To be held at our office at 1430 Freedom Blvd, Suite E in Watsonville on October 24. Sign in starts at 730 am and the meeting goes to noon.
Get here early, looks to be a pretty heavily subscribed event. Agenda below.
Preliminary report on the potential of Beauveria bassiana and Metarhizium anisopliae s.l. in antagonizing the charcoal rot causing fungus Macrophomina phaseolina in strawberry>
Charcoal rot, caused by Macrophomina phaseolina, is one of the important fungal diseases of strawberry in California. Macrophomina phaseolina is a soilborne fungus and has a wide host range, including alfalfa, cabbage, corn, pepper, and potato, some of which are cultivated in the strawberry production areas in California. The fungus infects the vascular system of the plant roots, obstructing the nutrient and water supply and ultimately resulting in stunted growth, wilting, and death of the plant. The fungus survives in the soil and infected plant debris as microsclerotia (resting structures made of hyphal bodies) and can persist for up to three years. Microslerotia germinate and penetrate the root system to initiate infection. Plants are more vulnerable to fungal infection when they are experiencing environmental (extreme weather or drought conditions) and physiological (heavy fruit bearing) stress.
Soil fumigation is the primary management option for addressing charcoal rot in strawberry. Crop rotation with broccoli can also reduce the risk of charcoal rot due to glucosinolates and isothiocyanates in broccoli crop residue that have fungicidal properties. Beneficial microorganisms such as Bacillus spp. and Trichoderma spp. are also considered, especially in organic strawberries, to antagonize M. phaseolina and other soilborne pathogens and provide some protection. The role of beneficial microbes in disease management or improving crop growth and health is gaining popularity in the recent years with the commercial availability of biofungicide, biostimulant, and soil amendment products. In a couple of recent strawberry field studies in Santa Maria, some of the beneficial microbial products improved fruit yield or crop health. These treatments can be administered by inoculating the transplants prior to planting, immediately after planting or periodically applying to the plants and or the soil. Adding beneficial microbes can help improve the soil microbiome especially after chemical or bio-fumigation and anaerobic soil disinfestation.
Similar to the benefits of traditionally used bacteria (e.g., Bacillus spp. and Pseudomonas spp.) and fungi (e.g., Glomus spp. and Trichoderma spp.), studies with entomopathogenic fungi such as Beauveria bassiana, Isaria fumosorosea, and Metarhizium spp. also demonstrated their role in improving water and nutrient absorption or antagonizing plant pathogens. The advantage of entomopathogenic fungi is that they are already used for arthropod pest management in multiple crops, including strawberry; now, there are the additional benefits of promoting crop growth and antagonizing plant pathogens. In light of some promising recent studies exploring these roles, a study was conducted using potted strawberry plants to evaluate the efficacy of two California isolates of Beauveria bassiana and Metarhizium anisopliae s.l. and their application strategies against M. phaseolina.
About 6 week old strawberry plants (cultivar Albion) from a strawberry field at the Shafter Research Station were transplanted into 1.6-gallon pots with Miracle-Gro All Purpose Garden Soil (0.09-0.05-0.07 N-P-K) and maintained in an outdoor environment. They were regularly watered, and their health was monitored for about 5 months prior to the commencement of the study. Conidial suspensions of the California isolates of B. bassiana and M. anisopliae s.l. were applied one week before, after, or at the time of applying microsclerotia of M. phaseolina to the potting mix. The following treatments were evaluated in the study:
- Untreated control
- Soil inoculated with M. phaseolina
- Soil inoculated with B. bassiana 1 week prior to M. phaseolina inoculation
- Soil inoculated with M. anisopliae s.l. 1 week prior to M. phaseolina inoculation
- Soil inoculated with B. bassiana at the time of M. phaseolina inoculation
- Soil inoculated with M. anisopliae s.l. at the time of M. phaseolina inoculation
- Soil inoculated with B. bassiana 1 week after to M. phaseolina inoculation
- Soil inoculated with M. anisopliae s.l. 1 week after to M. phaseolina inoculation
Entomopathogenic fungi were applied as 1X1010 viable conidia in 100 ml of 0.01% Dyne-Amic (surfactant) solution distributed around the plant base. To apply M. phaseolina, 5 grams of infested cornmeal-sand inoculum containing 2,500 CFU/gram was added to four 5 cm deep holes around the base of the plant. Each treatment had six pots each planted with a single strawberry plant representing a replication. Treatments were randomly arranged within each replication. The study was repeated once a few days after the initiation of the first experiment.
Plant health was monitored starting from the first week after the M. phaseolina inoculation and continued for seven weeks. Plant health was rated on a scale of 0 to 5 where 0=dead and 5=very healthy and the rest of the ratings in between depending on the extent of wilting. Data from both experiments were combined and analyzed by ANOVA using Statistix software and significant means were separated using LSD test. The influence of entomopathogenic fungal treatments applied at different times as well as the combined effect of different applications within each fungus were compared for seven weeks. Ratings for some plants that were scorched from hot summer temperatures and died abruptly were removed from the analyses.
Untreated control plants maintained good health throughout the observation period varying between the rating of 4.3 and 4.9. In general, plant health declined considerably from the 5th week after M. phaseolina inoculation. Plant health appeared to be slightly better in plants treated with entomopathogenic fungi, but there was no statistically significant difference in any except one instance. Plants treated with M. anisopliae one week prior to the application of M. phaseolina had a rating of 3.0 compared to 1.6 rating of plants inoculated with M. phaseolina alone.
When data from different treatments for each entomopathogenic fungus were compared, both B. bassiana and M. anisopliae s.l. appeared to reduce the wilting, but the plant health rating was not significantly different M. phaseolina treatment alone.
This is the first report of the impact of entomopathogenic fungi on M. phaseolina with some promise. Additional studies under more uniform environmental conditions and with more treatment options would shed more light on this approach of using entomopathogenic fungi against M. phaseolina. The current study evaluated single application of the entomopathogenic fungi and we plan to conduct additional studies with multiple applications.
Acknowledgements: We thank Dr. Kelly Ivors (previously at Cal Poly San Luis Obispo) for the pathogen inoculum and Dr. Stefan Jaronski, USDA-ARS, Sidney, MT for multiplying the entomopathogenic fungal inocula.
Dara, S. K. and D. Peck. 2017. Evaluating beneficial microbe-based products for their impact on strawberry plant growth, health, and fruit yield. UC ANR eJournal Strawberries and Vegetables. https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=25122
Dara, S. K. and D. Peck. 2018. Evaluation of additive, soil amendment, and biostimulant products in Santa Maria strawberry. CAPCA Adviser, 21(5): 44-50.
Dara, S. K., S.S.R. Dara, and S. S. Dara. 2017. Impact of entomopathogenic fungi on the growth, development, and health of cabbage growing under water stress. Amer. J. Plant Sci. 8: 1224-1233. http://file.scirp.org/pdf/AJPS_2017051714172937.pdf
Dara, S. K., S. S. Dara, S.S.R. Dara, and T. Anderson. 2016. First report of three entomopathogenic fungi offering protection against the plant pathogen, Fusarium oxysporum f.sp. vasinfectum. UC ANR eJournal Strawberries and Vegetables. https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=22199
Koike, S. T., G. T. Browne, and T. R. Gordon. 2013. UC IPM pest management guidelines: Strawberry diseases. UC ANR Publication 3468. http://ipm.ucanr.edu/PMG/r734101511.html
Partridge, D. 2003. Macrophomina phaseolina. PP728 Pathogen Profiles, Department of Plant Pathology, North Carolina State University. https://projects.ncsu.edu/cals/course/pp728/Macrophomina/macrophominia_phaseolinia.HTM
Vasebi, Y., N. Safaie, and A. Alizadeh. 2013. Biological control of soybean charcoal root rot disease using bacterial and fungal antagonists in vitro and greenhouse condition. J. Crop Prot. 2(2): 139-150.
Charcoal rot control with entomopathogenic fungi
1 week after Macrophomina inoculation
2 weeks after Macrophomina inoculation
3 weeks after Macrophomina inoculation
4 weeks after Macrophomina inoculation
5 weeks after Macrophomina inoculation
6 weeks after Macrophomina inoculation
7 weeks after Macrophomina inoculation
Data combined for each entomopathogenic fungus
The following is an article from a California Agriculture magazine published in the year 2000, and in using two case studies from California, is quite instructive on what it takes to successfully introduce mechanization and automation into a cropping system.
A few summary points about mechanization of harvest and the article linked below.
Success is found in integrated programs of research work: In 1950, a breeder and agricultural engineer at UC Davis worked hand in hand to develop a system for mechanized harvesting of processing tomatoes. The plant breeder developed a tomato that could withstand the stress of mechanical harvest, while the engineer came up with a machine that could successfully remove the tomato from the plant.
The gains are worth the effort: This mechanized harvester reduced the labor requirement per ton of tomatoes to 2.9 hours from 5.3 hours. A similar arc of reduction of labor took place in rice, where combinations of cultural practices, plant breeding and mechanization resulted in a reduction of 4.5 labor hours to harvest a ton of dry rice in the 1930's to 0.4 labor hours to harvest a ton of dry rice in the early eighties.
Success takes time: After 12 years of hard work on the part of the team from UC Davis, the mechanical harvester for processing tomatoes was commercially available. In rice, the large reduction in labor hours noted above took close to fifty years. Nevertheless, they happened.
So what does this all mean for us in the berry business? For one, waiting for Captain Marvelous to show up and build a machine in one go that picks fruit like a person in fields just like we are now growing them doesn't appear to have a precedent.
On the other hand, given the two case histories outlined above I am convinced that an integration of disciplines, a lot of hard work as an industry and the patience to support this endeavor through is what it will take to build the harvester we all want.
The article is very much worth the read, probably not more than 15 minutes of your time. Read it.
Mechanized harvest of tomatoes in California.
No, I don't think so and see for yourself with the photo series below. I have quite a few more of these pictures, but I think you'll get the point with the two series posted.
I've been getting a host of questions concerning what appears to be redberry mite on primocane blackberries - PrimeArk 45 and proprietary varieties - with red druplets mixed in with ripe ones, but if one marks the fruit and waits for a couple of days the red druplets have ripened fully. Now, the question is how this uneven maturity affects fruit quality, but that is something to be answered another day.
July 11, 2017 fruit 1.
July 13, 2017 fruit 1.
July 11, 2017. Fruit 2.
July 13, 2017. Fruit 2.
A recent page one article in a major American newspaper lamented the declining number of skilled botanists in the US. Something about animals being more interesting, with the net result that we are left with very few people who can distinguish between hydrangeas and rhododendrons, and speak intelligently about the difference in plants of thorns, spines and prickles (each arises from a different biological systems).
Well, lament no more my friends. Our Environmental Horticulture Farm Advisor, Steve Tjosvold, who is a botanist par excellence, has offered to share his 30+ years in the field with us on this subject and many others on his just launched nursery and flower grower blog.
Have a look:
I've had a request for the link to the article from a dear reader, it's right below. It seems that these Wall Street Journal links are not free, I apologize for that, but you have my commitment that I will explain clearly what the article is about in my posts.