Ruthann Anderson, Editor
2017 Renewal Information for DPR License and Certificate Holders
Renewal Time is Here for M-Z Licensees!
DEPARTMENT OF PESTICIDE REGULATION LICENSING AND CERTIFICATION
SUBMIT APPLICATIONS BEFORE NOVEMBER 1 Mail your application before November so that your license or certificate can be issued before it expires. If you submit before October, you will be renewed by early December and can then register with your county before the New Year. .
Blah blah blah blah
Blah blah blah bl
AVOID PROCESSING DELAYS
Submitting earlier allows DPR staff additional time to notify you of issues or problems that could delay processing your license.
M-Z LICENSEES
DPR will mail renewal packets in August to license and certificate holders with surnames and business names starting with letters M-Z
PEST CONTROL BUSINESSES Renew your qualified applicator FIRST. For pest control businesses, the qualified applicator MUST BE renewed before the business license can be renewed. If you do not receive your application contact the Licensing Program at licensemail@cdpr.ca.gov or download a blank application at: www.cdpr.ca.gov/docs/license/lictypes.htm
Dates for Renewal DPR encourages submitting your completed renewal application by November 1st, 2017 to receive your license/certificate by December 31st, 2017. If submitted after November 1st, you may not receive your license/certificate by January 1st. Processing time can take up to 60-working days. Note that submitting your renewal before October will ensure you have your license by early December and allow you to renew with the county by the New Year. Questions about your CE hours? For questions about your CE hours, you must contact the course sponsor or your professional
association. See DPR’s website for current or previous years’ courses and sponsors’ contact info: http:// www.cdpr.ca.gov/docs/license/cont_ ed_cfm/classes.htm Mailing of Renewal Packets DPR mailed renewal packets in August to provide sufficient time for license and certificate holders to submit their applications by November 1st. Renewal applications must be postmarked on or before December 31st, or a late fee applies. If you did not receive your renewal application or lost it, download a renewal packet from DPR’s website: www.cdpr.ca.gov/docs/license/liccert. htm or email DPR at LicenseMail@ cdpr.ca.gov to request a copy.
APPLICATOR ALERTS IN THIS ✔ CAPC
ISSUE:
the Edito A ED Up
grand sierra resort Reno, Nevada
r - p. 1
date - p. 2 ✔ Herbic ide Applic ation Equ ipment - p ✔ Dyer’s .3 Woad ID & Manage ment - p. 4 ✔ Herbic ide Resis tance in R ice - p. 6 ✔ Boots on the G round - p .8 ✔ Weed Control in Spinac h - p. 9 ✔ Prome tryn in C ilantro p. 10
15 CEUs CDPR
CAPCA.COM/CONFERENCE Registration Rates: Rates increase after 9/15/17
Accommodations:
Member/Exhibitor - $300 Non Member - $370 Student - $150 Spouse - $150 Children - $100 Golf Fees - $95 Clay Shoot - $75
GSR Standard Room - $105 Summit Suites - $125
Luncheon Performance:
SEPTEMBER 2017 VOL. 1I, NO. 3
✔ From
october 15-17, 2017
APPLICATOR ALERTS
From the Editor
CAPCA EDITORIAL STAFF
Ruthann Anderson - Editor
Joyce Basan - Deputy Editor Dee Strowbridge - Membership/Conference Sylvia Stark - Advertising Sales Manager Lien Banh - Office Manager Ariana Zamora - So. CA Representative Jacqueline Tabarez - No. CA Representative Rachel Taft - Executive Assistant Adam Barsanti - Outreach Relations Manager Graphic Design - Rosemary N. Southward southwardr@comcast.net PURPOSE California Association of Pest Control Advisers (CAPCA) is a non-profit voluntary mutual benefit association. CAPCA’s purpose is to serve as the leader in the evolution of the pest management industry through the communication of reliable information. CAPCA is dedicated to the professional development and enhancement of our members’ education and stewardship which includes legislative, regulatory, continuing education and public outreach activities. PUBLISHING INFORMATION Applicator Alerts is published by the California Association of Pest Control Advisers (CAPCA), 2300 River Plaza Dr., Suite 120, Sacramento, California 95833. Web: www.capca.com, (916) 928‑1625. POSTMASTER: send address change to CAPCA. CAPCA has endeavored to include appropriate and accurate statements, but disclaims any and all warranties and/or responsibility for the statements or articles submitted to Applicator Alerts that may have additionally been edited for style, content and space prior to publication. Views expressed are those of the authors and do not necessarily represent CAPCA policies, or positions or endorsements. Editorial content of this publication is educational and informational in nature. No part of this publication, including images, may be reproduced without prior written permission from the publisher. Contact CAPCA at (916) 928‑1625 for reprint authorization. PRINTING: Sundance Press Tucson, Arizona
FIND US ON LINKEDIN: https://www.linkedin.com/company/californiaassociation-of-pest-control-advisers-capca-
Quick knock down of fungal and bacterial pathogens including: Alternaria, Anthracnose, Botrytis, Bacterial Leaf Spot and Blight, Bacterial Canker, Downy and Powdery Mildew
t
Kills spores on contact
t
No pathogen resistance
t
Tank mix with conventionals
t
No preharvest interval
BEE FRIENDLY
Contact Jay Sughroue, PhD 951.719.9244 | biosafesystems.com
CAPCA Ed – 2017 Schedule Mark your calendars now for these valuable training events. September 12, 2017 / San Jose / CAPCA Ed September 13, 2017 / Santa Paula / CAPCA Ed September 14, 2017 / Bakersfield / CAPCA Ed September 21, 2017 / Modesto / CAPCA Ed September 27, 2017 / Chico / CAPCA Ed October 15- 17, 2017 / Reno, NV / CAPCA Conference November 1, 2017 / Sacramento / CAPCA Ed November 9, 2017 / Tulare / CAPCA Ed November 14, 2017 / Napa / CAPCA Ed November 15, 2017 / Modesto / CCA November 15, 2017 / Arcadia / CAPCA Ed November 16, 2017 / Santa Ana / CAPCA Ed November 29, 2017 / Bakersfield / Nutrient Management November 30, 2017 / Gilroy / Nutrient Management Watch our website for registration information: https://capcaed.com/ For additional information contact: Ariana Zamora, So. CA CAPCA ED Representative ariana@capca.com / (805) 704-3255 Jackie Tabarez, No. CA CAPCA ED Representative jackie@capca.com / (916) 928-1625 x205
Cheryl Wilen, Area IPM Advisor, UC Statewide IPM Program THERE HAS BEEN a lot of interest recently in reducing glyphosate use by cities, municipalities, and around schools. This has spilled over into the residents’ desire to reduce the use of all synthetic herbicides. Many applicators are able to switch to alternative products such as those with plant oils or acetic acid as the active ingredient. Use of mechanical methods such as mowing or blade or sting trimmers has also increased. However, there are still some situations where the use of a synthetic herbicide can be the appropriate control measure. Examples include management of perennial invasive species, removal of poisonous plants such as poison oak, and areas where it is dangerous for road crews to be close to roads. Applicators can reduce the overall amount of synthetic herbicides used by making some changes in how the products are applied. For example, I recently did a “spray and pray” test just to see how a wick applicator and
a spinning disc sprayer for controlled droplet application (CDA) would compare to a backpack sprayer with a flat fan nozzle. The figure below shows the results of treating barley with the same concentration (3%) of glyphosate 1 week after application. Although it is difficult to see from the photo, the areas treated were the same size. The backpack application had excellent control but used about 16 oz of spray solution which would be about 1/2 oz or 15 ml of herbicide. The controlled droplet application also provided excellent control and only used about 2 oz of spray solution. This means that only 2ml of herbicide was applied – a large reduction. However, you can see that there is a section in the middle where the barley is still green. This is from operator error. The mist is so fine that even with an indicator dye added it was hard to see where I was spraying. The other problem with the model I was using was that
the herbicide is dispensed by gravity into a cup at the head where spinning disks spray out the solution. Unless the sprayer was kept upright all the time, the solution would spill out. While this was not a problem while spraying, when I was done I could not set the sprayer down or drain it back into the tank without spilling it. Another drawback is that it may be difficult to apply to small (less than 1 ft) spray swaths. Finally, the wick treatment did not affect the barley at all. Even though the wick was fully saturated and I passed over the plants numerous times, it did not appear that the herbicide was getting on the plants. The other problem with the wick is that it is like a paint roller and holds a large quantity of herbicide solution. The only way to clean it was to put it in a bucket and try to squeeze it off, followed by washing off in the bucket. As you know, the rinsate is considered hazardous waste but can be applied to a site as described on the label. There was a lot of rinsate so the time spent cleaning the wick and then using a sprayer to dispose of the remaining material was too timeconsuming to justify the use of this system. My conclusion is that the CDA system can be a good way to reduce overall herbicide use without compromising weed control but there are some application kinks that need some work. The wick system I tested is not a good choice due to lack of control as well as difficulty in cleanup. The backpack is reliable but uses the most herbicide. While not covered here, there are modifications one can make to backpack sprayers by changing out nozzles and using pressure regulators that can make them more accurate in calibration. 3
WEED MANAGEMENT
Overview of Various Herbicide Application Equipment for Reducing Overall Usage
WEED MANAGEMENT
Dyer’s Woad Identification and Management in California James J. Stapleton, UC IPM, Kearney Ag Center; and Steve B. Orloff, UCCE, Siskiyou County DYER’S WOAD (Isatis tinctoria) is a problematic, invasive weed in the intermountain west, including far northern California. Although the plant (locally known in Siskiyou County as ‘Marlahan mustard’) can be controlled by properly-timed herbicide applications prior to seed set, it continues to spread rapidly along roadsides, fencerows, and ditchbanks, as well as in natural areas and some cropland. The epicenter of the dyer’s woad infestation in California is the Scott Valley of Siskiyou County, where it was introduced in the 1800s. Until a decade or two ago, it was primarily confined to Scott Valley but spilled over into Shasta Valley and continues to spread throughout Siskiyou County and into Modoc, Shasta, and other northern California counties (CDFA, 2014). Although dyer’s woad has a long history of cultivation for its blue dye (think of the blue facepaint in the movie Braveheart) and still is grown commercially in some parts of the world, it has demonstrated its ability to invasively and aggressively colonize extensive areas of California, Oregon, Idaho, Utah, Wyoming and Montana. Dyer’s woad is a ‘B’ listed noxious weed in California. A new, UC IPM Pest Note on dyer’s woad, including nine diagnostic photographs, is now available online: http:// ipm.ucanr.edu/PMG/ PESTNOTES/pn74175. html (Stapleton & Orloff, 2017). Identification. Dyer’s woad is a member of the mustard family, and is typically one to four feet in height. The leaves have a prominent whitish nerve on the upper side of the leaf blade which makes it easy to identify. Dyer’s woad has typically mustard-like, small yellow flowers which appear during May and June, and their showy appearance 4
across the landscape can give a good indication of the extent of local infestations. Dyer’s woad seeds are distinctive, in that single seeds are borne within ½ to ¾-inch long seedpods (silicles) which are green at first, but gradually turn purplish brown or black at full maturity. The silicles provide protection to the seeds within, and seed longevity has been estimated to be eight years or longer. Dyer’s woad can be found in a wide range of microhabitats. It tends to first establish in disturbed areas, especially in light sandy and gravelly soils. It is primarily a weed of rangeland, woodlands and noncrop sites, but can also infest grain and alfalfa fields. Its spread can be facilitated by contamination of hay bales, grain lots, and machinery. Management. Like other mustards, dyer’s woad can be difficult to control because of its vegetative, rosette growth stage and deep root system. The most effective control measure for dyer’s woad is prevention, including careful monitoring and sanitation measures (Stapleton, 2012). In established infestations, do not let plants go to seed. Germination assays during 2013-14 showed that a portion of seeds became germinable while still green in color, so effective herbicide or mechanical control measures cannot be delayed in the springtime (Stapleton et al., 2014). Hand rogueing or digging individual plants is somewhat effective for small or scattered infestations. However, it may be necessary to remove plants in an infested area periodically for multiple years. Chemical control at appropriate growth stages is effective. The most effective herbicides for dyer’s woad control are 2,4-D and chlorsulfuron. Chlorsulfuron is generally more effective than 2,4-D, with both post- and pre-emergence activity. It is authorized for professional use only. A combination of 2,4-D with
chlorsulfuron is also highly effective. Glyphosate does control dyer’s woad but is usually not the herbicide of choice for broadcast applications because it is non-selective and will kill desirable vegetation. Spring treatment seems to be more effective than fall treatment in California, perhaps because plants are stressed in the fall due to a lack of soil moisture (Orloff, 2008). Multiple years of chemical control are needed to deplete the soil seedbank. See the UC IPM Pest Note for more information on chemical control. The key objective of any dyer’s woad control program is to prevent viable seed production and dissemination. Additional Resources: CDFA. 2014. Dyer’s Woad (Isatis tinctoria). Online: https://www.cdfa. ca.gov/plant/ipc/encycloweedia/ weedinfo/isatis.htm Orloff, S. B. 2008. Dyer’s woad (Marlahan mustard): control it now before it sets seed. Online: http:// cesiskiyou.ucanr.edu/newsletters/ Spring_200839564.pdf Stapleton, J.J., and Orloff, S.B. 2017. Pest Note: Dyer’s Woad. ANR Publication #74175, Davis, CA. 4 p. Online: http://ipm.ucanr.edu/PMG/ PESTNOTES/pn74175.html Stapleton, J.J. 2012. Vigilance, sanitation, and spot treatment can help prevent spread of invasive weeds. CAPCA Adviser Magazine, June 2012, pages 20-22. Stapleton, J.J., Orloff, S.B., and Luiz, N.O. 2014. High temperature and moisture effects on the germination of dyer’s woad seeds. In: Proceedings of the Western Society of Weed Science 67:6. Online: http://www. wsweedscience.org/wp-content/ uploads/2013/09/2014WSWS_ Proceedings_Final.pdf
NUTRITION CROP PROTECTION ADJUVANTS
The Leader In Sustainable Crop Inputs Recognizing the need for sustainable farming inputs, BRANDT introduced its first bio-pesticide over 30 years ago. Today, the company offers one of the largest portfolios of organically compliant crop inputs available and it continues to grow. BRANDT’S NEW OMRI LISTED PRODUCTS INCLUDE: BRANDT® EcoTec® Plus ■ Broad spectrum insecticide/miticide with ZERO REI/PHI BRANDT® Antixx® Plus Baits and kills ants and crawling insects ■ 1 lb of easy to apply granules treats 2,000 square feet ■
BRANDT® Organics Defoamer High quality, organically compliant formulation prevents and eliminates foam in the spray tank
■
To learn more, talk to your local Ag Retailer or PCA about BRANDT sustainable crop inputs or contact us at 559 499 2100 or info@brandt.co
Brandt Consolidated Inc. www.brandt.co
WEED MANAGEMENT
Planning an Herbicide Program in Rice: Dealing with Herbicide Resistance Whitney Brim-DeForest, University of California Cooperative Extension Rice Advisor OVER THE PAST 20 years, herbicide resistant weeds have become an everincreasing problem for California rice growers. The first resistant weeds were found back in the early 1990s, when smallflower umbrella sedge was found to be resistant to bensulfuron. Over the years, we have added several more species and chemicals, until the list has become increasingly long, making it more and more difficult to plan an herbicide program (Table 1). This is especially true when growers have more than one weed species with herbicide resistance. To make matters more complicated, on top of the high number of herbicide resistant weeds, rice growers have only a few modes of action available to them for each weed species. For a Pest Control Adviser, this can make it nearly impossible to plan a program that provides good weed control without being prohibitively expensive.
So what are the considerations one must take into account when planning a program for a grower with herbicide resistant weeds? 1) Weed species to be controlled: Not all fields have the same weed species present. Some may have one species that predominates a field. Tailoring the herbicide program to fit the field makes it most effective. 2) Which herbicides control which species? Pay careful attention to herbicide labels. The label gives information on whether a species is controlled or just suppressed. The University of California has an Herbicide Susceptibility Chart for rice, which has all of the most updated information summarized by species and herbicide. It can be found at http://rice.ucanr.edu/ files/229946.pdf.
Table 1. Herbicide resistance status of major California rice weeds, by modes of action. Registered Herbicides
Modes of Action
Early watergrass
8
6
Late watergrass
8
6
Barnyardgrass
8
6
Sprangletop
5
4
Smallflower umbrella sedge
10
5
Ricefield bulrush
10
6
Species
6
Herbicide Resistance Recorded 4 Modes of Action (multiple-resistance) 4 Modes of Action (multiple-resistance) 2 Modes of Action (multiple-resistance) 2 Modes of Action (no multiple resistance) 2 Modes of Action (multiple-resistance) 2 Modes of Action (multiple-resistance)
3) Herbicide resistance status of weeds: If you are unsure if you are seeing herbicide resistance in a field, or if the lack of control was caused by something else, get the weeds checked. The Rice Research Board funds the UC Weed Science program to provide free testing for all California rice growers and PCAs. More information on how to submit samples as well as seed collection best practices are available on the rice.ucanr.edu website. 4) How the herbicides will be applied: If a grower doesn’t have a ground-rig available, then it may be difficult to apply some liquid herbicides. Specifically, those herbicides that have aerial application restrictions may need to be replaced by other herbicides. 5) Method of planting: Does the grower drill-seed? Is drill-seeding an option? If not, the number of modes of action available for certain resistant weed species may be limited (grasses). For example, the use of pendimethalin is limited to drill-seeded systems. Fields with multiple-herbicide resistant watergrass may have no other modes of action available. If a grower cannot drill-seed, using a stale seedbed with glyphosate or another non-selective herbicide may be the best option. 6) Irrigation method and waterholding capacity of soil: If a field is going to be drained several times over a season, certain herbicides, especially those with long waterholding periods, cannot be used. Furthermore, some herbicides require soils with good waterholding capacity in order to work
7) Herbicides used in previous seasons: The best way to prevent resistance, and to prevent adding an additional mode of action to an already-resistant species, is to rotate herbicide modes of action. This is true both within- and between- seasons. Refer to the Herbicide Susceptibility Chart to ensure that herbicides are not the same mode of action.
An herbicide program template might look like this example: Weeds
Herbicide Options
Watergrass
clomazone, penoxsulam, bispyribac thiobencarb, propanil, cyhalofop, pendimethalin, orthosulfamuron
To make the process easy on your clientele, it is best to discuss these points before the season begins. Get clarity on water management, seeding method, and preferred herbicide application method. Scan this code with your mobile device to find UC’s Herbicide Susceptibility Chart for rice.
Herbicides Resistant
Water Management
Previous Season Herbicides
OPTIONS FOR CURRENT YEAR
clomazone, thiobencarb, penoxsulam
Continuous Flood
clomazone, cyhalofop
propanil, orthosulfamuron, bispyribac -or, switch to drill-seeded, use pendimethalin -or, use stale seedbed with glyphosate
ARBORJET EQUIPMENT & TREE-ÄGE® G4 FORMULATION WORK TOGETHER TO PROVIDE
TWO YEAR CONTROL OF POLYPHAGOUS SHOT HOLE BORER TREE-ÄGE G4 NOW AVAILABLE IN CALIFORNIA
Dawn Fluharty, Northwestern Regional Technical Manager 650-996-8291 • dfluharty@arborjet.com • PCA #126831 7
WEED MANAGEMENT
at all. If a field tends to drain easily, or the grower has difficulty keeping water on the field, herbicide performance may be affected. Some foliar-applied herbicides may require drainage periods for application, so planning the timing of the drains to maximize efficacy is important.
WEED MANAGEMENT
Boots on the Ground Q & A:
Right-of-Way and Non-Crop Weed Management Scott A. Johnson,Vegetation Management Specialist, Wilbur-Ellis Company APPLICATOR ALERTS (AA): What are some of the key factors for applicators to remember when dealing with unique application settings and situations when rightsof-way pass near or through surface waters, school grounds, Ground Water Protection areas, or other sensitive areas? SCOTT JOHNSON (SJ): There are many factors that will vary with each site, but priority should be placed on possible impacts to people, wildlife, and the environment. It is important to balance your vegetation management objectives with possible unwanted off-target consequences of any treatment. As one colleague once told me, “Non-crop is all-crop!” These days, that also includes urban and wildland sites. Remember – right-of-way sites are usually more visible (and accessible) to the public than agricultural crop settings. (AA): What basic precautions should applicators always take with herbicide use in these problematic situations? (SJ): Obviously, follow all label restrictions and precautions, as well as pertinent laws and regulations. Plan for and create possible buffers relative to the effects of weather, slope, soil texture. A little common sense can keep these situations from being problematic. Be prepared to explain to a passer-by – in plain English – what you are doing, how you are doing it, and why you are doing it. (AA): Who should an applicator consult about any special local regulations before applying an herbicide in these sensitive areas? (SJ): Get to personally know the Ag Commissioner Pesticide Use Enforcement staff in the county where you are working. It is better to ask “what-if” questions in a compliance mode than having to deal with them in an enforcement mode. This is especially true for applications in politically sensitive areas, or for first-time use of a chemical or application technique. They will appreciate the heads-up in case concerned citizens call with questions or complaints.
8
(AA): Can you cover briefly the advantages that IPM methods play in rights-of-way weed management? (SJ): IVM — Integrated Vegetation Management — is the “weed” component of IPM. Just as traditional IPM is with ag crops, IVM is a decision-making process that includes physical, cultural, and biological VM techniques in combination with herbicides. Sometimes a prescribed fire is the best way to clear a site, followed by herbicides to control resprouting plants, with livestock grazing as a maintenance strategy. There are many combinations and variations possible to apply this philosophy. (AA): What is one of the biggest herbicide-resistance challenges today in rights-of-way? (SJ): In my experience, solely relying on a single herbicide mode of action is herbicide resistance waiting to happen. I always tank mix with at least two modes of action, but more likely three or four in fall pre-emergent application. The labor cost of retreatment of missed weeds is many times higher than doing it right the first time. (AA): What are some points to always keep in mind when addressing herbicide efficacy? (SJ): I think of IVM as an ART. You can make your herbicide work better and achieve your VM objective if you: Use the right APPLICATION (spray technique), at the right RATE, at the right TIME (e.g., stage of weed growth, weather, etc). (AA): What would be your top three BMPs when it comes to rights-of-way and weed management? (SJ): 1. Manage to your client’s VM objectives, per the responses above. 2. Be prepared to explain these objectives to the client and the public. 3. Communicate, Communicate, Communicate – with everyone!
Richard Smith, Vegetable Crop and Weed Science Farm Advisor SPINACH PRODUCTION has significantly changed in the last 15 years. Spinach was commonly grown on 40-inch wide beds with two seedlines, but it is now grown on 80-inch wide beds planted with 18 to 42 seedlines on the bed top, using 1.5 to over 3.5 million seed per acre. On the densely planted bed top there is no opportunity to control weeds with cultivation. Weed control is therefore dependent on the impact of prior rotations on weed populations, effective use of cultural practices and the use of herbicides. Hand weeding is also used to control weeds, but hand weeding costs can be expensive and can be a make or break factor affecting profitability of the crop. In the recent UC publication, Sample costs to produce and harvest organic spinach (Tourte et al, 2015 http://coststudies.ucdavis. edu/current/ ), average hand weeding costs were documented at $440 per acre. However, weeding costs can fluctuate significantly depending on weed pressure and can easily exceed $1,000 per acre in weedy fields. There are two preemergent herbicides available for use in spinach production: cycloate and S-metolachlor. Neither of these materials have post emergence activity on weeds and are applied prior to planting or immediately post planting. Cycloate controls a wide spectrum of broadleaf weeds including purslane, hairy nightshade, lambsquarters, groundsel and sow thistle. It can
be applied up to 5.3 pints/acre, but lower rates are used on coarsetextured soils. It is volatile and must be incorporated into the soil to avoid loss. Following application, it is mechanically incorporated prior to planting or applied post planting and incorporated with the germination water. There is a 48 hour reentry interval which complicates incorporation of the material with the germination water; however, growers have figured out various methods of coping with this regulation by simply waiting to start the water for 48 hours or having the sprinkler pipe already set up and tested so that the water can be started from the edge of the field. We evaluated the level of weed control provided by cycloate if left on the soil surface for various amounts of time. Not surprising, weed control declines the longer it remains on the soil surface, but in a study conducted this year under cool temperatures in the spring, the level of weed control was still reasonably good after leaving the material on the surface for 48 hours before incorporation with irrigation. However, given the volatility of cycloate, it would be expected that there would be greater loss of the material as it remains on the soil surface during warmer temperatures. Cycloate has a short half-life in the soil and there are no plant back restrictions listed on the label. S-metolachlor also controls a wide spectrum of grass and broadleaf weeds including purslane, black
and hairy nightshades and burning nettle. It is applied at 0.33 to 1.0 pints/A post planting and preemergence to the weeds. Lower rates are used on coarse-textured soils. The label states that it is not recommended to mechanically incorporate the material in order to avoid crop injury; therefore, it is incorporated into the soil with the germination water. S-metolachlor has a 50 day preharvest interval (PHI) which is an issue because clipped spinach (the predominant type of spinach that is grown) matures in 25 to 35 days during the bulk of the cropping season. In order to comply with the PHI, it is necessary to make applications 14 days or more prior to planting spinach. In this scenario, applications are typically made to shaped beds and the material is incorporated with sprinkler irrigation two weeks prior to planting spinach. Applying an irrigation prior to planting tends to pack the bed down which is not desirable for effective stand establishment. However, growers have figured out various strategies for softening up the beds for planting without disturbing the treated area too much. In general, cycloate and S-metolachlor provide two effective options for preemergent weed control in spinach grown at highdensities on 80-inch wide beds. However, care must be taken to understand the characteristics of each material to achieve the best results. 9
WEED MANAGEMENT
Use of Cycloate and S-metolachlor for Weed Control in Spinach
WEED MANAGEMENT
Effects of Prometryn Applied in Cilantro Oleg Daugovish, Anna Howell, Steve Fennimore and John Rachuy (UC ANR) THE ISSUE: It took over a decade to secure the label for prometryn herbicide in cilantro with a lot of efficacy and residue work and support efforts that were coming in waves. Now that we finally have an effective weed control tool for cilantro, the questions about plant-back restrictions need to be addressed. The project: With support of manufacturer and IR-4 program (addressing minor use crops needing crop protection), UC weed scientists conducted studies to evaluate intervals after prometryn application for safety to four rotational vegetable crops. Methodology: At Santa Paula and Salinas, CA, we applied prometryn at 3.2 or 6.4 pint/A the day after Leisure cilantro was seeded. All plots, including untreated controls, were irrigated shortly after herbicide application. The experiments were designed as randomized completed blocks with four replications. At
50-55 days after planting, the cilantro was terminated and beds reshaped in preparation for following vegetable crops. At 60, 90 or 120 days after treatment (DAT) with prometryn within each plot we transplanted Brussels sprouts, bell peppers and Napa cabbage or seeded spinach at Santa Paula, while at Salinas both spinach and Napa cabbage were seeded. At both locations we evaluated weed control and injury to rotational vegetables at 2 and 4 weeks after planting them. Results: Prometryn reduced broadleaf weed number in cilantro 90-95% compared to untreated checks, but as expected had no effect on a deep-rooted perennial: field bindweed. At Santa Paula, no significant injury was observed in any of the following vegetable crops at all planting dates or herbicide rates. On a scale from 1 (no injury) to 10 (dead plants), we have not exceeded 2 in blind ratings of three staff evaluators in any plots. The stands of seeded
spinach had similar number of plants in all plots. This suggested that prometryn applied in cilantro may be safe to these rotational crops in warm clay-loam soil around Santa Paula. At Salinas, prometryn reduced broadleaf weed numbers in cilantro >99% compared to the nontreated check. Results from seeded spinach at 60-DAT are inconclusive, due to problems with background effects. Prometryn was safe on seeded Napa cabbage at 60-DAT / 43 days after planting (DAP). No reduction of stand occurred, and only slight injury at the 1.6 (low) and 3.2 lb ai/Ac (high) rates (3.1 and 3.8 ratings, respectively) were observed. Prometryn at 1.6 lb ai/ Ac was safe on transplanted Brussels sprouts at 60-DAT / 43-DAP. At the high rate of prometryn, Brussels sprouts showed no reduction in stand, but had moderate injury (4.6 rating). Both rates of prometryn were safe on transplanted bell peppers at 60-DAT, with no stand reduction and only slight injury (1.0 and 2.8 ratings) observed at 43-DAP.
Bell peppers and Brussel sprouts were among four rotational vegetables planted in different intervals after prometryn application in cilantro.
10
In Our Next Issue:
Impor ta nt from Ag information ricu Commiss lture io top Pest ners on the icide Vio lati and new DPR Wor ons ke Protecti on Stand r ards for 2018. Watch fo r this im por tant feature in our D ecember 2017 iss ue.
APPLICATOR ALERTS SEPTEMBER 2017 / VOL . I1, NO. 3
WEED MANAGEMENT Thank you to Brandt for their sponsorship of this Applicator Alerts issue and their continued CAPCA Platinum Sustaining Membership.
CAPCA 2300 River Plaza Dr., Ste 120 Sacramento, CA 95833
PRSRT STD US Postage PAID Tucson, AZ Permit No. 271
APPLICATOR ALERTS