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.
Lettuce field at Betteravia Farms, Santa Maria
Few herbicides are available for use in lettuce and more effective weed control tools are needed. Previous studies have found Prowl H2O (pendimethalin) to be safe to transplanted lettuce and effective on weeds that commonly infest lettuce fields. The study objective was to compare the safety and efficacy of pendimethalin applied to lettuce before (PRE) and after (POST) transplanting in commercial plantings and field station evaluations on the California central coast. Pendimethalin applied PRE transplanting resulted in little lettuce injury and provided acceptable weed control. Lettuce yields were not reduced by pendimethalin. While the level of injury was low with the pendimethalin POST transplant application, the PRE transplant application caused even less injury than the POST. Pendimethalin at 2.1 pt/Acapplied PRE or POST transplant controlled 68% and 53%, of the weeds, respectively, compared to 12% for Kerb (pronamide). In the commercial evaluations there was no difference in the numbers of marketable lettuce heads or head weights between pendimethalin and the hand weeded control. Results here show that pendimethalin has potential for use in transplanted lettuce and controls weeds as well or better than pronamide.
The objective of this work was to determine the safety of PRE and POST applications of pendimethalin to transplanted lettuce and efficacy on common weeds of lettuce.
Pendimethalin PRE and POST Applications. One month old lettuce plants (3 to 5 true leaf stage) were transplanted into twin row 40-inch wide beds. The in-row plant spacing was 9 inches, between row spacing was 12 inches and plots were one bed wide by 25 feet long. Prowl H2O 3.8 lb/Gal. (pendimethalin) was applied at 2.1 and 4.2 pts/A and Kerb 3.3 SC (pronamide) was applied at 2.5 pts/A PRE one day before transplanting and POST, one day after transplanting. The pendimethalin 2.1 pts/A treatment was included as the normal 1X rate, the 4.2 pts./A rate was included as a 2x rate to verify safety to lettuce. Each trial had a no herbicide non-weeded control and a weed-free control. Weed densities were measured in 2.8 ft2 sample areas about 3 weeks after transplanting. Crop injury estimates were recorded on a scale of 0% (no injury) to 100% (dead). Lettuce yield (fresh weights) was determined by harvesting a 9 feet long sample area from one plant line in the middle of the plot. Experiments were repeated in 2013 and 2014, and were arranged in a randomized complete block design with four replications. Injury, weed density and yield data were subjected to ANOVA and means were separated by Fisher's protected LSD at α ≤ 0.05.
Commercial Field Evaluation. The on-farm evaluations were held with cooperating growers in Las Lomas and Santa Maria. Pendimethalin was applied PRE at 2.1 pts/A one day before transplanting. Lettuce yield in Las Lomas was sampled from an 18 ft long sample area on one bed (4 plant lines). Lettuce yield in Santa Maria was sampled from one plant line by 30 feet long. The on-farm evaluations included a hand weeded control. Experiments were arranged in a randomized complete block design with three replications. Data were subjected to ANOVA and means were separated by Fisher's protected LSD at α ≤ 0.05.
Results and Discussion
Pendimethalin PRE and POST Applications. The PREpendimethalinapplications at 2.1 and 4.2 pts/Awere safe for transplanted lettuce and resulted in minor crop injury of 12% or less (Table 1). POST transplant applications of pendimethalin resulted in 0 to 7% injury in 2013. POST applications of pendimethalinin 2014 resulted in 22% and 24% injury for the 2.1 and 4.2 pts/Atreatments, respectively. While the level of injury was very low, injury was more evident in the POST transplant pendimethalin applications than in the PRE transplant applications. Lettuce yields were not reduced by PRE or POST pendimethalin or pronamide applications relative to the nontreated control, indicating that transplanted lettuce plants have similar levels of tolerance to both herbicides (Table 1).
The primary weeds in these experiments (average between 2013 and 2014) were 68% annual sowthistle (Sonchus oleraceus L.), 12% shepherd's-purse, 10% burning nettle (Urtica urens L.) and 8% hairy nightshade (Solanum physalifolium). Under high weed densities in 2013, pendimethalin at 2.1 pts/Aprovided 69% and 53% weed control respectively in the PRE and POST transplant treatments (Table 1). By comparison pronamide provided 12% and 39% weed control respectively in the PRE and POST transplant treatments. Annual sowthistle was the main weed in 2013; a species poorly controlled by pronamide. Hairy nightshade was the main weed in 2014, a species well controlled by pronamide, and the reason why pronamide performed better in 2014 than 2013.
Table 1: Injury estimates, transplanted lettuce yield (fresh weights) and total weed control resulting from pendimethalin PRE and POST applications, in 2013 and 2014 on the field station evaluations. Note: yields were combined for 2013 and 2014.
a Means with the same letter within columns are not significantly different according to Fisher's Protected LSD at P < 0.05.
b Visible injury estimates were taken 15 and 25 days after treatment for the 2013 and 2014 experiments, respectively; estimates were taken on a scale of 0%-100%, with 0% = no injury and 100% = dead plants.
c Yield was evaluated 48 and 59 days after treatment for the 2013 and 2014 experiments, respectively.
d Weed control was measured 25 and 23 days after treatment for the 2013 and 2014 experiments, respectively. The main weeds in this experiment were 68% annual sowthistle, 12% shepherd's-purse, 10% burning nettle and 8% hairy nightshade.
Commercial Field Results. Evaluations of pendimethalin in commercial fields found similar results to the research station evaluations. At both locations, there was no significant difference in the numbers of marketable lettuce heads or yield between pendimethalin and the hand weeded control (Table 2). Differences in yield between locations were mainly due to differences in lettuce varieties and corresponding cropping practice such as plant densities.
Table 2. Transplanted lettuce yield, number of marketable heads and fresh weights, from the on-farm study of pendimethalin held in Las Lomas and Santa Maria in 2013 and 2014, respectively.
a There were no differences between the treatments according to Fisher's Protected LSD at P < 0.05.
We concluded thatpendimethalin (PRE and POST) at 2.1 pts/Awas safe for use on transplanted lettuce, and resulted in better weed control than pronamide. For transplanted leaf lettuce, pendimethalin is a viable product and registration of this product on lettuce should be pursued.
Grower standard on the left and pendimethalin (Prowl H2O)-treated plots on the right at Babe Farms, Santa Maria
Acknowledgments: Thanks to California Leafy Greens Research Board for funding this study and Craig Sudyka, Betteravia Farms and Jason Gamble, Babe Farms, Santa Maria for their collaboration in Santa Maria studies.
UC Davis Rangeland Watershed Lab announced that Dr. Leslie Roche, formerly Lead Scientist at the Lab has accepted the offer from UC Davis Plant Sciences and UCCE as our new statewide Rangeland Management Specialist in Cooperative
Many of you have had the chance to meet Leslie prior to her appointment as she has been leading the California Ranch Stewardship Program. She fills the void left by Mel George who we in UCCE called "Uncle Mel". Perhaps she will become known as Auntie Leslie. Please welcome her in her new career!
I erroneously referred to requirements in some recently passed legislation related to direct marketing as "regulations". So I am posting an edited version of the blog. It also includes some additional information.
Recently Passed Legislation Related to Direct Marketing and Food Safety
California's Legislature recently passed several bills related to direct marketing and food safety. The California Department of Food and Agriculture (CDFA) has recently implemented some new requirements related to these bills. While these requirements could increase growers' costs, they also have the potential to foster more favorable market conditions for smaller farms engaged in direct marketing.
Some of the major provisions in these bills and their requirements are summarized below. It would be helpful for producers who direct market to review CDFA's Small Farm Food Safety Guidelines, http://www.cdfa.ca.gov/is/i_&_c/sffsg.html since they are referenced in all three pieces of legislation. Note that they are guidelines, rather than requirements. CDFA intends to revise them to be consistent with the federal Food Safety Modernization Act (FSMA) requirements, after the FDA has finalized the FSMA regulations (which I have heard could occur around October, 2015.)
Please note that this is NOT a complete listing of the requirements associated with AB 224, AB 1871 and AB 1990. I have added bold and italicized fonts to emphasize specific phrases. If you have any questions or concerns about these new regulations, please email me, Shermain Hardesty, Leader of the UC Small Farm Program, email@example.com.
AB 224 CSA Programs (Gordon—signed September 28, 2013)
- $75 annual fee, $25 for each amendment
- Registration form is in the CSA section of: http://www.cdfa.ca.gov/is/i_&_c/cfm.html
- The form requires producers to certify the following: “…to the best of my knowledge and belief, this report is true and complete. I further certify that I am knowledgeable and intend to produce in accordance with good agricultural practices as published by the department. See
http://www.cdfa.ca.gov/is/i_&_c/cfm.html for a copy of guidelines. I am aware I must also comply with any other local, state or federal laws.”
- Required CDFA to post Small Farm Food Safety Guidelines for crops on its website as mentioned above
- Required CDFA to post Food Safety Guidelines for processed potentially hazardous foods. Such foods fall under the jurisdiction of the California Department of Public Health and local health agencies, rather than CDFA. Thus, this will require inter-departmental coordination and could require significant time because the food safety requirements for such foods vary considerably
- Imposed specific requirements related to the labeling and maintenance of consumer boxes and containers that are used in CSA programs to deliver farm products in order to facilitate traceback
- Label the consumer box or container used to deliver farm products to the consumer with the name and address of the farm delivering the box or container
- Maintain the consumer boxes or containers in a condition that prevents contamination
- Inform consumers, either by including a printed list in the consumer box or container or by delivering a list electronically to the consumer, of the farm of origin of each item in the consumer box or container
- Maintain records that document the contents and origin of all of the items included in each consumer box or container, in accordance with department regulations
- Comply with all labeling and identification requirements for shell eggs and processed foods imposed pursuant to the provisions of the Health and Safety Code, including, but not limited to, the farm's name, physical address, and telephone number
- Specified that a registered California direct marketing producer is an approved source, subject to compliance with specified provisions of the law, and that any whole uncut fruit or vegetable or unrefrigerated shell egg grown or produced in compliance with all applicable federal, state, and local laws, regulations, and food safety guidelines shall be deemed to be from an approved source
AB 1871 Certified Farmers Markets (Dickinson—signed September 26, 2014)
- Required farmers to register with County Ag Dept. and pay a fee annually
- When farmers get their Certified Producers Certification for selling at Certified Farmers Markets, required them to attest that they are “knowledgeable of and intend to produce in accordance with 'good agricultural practices' (GAPs)--as outlined in CDFA's Small Farm Food Safety Guidelines mentioned above. CDFA will soon be adding a supplemental page to meet this requirement to either its online fill-in form or at the Ag Commissioner's office when producers pick up their certificates
- Required farmers selling at certified farmers markets to post a conspicuous sign or banner at their stand that identifies the farm/ranch by name, the county where the farm/ranch produces the products being offered for sale is located, and a statement that “We Grow What We Sell” or “We Raised What We Are Selling” or similar phrases that clearly represent that the farm or ranch is only selling agricultural products that they themselves have grown or raised on California land that they possess or control. Product sales by different farms at the same vendor stand shall separate the products from each farm or ranch and correspondingly post the required sign or banner in direct relationship with the sales display of the products produced by each farm.
- Authorized use of the term “California grown” and similar terms for marketing, advertising, or promotional purposes only to identify food or agricultural products that have been produced in the state or harvested in its surface or coastal waters, and made the fraudulent use of the term or a deliberately misleading or unwarranted use of the term a misdemeanor
AB 1990 Community Food Producers (Gordon—signed September 26, 2014)
- Defined “community food producers” as an approved source that includes, but is not limited to, community gardens, personal gardens, school gardens, and culinary gardens
- Unless a local jurisdiction adopts an ordinance regulating community food production or agricultural production that prohibits the activity, AB 1990 permits a community food producer or gleaner to sell or provide whole uncut fruits or vegetables, or unrefrigerated shell eggs, directly to the public, to a permitted restaurant, or a cottage food operation if the community food producer meets all of the following requirements in addition to any requirements imposed by an ordinance adopted by a local jurisdiction:
(2) Agricultural products shall be labeled with the name and address of the community food producer.
(3) Conspicuous signage shall be provided in lieu of a product label if the agricultural product is being sold by the community food producer on the site of production. The signage shall include, but not be limited to, the name and address of the community food producer.
(4) Best management practices as described in CDFA's Small Farm Food Safety Guidelines (as mentioned above), but not limited to, safe production, processing, and handling of both nonpotentially hazardous and potentially hazardous foods (see http://www.cdfa.ca.gov/is/i_&_c/sffsg.html)
(5) Egg production shall be limited to 15 dozen eggs per month.
- Permits a local city or county health enforcement office may require a community food producer or gleaner to register with the city or county and to provide specified information, including, but not limited to, their name, address, and telephone number
Please note that this is NOT a complete listing of the requirements associated with AB 224, AB 1871 or AB 1990.
Great news! Local shearer, Matt Gilbert has gotten approval for his new woolen mill. He expects to start processing wool in Ukiah by this fall. See the attached Ukiah Daily Journal article.