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OMRI certification of the organic biopesticide Mycotrol-O

Mycotrol-O is a biopesticide with the entomopathogenic fungus Beauveria bassiana as the active ingredient.  Beauveria bassiana is pathogenic to a wide range of arthropod pests and I have used both Mycotrol-O and the conventional formulations BotaniGard 22WP and BotaniGard ES in several studies against multiple pests over years.  It showed good potential against thrips in lettuce, aphids in broccoli, lygus bug and spider mites on strawberries.  The combination of Mycotrol-O and azadirachtin emerged as a good tool for managing root aphids in organic celery and Mycotrol-O consistently performed better than other options against Bagrada bugs in my laboratory assays.

On 24 August, a grower who has been using Mycotrol-O for controlling Bagrada bug on multiple crops sent me an email he received from the distributor that the OMRI certification of Mycotrol-O will expire as of 28 August, 2015.  When I contacted Bioworks, Inc. that markets Mycotrol-O, they confirmed that one of the ingredients of the carrier was challenged by OMRI for organic production and their new formulation, Mycotrol ESO is waiting for registration.  LAM International Corp, the manufacturer of Mycotrol-O, notified on 31 August that OMRI accepted their appeal to review the status of the product.  This means, Mycotrol-O will remain in OMRI approved status until further notification.

Metarhizium brunneum (=M. anisopliae) and Isaria fumosorosea (=Paecilomyces fumosoroseus) are the other two entomopathogenic fungi that are commercially available, but only the latter is registered for organic use.  Beauveria bassiana is an effective pathogen and several growers are using against multiple pests.

Growers and PCAs can continue to use Mycotrol-O based on the current information.

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Posted on Wednesday, August 26, 2015 at 9:09 PM

Reporting the occurrence of rice root aphid and honeysuckle aphid and their management in organic celery

A few species of aphids infest celery in California.  According to the UC IPM Pest Management Guidelines, the black bean aphid (Aphis fabae), the foxglove aphid (Aulacorthum solani), the green peach aphid (Myzus persicae), the hawthorn or parsley aphid (Dysaphis apiifolia), and the cotton or melon aphid (Aphis gossypii) attack celery and cause varying levels of damage.  These aphids feed on the aboveground plant parts – leaflets and petioles – and some of them are vectors of virus diseases such as western celery mosaic, celery calico, cucumber mosaic, celery yellow spot and others.

Organic celery field in Santa Maria.  Aphid damage to the roots stunted the plant growth and reduced the plant stand.  Photo by Surendra Dara


Normal plant (above) and severely stunted plant (below) from aphid damage to the root system.  Photo by Surendra Dara


Aphids feeding on celery roots.  Photo by Surendra Dara

In late 2014, an organic celery field in Santa Maria was severely infested with aphids feeding on the root system.  Damage stunted plant growth and resulted in up to 80% of yield loss.   Gillian Watson at CDFA identified the aphid specimens as the rice root aphid, Rhopalosiphum rufiabdominale (Sasaki) and the honeysuckle aphid, Hyadaphis foeniculi (Passerini).  While there was only one earlier record of the honeysuckle aphid infestation on celery, according to the CDFA records, the rice root aphid has never been reported on celery.  This is the first record of the rice root aphid on celery.  Multiple species of the genus Hyadaphis are referred to as honeysuckle aphid, coriander aphid, and others in the literature, but the one identified on celery was H. foeniculi.

Adult rice root aphid. Photo by Brian Cabrera, Entomologist, Santa Barbara Ag Commissioner's Office

The rice root aphid is known to infest graminaceous (barley, rice, and wheat), rosaceous (apricot and plum), and solanaceous (potato and tomato) crops and is known to vector the barley yellow dwarf virus of grasses and small grains.  The honeysuckle aphid is known to be an important pest of apiaceous (fennel), caprofoliaceaeous (honeysuckles), and lamiaceous (mints) plants and involved in the transmission of 13 viruses.  

Depending on the host plant they are feeding on, the wingless form of the rice root aphid can be olive to dark green or brownish with yellowish tints or reddish or greenish-brown along with bluish-white wax on the body.  The wingless form of the honeysuckle aphid is greyish green or light green with dark appendages.

Field study methodology:

Natural enemies such as coccinellids, syrphid fly larvae, and lacewings play an important role in biological control of aphids infesting aboveground parts of the plant and root aphid management is a challenge especially in organic cropping systems.  To address the issue, a field study was conducted using the following treatments: i) untreated control, ii) Ecotec (rosemary oil 10% and peppermint oil 2%) 19.2 fl oz along with 12 fl oz of Kinetic (silicone and non-ionic surfactants), iii) AzaGuard (azadirachtin) 6.3 fl oz along with 20 fl oz of OroBoost (alcohol ethoxylate), iv) Mycotrol-O (Beauveria bassiana) 1.5 qrt, v) Mycotrol-O 1.5 qrt along with AzaGuard 6.3 fl oz, vi) Venerate (Burkholderia spp.) 2 gal, and vii) Grandevo (Chromobacterium subtsugae) 2 lb per acre.  Each treatment was about 0.3 acres of single plot and pesticides were administered through the drip system at 250 gpa rate for 40-45 min on December 9 and 23, 2014.  Aphid infestations were evaluated on December 6 (pre-treatment), December 22 (13 days after the first treatment), and January 2, 2015 (10 days after the second treatment).  On each sampling date, 10 plants were pulled out from random locations within each treatment, roots were washed in mild soap water, and aphids floating on the surface were filtered and counted.  Data were subjected to analysis of variance and significant means were separated using Tukey's HSD test.

Results:

There was a significant difference in aphid numbers among different treatments before and after each application (P < 0.002) and when the average for both applications (P < 0.0001) was considered.  When the overall change in aphid populations after both applications compared to the pre-treatment numbers was considered, there was a 3% reduction in untreated control, 24, 18, and 129% increase in Ecotec, AzaGuard, and Mycotrol-O treatments, respectively.  However, Mycotrol-O along with AzaGuard provided a 62% reduction in aphid populations followed by a 29% reduction by Grandevo and 24% by Venerate.  This study demonstrates the potential of non-chemical options in managing aphid populations in organic celery.  Microbial pesticides especially in combination with botanical pesticides can play a significant role in pest management.  Understanding the modes of actions of different options and using the right combinations is critical in pest management decisions.


Number of aphids (both species included) per plant before and after each pesticide application (above) and before and after both applications (below)

 Change in aphid populations before and after treatments.

Acknowledgements:

Thanks to the technical assistance of Cintia Perez and Emmy Williams and industry collaborators for donating the products. 

References

AphID. 2014.  Hyadaphis foeniculi. (http://aphid.aphidnet.org/Hyadaphis_foeniculi.php)

AphID. 2014. Rhopalosiphum rifiabdominale. (http://aphid.aphidnet.org/Rhopalosiphum_rufiabdominale.php)

Blackman, R. L. and V. F. Eastop.  2006.  Aphids on world's plants (http://www.aphidsonworldsplants.info/d_APHIDS_R.htm#Rhopalosiphum and http://www.aphidsonworldsplants.info/d_APHIDS_H.htm#Hyadaphis)

Halbert, S. E. 2003.  Coriander aphid, Hyadaphis coriandri(Das) (Insecta: Hemiptera: Aphididae).  University of Florida IFAS Extension publication EENY-296. (https://edis.ifas.ufl.edu/pdffiles/IN/IN57400.pdf)

Jedlinski, H. 1981.  Rice root aphid, Rhopalosiphum rufiabdominalis, a vector of barley yellow dwarf virus in Illinois, and the disease complex.  Plant Disease 65: 975-978. (https://www.apsnet.org/publications/plantdisease/backissues/Documents/1981Articles/PlantDisease65n12_975.pdf)

The Morton Arboretum.  2013. Honeysuckle aphid. (http://www.mortonarb.org/files/Honeysuckle%20aphid%20%28Feb%202014%29.pdf)

Posted on Friday, August 21, 2015 at 11:05 AM

Ken Tate is 2015 recipient of James H. Meyer Distinguished Achievement Award

The following appear in CA&ES Currents Newsletter, August 13, 2015. Congratulations Ken!!!

UC Cooperative Extension specialist Kenneth Tate is the 2015 recipient of the James H. Meyer Distinguished Achievement Award. The award recognizes a distinguished career of achievement by an Academic Federation member. A secondary but important consideration is voluntary service to the campus, UC community, or state, regional, or national bodies.

Tate has compiled an impressive record of collaborative and solution-oriented research addressing agricultural and environmental issues across California's 57 million acres of rangeland. He provides science and education leadership to California's diverse rangeland stakeholders and the campus community and has been repeatedly recognized for his work on surface water quality on rangelands. He has given more than 400 extension presentations, published more than 100 journal articles, served as principal investigator on 37 research and extension grants ($6.3 million), and as co-principal investigator on another 43 research and extension grants ($5.7 million).

Tate works with private landowners, agency land managers, and regulatory agency staff to understand the fate and transport of surface water pollutants. Early in his career he helped identify management practices to reduce drinking water contamination risks by livestock-borne Cryptosporidium parvum and other pathogens, which enabled ranching families to continue sustainable grazing practices on watersheds east of San Francisco. He has also worked with these groups to identify and implement realistic management practices to reduce pollutants. Tate is known for his ability to build consensus among diverse audiences on controversial topics related to range livestock production. In 2011, he developed the biennial UC Rustici Rangeland Science Symposium that features scientists, policymakers, and ranchers working on key rangeland issues.

“Dr. Tate has advanced a remarkable and productive research and extension career in range management and environmental stewardship,” said Department of Plant Sciences chair Chris van Kessel in nominating Tate for the award. “His program has been exemplary in bringing together diverse research and management collaborations to evaluate scientific information relevant to targeted issues, contribute new scientific knowledge, and extend tools and knowledge to serve the needs of society."

Posted on Thursday, August 13, 2015 at 3:22 PM

Efficacy of botanical, chemical, and microbial pesticides on twospotted spider mites and their impact on predatory mites

Twospotted spider mite, Tetranychus urticae Koch is a major pest of strawberries in California.  Spider mite damage reduces plant vigor and contributes to yield loss.  Twospotted spider mites are typically found on the lower side of the leaf and form webbing at higher population levels. 

Damage: Spider mites cause damage by puncturing the epidermis with their mouthparts and sucking the plant juices.  Death of plant cells appears as yellow mottling during initial stages and as feeding continues, damaged areas coalesce and result in scarring, bronzing, and drying out of leaf tissue.  This reduces the photosynthetic ability of the plant and thus its growth and vigor.  If left uncontrolled, damage leads to stunted plant growth or eventual death.  Damage symptoms are unique in Benicia variety where upper leaf surface corresponding to spider mite feeding on the lower side, shows purplish coloration.


Yellowing, scarring, bronzing, and drying of infested foliage and stunting of plants.  (Photo by Surendra Dara)

Biology: Life cycle includes egg, larva, protonymph, deutonymph, and adult stages.  Females lay an average of 100 eggs in 10 days.  Eggs are round, initially translucent and turn whitish as they mature.  Larvae have three pairs of legs and nymphal stages have four pairs of legs.  Males are wedge-shaped and about 0.3 mm long.  Females are oval, 0.4-0.5 long, and have a single dark spot on either side of their body.  At 85-90 oF, life cycle can be completed in 7-8 days.


Life stages of twospotted spider mite (Photo by Surendra Dara)

Management: Growers typically rely on biological and chemical control options for managing twospotted spider mites in strawberries. Type I specialist Phytoseiulus persimilis Athias-Henriot, Type II specialists Neoseiulus fallacis (Garmin), N. californicus (McGregor), Galendromus occidentalis (Nesbitt), and Type III generalist Amblyseius andersoni (Chant) are common predatory mites that attack twospotted spider mites.  Releasing one or more species of predatory mites is a popular practice in strawberry production.  Abamectin, acequinocyl, bifenazate, etoxazole, fenbutatin-oxide, fenpyroximate, hexythiazox, and spiromesifen are the most commonly used chemical miticides according to pesticide use reports of the California Department of Pesticide Regulation.    Chemical miticide use shows a 2% increase in the Watsonville-Salinas area, an 82% increase in the Santa Maria area, and a 125% increase in the Oxnard areas from 2009 to 2013.  There is a continued need for identifying effective chemical and non-chemical miticides to manage twospotted spider mite in strawberries.

            A small plot field study was conducted in 2013 at Manzanita Berry Farms in Santa Maria to evaluate the efficacy of various botanical, chemical, and microbial pesticides.  Treatments included bifenazate  (Acramite 50 WS at 1 lb/ac), abamectin (Agri-Mek SC at 4.29 fl oz/ac), entomopathogenic fungus Beauveria bassiana (BotaniGard ES at a lower label rate of 1 qrt/ac) + bifenazate (Acramite 50 WS at the lowest label rate of 0.75 lb/ac), rosemary and cotton seed oil (Eco-Mite at 1% concentration), fenpyroximate (Fujimite 5 EC at 2 pt/ac), fenpyroximate (Fujimite XLO at 2 pt/ac), Chromobacterium subtsugae strain PRAA4-1 (Grandevo at 2 lb/ac), Burkholderia sp. strain A396 (Venerate XC at 2 gal/ac), and cyflumetofen (Nealta SC at 13.7 fl oz/ac).  A spray volume of 150 gal/acre was used with 0.25% non-ionic surfactant except for the treatment with B. bassiana, where an organo-silicon surfactant was used.  Each treatment had a 15' long strawberry bed and treatments were replicated in randomized complete block design.  Treatments were applied using a CO2 pressurized backpack sprayer twice at weekly intervals and eggs and mobile stages of twospotted spider mites and predatory mites were sampled 3 and 7 days after each application.  On each sampling date, 10 mid-tier leaflets were collected from 10 random plants within each plot and mites were collected using a mite brushing machine and counted under microscope.  Data were analyzed using analysis of variance and significant means were separated using Tukey's HSD test.

            Pre-treatment counts were not available due to a technical issue, so comparisons were made for pest and predatory mite counts after each spray application and the post-treatment period as a whole.  Compared to untreated control, treated plots had fewer spider mites throughout the observation period, but the pest suppression was not statistically significant (P > 0.05, Table 1).  When the percent reduction in treatments relative to untreated control was compared, rosemary+cotton seed oil, fenpyroximate EC, and B. bassiana+bifenzate had relatively higher reduction in mobile stages while Burkholderia sp., rosemary+cotton seed oil, and cyflumetofen had a higher reduction in eggs after the first spray application (Fig. 1A).  Reduction in mobile stages following the second spray was the highest in cyflumetofen followed by bifenzate, rosemary+cotton seed oil, fenpyroximate XLO, and EC (Fig. 1B).  After the second spray, the highest reduction in eggs was seen in fenpyroximate EC followed by Burkholderia sp., cyflumetofen, rosemary+cotton seed oil, and B. bassiana+bifenzate.  In general, rosemary+cotton seed oil treatment did a better job of reducing egg and mobile stages after both applications followed by Burkholderia sp., cyflumetofen, and fenpyroximate EC (Fig. 1C).


Table 1. Number of eggs or mobile stages (mean+SE) of twospotted spider mite 3 and 7 days after first and second spray treatment along with post-treatment average.

Fig. 1. Percent reduction in eggs and mobile stages of twospotted spider mites in different treatments compared to untreated control after first (A), second (B), and both spray applications (C).

            There were no statistically significant differences in predatory mite populations among treatments except in mobile numbers on 7 days after the first spray (P = 0.0046, Table 2).  Plots that were treated with Burkholderia sp. and cyflumetofen had a relatively higher number of predatory mites and bifenzate and abamectin had lower numbers, in general.

Table 2. Number of eggs or mobile stages (mean+SE) of predatory mites 3 and 7 days after first and second spray treatment along with post-treatment average.

            Although treatment differences were not statistically significant, this study demonstrates the efficacy of various botanical, chemical, and microbial pesticides against twospotted spider mites and their safety to predatory mites.  Results show the potential of non-chemical alternatives, which can be used in rotation with chemical pesticides for a sound IPM program.

General IPM recommendations:

  • Obtain transplants from a clean source to avoid early spider mite infestations, which could lead to season long problems in production fields.
  • Periodically scout the fields to evaluate infestation levels and make appropriate management decisions.
  • Rotate chemicals among different modes of action groups and consider botanical and microbial control options to reduce the risk of resistance development.
  • Understand the dietary preferences and environmental requirements of different species of predatory mites and release the right species appropriate for the situation.
  • Avoid water stress for plants as spider mites thrive when plants are under stress.
  • Excessive nitrogen fertilization encourages spider mite population build up, so optimize fertilizer input.

Acknowledgments: Thanks to Dave Peck, Manzanita Berry Farms, Santa Maria for his collaboration, pesticide industry partners for the financial support, and Sumanth and Suchitra Dara for their technical assistance with mite brushing.

References

Blecker, S.  2015.  Pesticide use trends in strawberries.  Presentation at Santa Maria Strawberry Field Day. http://cesantabarbara.ucanr.edu/files/213517.pdf

Dara, S. K. 2014.  Managing spider mites in California strawberries.  UCCE eNewsletter Strawberries and Vegetables.  http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=13943

Dara, S. K. 2014.  Predatory mites for managing spider mites on strawberries.  UCCE eNewsletter Strawberries and Vegetables.  http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=14065

Hoffland, E., M. Dicke, W. V. Tintelen, H. Dijkman, and M.L.V. Beusichem.  2000.  Nitrogen availability and defense of tomato against two-spotted spider mite.  J. Chemical Ecol. 26: 2697-2711.

 

Posted on Tuesday, August 4, 2015 at 11:42 AM

Calculate Your VOC Emissions

As summer continues to heat up, keep in mind that regulations remain in effect to reduce the volatile organic compounds (VOCs) that can be emitted into the atmosphere by pesticides and other harmful chemicals and contribute to the amount of ozone or smog in the environment.  

Calculators from the Department of Pesticide Regulation (DPR) that determine the VOC emissions from fumigant and non-fumigant pesticides before application are available to help growers, pest control advisers, and pesticide applicators comply with the regulations.  The UC Statewide Integrated Pest Management (IPM) Program provides a link to these calculators from each of the treatment tables in the UC Pest Management Guidelines.  Click on the Air Quality – Calculate emissions button.

Take steps to reduce VOCs.  Avoid emulsifiable concentrate (EC) formulations as they release the highest VOC emissions.  Pesticide control advisers and growers can also reduce VOC emissions by employing IPM practices such as using resistant varieties, traps, exclusion, and biological control.  When using pesticides, spot-treat and seek low-emission materials.  Solid formulations, such as granules or powders, are best.

Check the fact sheet on the DPR web site for the most up-to-date-information on VOC restrictions and regulations.

Posted on Wednesday, July 22, 2015 at 7:39 AM

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