CAPCA Adviser, Growing Produce, Vegetables West, and Western Farm Press are excellent resources to disseminate information to thousands of readers. I regularly contribute article to these sources.
Newsletters: Sending out periodical information through newsletters keeps the clients informed about new developments. Central Coast Agriculture Highlights is a quarterly newsletter that I sent out to about 500 subscribers. After finding out that other online articles are more effective in timely dissemination of information, I focused more on those options. However, I continue to contribute articles to county newsletters.
Electronic journals: I started the electronic journal Strawberries and Vegetables six years ago (15 December, 2010), to alert growers about an issue that some of the strawberry growers were experiencing. Most of these articles are reviewed by peers and their periodic publication allowed immediate availability of information to people within the region as well as those outside California or United States. I started another electronic journal Pest News in January, 2011, to provide information about pests, diseases, and other issues not related to strawberries and vegetables.
Out of the 80 articles in Strawberries and Vegetables, I authored or co-authored 74. These articles have a total of 173,120 direct views between 15 December, 2010 and 2016. While my 74 articles had 168,469 views, the remaining six had 4,651. On an average, each of my articles was read more than 2,200 times.
Readership of Strawberries and Vegetables eJournal related to specific crops or general issues from 15 December 2010-2016. Numbers on the bars are the number of articles.
Number of articles (on bars) on different topics and their readership from 15 December, 201-2016 (above). Top five articles with the highest number of views (below).
The average views for articles on strawberry or vegetable issues was about the same, but when the views or the readership of individual articles was considered, spider mite management in strawberries was the most popular topic followed by information on the invasive Bagrada bug.
In Pest News the 16 articles I authored or co-authored were viewed 52,743 times since 2 February, 2011 while the 15 article authored by others were viewed 15, 264 times. Articles about the spotted lanternfly the weeping fig thrips, both invasive species, had the highest views.
Top five popular articles in Pest News eJournal.
Other extension publications: The illustrated strawberry production manual published in collaboration with Cachuma Resource Conservation District in both English and Spanish is available for free download. This publication complements contributions made to pest management guidelines or manuals published by UCANR.
Smartphone application: Apps have become very popular because of the convenience and a variety of features or services they offer. I conceived the idea of developing IPMinfo app three years ago to provide information about pests and diseases and had an Android version developed first for initial testing. An iOS version was first released in May, 2015 and with some improvements, the Android version was released in September, 2016. IPMinfo currently has information about strawberry pests and diseases, but additional crops will be added. With a few hundred downloads and very positive feedback from several users, IPMinfo, the first such app from University of California is an efficient extension tool using modern technology.
IPMinfo can be downloaded through Apple App Store and Google Play Store for free.
Twitter:Tweets are a great way to announce publications, extension events, or important issues in 140 characters or less. I started @calstrawberries and @calveggies accounts in January, 2010, which now have 210, and 149 followers, respectively. In addition to the followers, tweets from these accounts reach out to hundreds of other Twitter users.
Stay tuned to the updates by following @calstrawberries and @calveggies.
Facebook: Not having the character limit as in Twitter, Facebook allows us to post pictures and large text to engage clients in conversation about research and extension activities. I created the @strawberriesvegetables page in June, 2012 and it reaches out to those who are not connected through other tools.
Like the @strawberriesvegetables Facebook page and stay connected.
YouTube videos: A picture is worth a thousand words and a video is worth much more. Short videos are very valuable in providing information or training on a variety of issues. I first posted a YouTube video on the biology, damage, and control of the Bagrada bug on 1 August, 2013 in response to numerous queries about this invasive pest. On 23 September, 2013, I posted my second video on virus decline (Pallidosis-related decline) of strawberry. Both videos helped in providing a good overview of important issues at that time. Additional videos are also available on my YouTube channel.
Informative short videos on pest and disease issues can be found on my YouTube channel.
While there are several communication tools for extending information, it is important to evaluate the advantages and disadvantages of each and use them as appropriate for the program and the specific clientele groups.
Needs assessment and impact measurement: Assessing the needs of the clients helps build a research and extension program that addresses existing and emerging issues. Conducting surveys immediately and a few months after the extension events helps understand their usefulness and impact in improving clients' knowledge, change behavior, or improving their agricultural practices. Surveys conducted after my extension events have been receiving positive feedback. For example, a recent survey showed that the information I provided through my research and extension program during last year positively impacted farming on more than 137,000 acres and improved savings or returns that amounted to $1.28 million.
Feedback received from more than 300 people since 1 September, 2015 indicated that 99.4% found the articles in my electronic journals useful and 93.4% would use that information in their farming operations.
Highly positive feedback indicates the usefulness of the information provided through the two eJournals.
Acknowledgements: Thanks to all the growers, PCAs, industry partners, and other clients who support my research and extension program and continue to provide feedback enabling me to improve and serve better.
Synthetic or chemical or inorganic fertilizers are commonly used in many conventional crop production systems providing essential nutrients necessary for optimal plant growth and yields. While these fertilizers provide plants with readily available nutrients, excessive application could lead to leaching into the ground water or increase the attractiveness of plants to pests and diseases. Organic fertilizers, on the other hand, are generally made from plant or animal sources. Compared to synthetic fertilizers where nutrients are readily available, nutrients are slowly released from organic fertilizers and thus have a lower risk of nutrient leaching. Organic fertilizers add organic matter to the soil, which improves soil structure, water holding capacity, and root growth. Organic matter also supports beneficial microbial communities in the soil that improve nutrient availability to the plant and protect plants from plant pathogens and other stress factors.
Organic fertilizers, especially those made from food waste, have a significant environmental benefit by recycling valuable nutrient and energy resources that would have, otherwise, been wasted (Senesi, 1989). Several studies emphasized the importance of soil organic matter and its positive impact on soil fertility, crop productivity, and environmental sustainability (Tisdall and Oades, 1982; Baldock and Nelson, 2000; Johnston et al., 2009). However, a balanced used of both synthetic and organic fertilizers is a good strategy both to meet plant needs and environmental sustainability (Chen, 2006).
In the United States, food waste at consumer and retail levels was estimated to be about 30% of the food supply, which is equal to 133 billion pounds valued at $161 billion (USDA-ERS, 2016). Food waste is the largest part what goes into landfills and is the third largest source of methane in the United States. Converting food waste into a fertilizer will have a major impact on agriculture and environment.
To evaluate the efficacy of a recycled food waste-based liquid compost on strawberry yield, a study was conducted during the spring of 2013 on a conventional strawberry field at DB Specialty Farms, Santa Maria.
Materials and Methods
Harvest-to-Harvest (H2H), made by hydrolysis of freshly expired produce, meat, and other food items collected from grocery stores, was evaluated alone and in combination with the grower standard. The formulation of H2H used in the study had NPK at 1-1-0, 5-7% of amino acids, 6-8% of lipids, 8-10% carbohydrates, and 20-25% organic matter according to the label. Treatments included i) Grower standard or GS (proprietary fertilizer regimen), ii) H2H at 73 gallons/acre, and iii) H2H:GS at 50:50. H2H was administered through the drip irrigation system 28 March, 9 and 18 April. Each treatment had a block of about 1.6 acre that were adjacent to each other. On six randomly selected beds within each block, a 40-plant section was marked as a sampling plot. Yield data were collected from these plots from 4 April to 20 May on 10 sampling dates following grower's harvest schedule.
Data were analyzed using analysis of variance and significant means were separated using Tukey's HSD test.
Andres Tapia administering treatments through a special pump built by Joe Coelho (above) and observation plots (below).
Results and Discussion
Compared to the yield in GS plots, marketable strawberry yield was significantly higher (P < 0.05) for H2H treatment on four of the harvest dates and for GS:H2H combination on two of the harvest dates (Table 1). The average marketable berry yield was significantly higher (P = 0.0003) in both H2H and GS:H2H treatments compared to the GS treatment (Fig. 1). There was no difference (P = 0.283) in the weight of unmarketable berries and their proportion of the total yield was 18.7, 15.5, and 16.2 for GS, H2H, and GS:H2H, respectively.
Table 1. Marketable berry yield on different harvest dates. Means followed by the same letter within the same column are not statistically different based on Tukey's HSD test.
Fig. 1. Average marketable and unmarketable yield during the observation period.
This first commercial field study using H2H shows promising results in improving strawberry yield with recycled food waste. Manufacturer made changes to the H2H formulation and recommendation rates after the study was conducted. Additional studies in different fields with different application rates from the beginning of the production season are essential to make valid conclusions. Soil conditions and nutrient management practices vary among various fields and additional studies will add value to the results obtained in this preliminary study.
Acknowledgements: Thanks to Daren Gee for the collaboration, California Safe Soils for financial support, and Joe Coelho and Andres Tapia for their technical assistance.
Baldock, J. A. and P. N. Nelson. 2000. Soil organic matter. In: Sumner, M. E. (Ed.) Handbook of Soil Science. CRC Press, Boca Raton, FL, USA, pp. B25-B84.
Chen, J.-H. 2006. The combined use of chemical and organic fertilizers and/or biofertilizer for crop growth and soil fertility. International workshop on sustained management of the soil-rhizosphere system for efficient crop production and fertilizer use. Vol. 16. p. 20. Land Development Department Bangkok, Thailand.
Johnston, A. E., P. R. Poulton, and K. Coleman. 2009. Soil organic matter: its importance in agriculture and carbon dioxide fluxes. Adv. Agronomy 101: 1-57.
Senesi, N. 1989. Composted materials as organic fertilizers. Science of the Total Environment 81: 521-542.
Tisdall, J. M. and J. M. Oades. 1982. Organic matter and water-stable aggregates in soils. European J. Soil Sci. 33: 141-163.
United States Department of Agriculture Economic Research Service (USDA-ERS). 2016. US Food Waste Challenge FAQ's. Accessed on 9 December, 2016 from http://www.usda.gov/oce/foodwaste/faqs.htm
Six-month old strawberry field.
Under the soil is a complex and dynamic world of moisture, pH, salinity, nutrients, microorganisms, and plant roots along with pests, pathogens, weeds and more. A good balance of essential nutrients, moisture, and beneficial microorganisms provides optimal plant growth and yield. These factors also influence natural plant defenses and help withstand stress caused by biotic and abiotic factors.
Several beneficial microbe-based products are commercially available to promote plant growth and improve health, yield potential and quality. Some of them improve nutrient and water absorption while others provide protection against plant pathogens or improve plant defense mechanism. In addition to the macronutrients such as nitrogen, phosphorus, and potassium, several micronutrients are critical for optimal growth and yield potential. Some of the micronutrient products are also useful in promoting beneficial microbes. Understanding the plant-microbe-nutrient interactions and how different products help crop production are helpful for making appropriate decisions.
Mycorrhizae (fungi of roots) establish a symbiotic relationship with plants and serve as an extended network of the root system. They facilitate improved uptake of moisture and nutrients resulting in better plant growth and yield (Amerian and Stewart, 2001; Wu and Zou, 2009; Bolandnazar et al., 2007; Nedorost et al., 2014). Mycorrhizae can also help absorb certain nutrients more efficiently than plants can and make them more readily available for the plant. With increased moisture and nutrient absorption, plants can become more drought-tolerant. Mycorrhizae also help plants to withstand saline conditions and protect from plant pathogens. A healthy root system can fight soil diseases and weed invasion. Additionally, mycorrhizae increase organic matter content and improve soil structure.
Considering an increasing need for fumigation alternatives to address soilborne pathogens in strawberry, mycorrhizae and other beneficial microbes could be potential tools in maintaining plant health. Additionally, recent studies suggest that entomopathogenic fungi such as Beauveria bassiana, Metarhizium brunneum, and Isaria fumosorosea form mycorrhiza-like and endophytic relationships with various species of plants and could help with plant growth and health (Behie and Bidochka, 2014; Dara et al., 2016). These fungi are currently used for pest management, but their interaction with plants is a new area of research. Understanding this interaction will potentially expand the use of the biopesticides based on these fungi for improving plant growth and health. A study was conducted at Manzanita Berry Farms, Santa Maria in fall-planted strawberry crop during the 2014-2015 production season to evaluate the impact of beneficial microbes on strawberry growth, health, mite infestations, powdery mildew, botrytis fruit rot, and yield.
List of treatments, their application rates and frequencies:
- Untreated control: Received no supplemental treatments other than standard grower practices.
- HealthySoil: NPK (0.1-0.1-0.1).
- BotaniGard ES: Entomopathogenic fungus Beauveria bassiana strain GHA. Rate - 1 qrt in 50 gal for a 30 min transplant dip and 1 qrt/ac every 15 days until January and once a month thereafter until April, 2015.
- Met52: Entomopathogenic fungus Metarhizium brunneum strain F52. Rate – 16 fl oz in 50 gal for a 30 min transplant dip and 16 fl oz/ac every 15 days until January and once a month thereafter until April, 2015.
- NoFly: Entomopathogenic fungus Isaria fumosorosea strain FE9901. Rate – 11.55 oz in 50 gal for a 30 min transplant dip and 11.55 oz/ac every 15 days until January and once a month thereafter until April, 2015.
- Actinovate AG: Beneficial soilborne bacterium Streptomyces lydicus WYEC 108. Rate – 6 oz in 50 gal for a 30 mintransplant dip and 6 oz/ac every month.
- TerraClean 5.0: Hydrogen dioxide and peroxyacetic acid. Rate – 1:256 dilution for a 1 min root dip followed by 2 gal/ac 10 days after planting and then 2 and 1 gal/ac alternated every 15 days until April, 2015.
- TerraGrow: Humic acids, amino acids, sea kelp, glucose based carriers, bacteria – Bacillus licheniformis, B. subtilis, B. pumilus, B. amyloliquefaciens, and B. magaterium, and mycorrhizae – Trichoderma harzianum and T. reesei. Rate – 1.13 g in 10 gal for a 1 min root dip followed by 1.5 lb/ac 10 days after planting and once every month until April, 2015.
- TerraCelan and TerraGrow: Same as individual treatments at the time of planting, but TerraClean at 2 gal/ac and TerraGrow at 1.5 lb/ac 10 days after planting followed by monthly treatments until April, 2015.
- O-MEGA: NPK (0.2-1.0-0.5), bacteria – Azotobacter chroococcum, Azospirillum lipoferum, Lactobacillus acidophilus, Pseudomonas fluorescens, Cellulomonas cellulans and the fungus Aspergillus niger. Rate – 20 ml in 1 gal sprinkled on transplants 30 min before planting followed by 1 qrt/ac every week rest of the season.
Strawberry transplants (variety BG-6.3024) were treated at the time of planting on 6 November, 2014 and treatments are also administered periodically through the drip irrigation system following the abovementioned schedule. Each treatment had two 330' long beds each with four rows of plants. Treatments were randomly arranged in two blocks and two sampling plots (20' long) were established within each bed in a block. The impact of the treatments on plant growth (canopy size), health, spider mite populations, botrytis and powdery mildew severity, and yield were monitored periodically. Plant growth was determined by measuring the canopy size. Plant health was rated on a scale of 0 to 5 where 0=dead, 1=weak, 2=moderate low, 3=moderate high, 4=good, and 5=very good. Powdery mildew severity was determined by observing leaf samples under microscope and rating the severity on a scale of 0 to 4 where 0=no infection, 1=1-25%, 2=26-50%, 3=51-75%, and 4=76-100% of leaf area with powdery mildew. Twenty plants or leaf samples per plot were used for these observations. To monitor botrytis fruit rot, a box of fruits from each plot were held at room temperature and disease was rated 3 and 5 days after harvest on a scale of 0 to 4 where 0=no infection, 1=1-25%, 2=26-50%, 3=51-75%, and 4=76-100% of fruit with botrytis. Yield data were also collected from the plots throughout the production season using grower's harvesting schedule. Mite counts were also taken periodically.
Data were analyzed using analysis of variance and significant means were separated using Tukey's HSD means separation test.
Treating the transplants with different treatment materials and planting in respective beds
Newsly transplanted experimental plots.
Chris Martinez (center, front row) and rest of the field crew at Manzanita Berry Farms
Canopy size: Significant differences (P = 0.002) among treatments were seen only on the first observation date on 26 January, 2015 where TerraClean-treated plants were smaller than some of the treatments. There were no significant differences (P > 0.05) in treatments on the following observations in February and March, however TerraClean-treated plants recovered and plants were larger in some of the treatments.
Size of the plant canopy on three observation dates.
Plant health: Treatments did not have a significant (P > 0.05) impact on plant health. Health ratings varied from 4.2 for TerraClean to 4.6 for untreated, BotaniGard, Actinovate, and O-Mega treatments in January. In February, TerraGrow-treated plants had 4.5 rating and BotaniGard and O-Mega treatments had 4.8. March ratings varied between 4.8 and 4.9 in all the treatments. As there were no soilborne diseases during the study period, the impact of the treatments could not be determined, which was the main objective of the study.
Plant health ratings on three observation dates.
Powdery mildew: Disease severity did not differ among treatments (P > 0.05) on 16 April and 16 June, but significant (P = 0.008) differences were observed on 26 June where BotaniGard-treated plants had the lowest. When data were compared for the three observation dates, severity rating varied from 1.8 for BotaniGard to 2.24 for TerraClean.
Powdery mildew severity on individual observation dates (top) and combined for three observations (bottom)
Botrytis fruit rot: There were no significant (P > 0.05) differences among treatments on any of the four observation dates or when data were combined for all observations. In general, fruit rot was less severe 3 days after harvest than 5 days after during the first three observation dates. When data were combined for the observation dates, HealthySoil treatment had a rating of 1 followed by Met52, NoFly, Actinovate, and TerraClean+TerraGrow with a 1.3 rating for 3 days after harvest.
Severity of botrytis fruit rot 3 and 5 days after harvest on individual observation dates (above) and when data were combined (below).
Spider mites: Mite populations were very low in all the plots during observation period and data were not included.
Fruit yield: While the seasonal yield of total, marketable, or unmarketable berries was not significantly (P > 0.05) different for any of the treatments marketable yields had a wider range than unmarketable yields among treatments. The lowest marketable fruit yield was seen in TerraClean (35.6 kg or 79.4 lb) and HealthySoil (35.8 kg or 79.8 lb) while the highest yield was seen in Actinovate (40.1 kg or 89.4 lb) followed by untreated control (39.4 kg or 87.9 lb), O-Mega (39.3 kg or 87.6 lb), Met52 (39.2 kg or 87.4 lb), and NoFly (38.7 kg or 86.3 lb) treatments.
Seasonal yields of total, marketable, and unmarketable strawberries per plot.
This is the first field study evaluating the impact of three popular entomopathogenic fungi along with multiple beneficial microbes on strawberry plant growth, foliar and fruit diseases, and yield. While differences among treatments were not pronounced, it appeared that some had a positive impact on some of the parameters measured. It is interesting to note that yields were higher (although not statistically significant) than the grower standard, HealthySoil. Compared to the grower standard, marketable yield was higher in many other treatments. Since an untreated situation is not common in a commercial field, using beneficial microbes can be useful. Although previous field studies evaluated the impact of with the entomopathogenic fungus B. bassiana in strawberries (Dara, 2013; Dara, 2016), a positive impact on plant growth or yield by I. fumosorosea and M. brunneum in commercial strawberries has never been reported earlier.
Additional studies with different application rates would be useful to understand how beneficial microbes could be exploited more.
Acknowledgments: Thanks to Dave Peck, Manzanita Berry Farms for the collaboration and industry partners for the financial support. Thanks to Chris Martinez and rest of the field crew at Manzanita Berry Farms and Fritz Light and Tamas Zold for the technical assistance.
Amerian, M.R., and W.S. Stewart. 2001. Effect of two species of arbuscular mycorrhizal fungi on growth, assimilation and leaf water relations in maize (Zea mays). Aspects of Appl. Biol. 63: 1-6.
Behie, S.W., and M.J. Bidochka. 2014. Nutrient transfer in plant-fungal symbioses. Trends in Plant Sci. 19: 734-740.
Bolandnazar, S., N. Aliasgarzad, M.R. Neishabury, and N. Chaparzadeh. 2007. Mycorrhizal colonization improves onion (Allium cepa L.) yield and water use efficiency under water deficit condition. Sci. Horticulturae 114: 11-15.
Dara, S. K. 2013. Entomopathogenic fungus Beauveria bassiana promotes strawberry plant growth and health. UCANR eJournal Strawberries and Vegetables, 30 September, 2013. (http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=11624)
Dara, S. K. 2016. First field study evaluating the impact of the entomopathogenic fungus Beauveria bassiana on strawberry plant growth and yield. UCANR eJournal Strawberrries and Vegetables, 7 November, 2016. (http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=22546)
Dara, S. K., S.S.R. Dara, and S. S. Dara. 2016. First report of entomopathogenic fungi, Beauveria bassiana, Isaria fumosorosea, and Metarhizium brunneum promoting the growth and health of cabbage plants growing under water stress. UCANR eJournal Strawberries and Vegetables, 16 September, 2016.(http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=22131)
Nedorost, L., J. Vojtiskova, and R. Pokluda. 2014. Influence of watering regime and mycorrhizal inoculation on growth and nutrient uptake of pepper (Capsicum annuum L.). VII International symposium on irrigation of horticultural crops, Braun P., M. Stoll, and J. Zinkernagel (eds). Acta Horticulturae 1038:559-564.
Wu, Q.S., and Y. Zou. 2009. Mycorrhizal influence on nutrient uptake of citrus exposed to drought stress. Philippine Agri. Scientist 92: 33-38.
USDA Announces Streamlined Guaranteed Loans and Additional Lender Category for Small-Scale Operators
USDA recently announced the availability of a streamlined version of USDA guaranteed loans, which are tailored for smaller scale farms and urban producers. The program, called EZ Guarantee Loans, uses a simplified application process to help beginning, small, underserved and family farmers and ranchers apply for loans of up to $100,000 from USDA-approved lenders to purchase farmland or finance agricultural operations.
These EZ Guarantee Loans will help beginning and underserved farmers obtain the capital they need to get their operations off the ground, and they can also be helpful to those who have been farming for some time but need extra help to expand or modernize their operations. USDA's Farm Service Agency has offices in nearly every county in the country.
USDA also unveiled a new category of lenders that will join traditional lenders, such as banks and credit unions, in offering USDA EZ Guarantee Loans. Microlenders, which include Community Development Financial Institutions and Rural Rehabilitation Corporations, will be able to offer their customers up to $50,000 of EZ Guaranteed Loans, helping to reach urban areas and underserved producers. Banks, credit unions and other traditional USDA-approved lenders, can offer customers up to $100,000 to help with agricultural operation costs.
EZ Guarantee Loans offer low interest rates and terms up to seven years for financing operating expenses and 40 years for financing the purchase of farm real estate. USDA-approved lenders can issue these loans with the Farm Service Agency (FSA) guaranteeing the loan up to 95 percent.
California Farmlink is one of the USDA-approved lenders for some of these loans: http://www.californiafarmlink.org/farm-financing
FSA also offers loans of up to $5,000 to young farmers and ranchers though the Youth Loan Program. Loans are made to eligible youth to finance agricultural projects, with almost 9,000 young people now participating.
More information about the available types of FSA farm loans can be found at www.fsa.usda.gov/farmloans or by contacting your local FSA office. To find your nearest office location, visit http://offices.usda.gov.
First field study evaluating the impact of the entomopathogenic fungus Beauveria bassiana on strawberry plant growth and yield
Beauveria bassiana is a soilborne entomopathogenic fungus which offers plant protection as a pathogen of arthropod pests (Feng et al., 1994; Dara, 2015). It also appears to have a direct association with plants as an endophyte, colonizing various plant tissues, or through a mycorrizha-like relationship promoting plant health and growth (Bing and Lewis, 1991; Posada and Vega, 2005; Dara, 2013; Dara and Dara, 2015; Lopez and Sword, 2015; Dara et al., 2016;). In a raised bed study conducted in 2013, treating strawberry transplants with B. bassiana resulted in a significant improvement in the plant growth compared to untreated control or treatment with a beneficial microbe-based product (Dara, 2013). To evaluate such an impact in a commercial strawberry field, a study was conducted at Manzanita Berry Farms in Santa Maria in conventional fall-planted strawberries.
Chris Martinez, Manzanita Berry Farms applying B. bassiana to newly planted strawberry crop.
Experimental design included five plots each of the grower standard and periodical soil application of B. bassiana (BotaniGard ES) alternated on consecutive beds. Each plot had 50 strawberry plants. Strawberry variety PS3108 was planted on 27 November, 2013 and B. bassiana treatment was initiated on 2 December, 2013. To prepare the treatment liquid, 0.64 fl oz (18.9 ml) of BotaniGard ES was mixed in 1 gal (3.78 L). About 0.4 fl oz (11.8 ml) of the liquid was applied near the base of each plant (5 cm deep and 2.5 cm away from the plant) in B. bassiana treatment using a handpump sprayer. Application was continued every week until 13 January, 2014 (a total of seven times) followed by six biweekly applications until 7 April, 2014.
To determine the impact of B. bassiana on plant growth, size of the strawberry canopy was measured across and along the length of the bed from every third plant (20 total) within each plot on 21 January, 11 February, and 7 March, 2014. Yield data were collected every 2-3 days from 8 March to 30 June, 2014 following the normal harvest schedule. Data were analyzed using analysis of variance and Tukey's HSD test was used to separate significant means.
Chris Martinez taking canopy measurements.
Canopy size was slightly higher for B. bassiana-treated plants on the first two sampling dates and for the grower standard plants on the last observation date although differences were not statistically significant (P > 0.05). Seasonal total for the marketable berries was slightly higher in the grower standard (101.1 lb or 45.9 kg) than in B. bassiana treatment (44.2 lb or 97.4 kg), but the difference was not statistically significant (P > 0.05). The average weight of marketable berries was 28.8 g from the B. bassiana-treated plots and 28.7 g from the grower standard.
Strawberry canopy (above) and seasonal yield (below) data in B. bassiana-treated and grower standard plots.
In the 2013 raised bed study, roots of the misted tip strawberry transplants were treated 48 hours before planting by applying 1 ml of the Mycotrol-O formulation (2.11X1011 conidia) in 1 ml of water per plant. In the current study, transplants could not be treated before planting and the commercial field application rate used (1.25X109 conidia) was much less than the rate used in the raised bed study. Although multiple applications were made for several weeks during the current study, B. bassiana did not have any impact on plant growth or fruit yields. This was the first commercial field study evaluating the impact of B. bassiana on strawberry plant growth and yield. Plant, soil, and microbe interaction is very complex and is influenced by multiple factors. Additional studies are necessary to understand the potential of B. bassiana and other entomopathogenic fungi in plant production in addition to its role in plant protection.
Acknowledgements: Thanks to Dave Peck, Manzanita Berry Farms for collaboration on the study and Chris Martinez for his technical assistance.
Bing, L. A., and L. C. Lewis. 1991. Suppression of Ostrinia nubilalis (Hübner) (Lepidoptera: Pyralidae) by endophytic Beauveria bassiana (Balsamo) Vuillemin. Environ. Entomol. 20: 1207-1211.
Dara, S. K. 2013. Entomopathogenic fungus Beauveria bassiana promotes strawberry plant growth and health. UCANR eJournal Strawberries and Vegetables, 30 September, 2013.
Dara, S. K. 2016. IPM solutions of insect pests in California strawberries: efficacy of botanical, chemical, mechanical, and microbial options. CAPCA Adviser 19 (2): 40-46.
Dara, S. K. and S. R. Dara. 2015. Entomopathogenic fungus Beauveria bassiana endophytically colonizes strawberry plants. UCANR eJournal Strawberries and Vegetables, 17 February, 2015.
Dara, S. K., S.S.R. Dara, and S. S. Dara. 2016. First report of entomopathogenic fungi, Beauveria bassiana, Isaria fumosorosea, and Metarhizium brunneum promoting the growth and health of cabbage plants growing under water stress. UCANR eJournal Strawberries and Vegetables, 19 September, 2016.
Feng, M. G., T. J. Poprawski, and G. G. Khachatourians. 1994. Production, formulation and application of the entomopathogenic fungus Beauveria bassiana for insect control: current status. Biocon. Sci. Tech. 4: 3-34.
Lopez, D. C. and G. A. Sword, G. A. 2015. The endophytic fungal entomopathogens Beauveria bassiana and Purpureocillium lilacinum enhance the growth of cultivated cotton (Gossypium hirsutum) and negatively affect survival of the cotton bollworm (Helicoverpa zea). Biol. Control 89: 53-60.
Posada, F. and F. E. Vega. 2005. Establishment of the fungal entomopathogen Beauveria bassiana (Ascomycota: Hypocreales) as an endophyte in cocoa seedlings (Theobroma cacao). Mycologia 97: 1195-1200.