ACP Spread in Bakersfield Area, Ingenious Research Proceeds

Ingenious Research Effort to Fight ACP Spread with Natural Predators

By Joanne Lui, Associate Editor

Beth Grafton-Cardwell, Cooperative Extension specialist, University of California, Riverside Department of Entomology

As we have reported in-depth before on California Ag Today, the Asian Citrus Psyllid (ACP) is a tiny, mottled brown insect that poses an ever-increasing threat to the state’s robust citrus industry, as well as to residential citrus trees. The pest can spread a bacterium known as Huanglongbing (HLP) that is fatal to citrus trees. The disease has nearly shut down Florida’s citrus industry.

Beth Grafton-Cardwell, cooperative extension specialist in integrated pest management, UC Riverside Department of Entomology, explained the significance of the recent ACP spread to Bakersfield. “That is really problematic because it’s mostly in the urban areas. It’s very difficult to find, to control and to stop that spread. It’s going to move out from that region into the local citrus orchards, and so there are lots of meetings and discussions right now to mobilize growers to get treatments to help protect their citrus orchards against the psyllid.”

#CitrusMatters

To contain the ACP problem, Grafton-Cardwell stated, “There are traps everywhere, but the traps are not terribly efficient. So, we really need to carefully examine groves and flush [new leaf growth] for the nymph form,” she said.

According to Agriculture and Natural Resources, University of California’s Statewide Integrated Pest Management Program:

Adults typically live one to two months. Females lay tiny yellow-orange almond-shaped eggs in the folds of the newly developing “feather flush” leaves of citrus. Each female can lay several hundred eggs during her lifespan.

ACP (Source: ACP UC IPM)

The eggs hatch into nymphs that are wingless, flattened, yellow or orange to brownish, and 1/100 to 1/14 inch long. Nymphs molt four times, increasing in size with each nymphal stage (instar), before maturing into adult psyllids. The nymphs can feed only on soft, young leaf tissue and are found on immature leaves and stems of flush growth on citrus.

The nymphs remove sap from plant tissue when they feed and excrete a large quantity of sugary liquid (honeydew). Each nymph also produces a waxy tubule from its rear end to help clear the sugary waste product away from its body. The tubule’s shape—a curly tube with a bulb at the end—is unique to the Asian citrus psyllid and can be used to identify the insect.

Grafton-Cardwell and other experts are concerned because once the ACP becomes established in urban areas, it is difficult to eradicate. “It starts spreading into the commercial citrus, and we’re off and running,” she commented.

In a ingenious effort to control the spread of the psyllid, trained teams of entomologists have imported Tamarixia radiata, a tiny wasp that naturally preys on ACP, from Pakistan to research and release in California. A cooperative effort of the University of California Riverside, Citrus Research Board, United States Department of Agriculture and California Department of Food and Agriculture, researchers are also exploring the effectiveness of another beneficial insect called Diaphorencyrtus aligarhensis to assist Tamarixia with control of the Asian citrus psyllid. To see where Tamarixia and Diaphorencyrtus have been released, visit this University of California’s website map at, “Distribution of ACP, HLB and Parasites in California,” and turn on the parasite layers.
Grafton-Cardwell said, “They’re going to inundate that area,” with natural ACP predators, “so hopefully that will push back a little bit.”

California Ag Today2021-05-12T11:05:46-07:00October 10th, 2016|

Food Tank’s Farm Tank Summit in Sacramento Reveals Knowledge Gap

Food Tank’s 1st Annual Farm Tank Summit in Sacramento Reveals Gap in Agricultural Knowledge

Good Starting Point for Constructive Conversation

By Patrick Cavanaugh, Farm News Director

Several hundred food activists attended the First Annual Farm Tank Summit in Sacramento last week, hosted by Food Tank, in partnership with the Visit Sacramento, California Farm-to-Fork Program, and University of California, Davis. Danielle Nierenberg, co-founder and president of Food Tank noted having the event in Sacramento enabled West Coast agricultural experts to contribute to the discussion.

“We were really excited to feature California agriculture, because it’s such a huge part of the American economy,” said Nierenberg. “Californians are feeding the world, and we need to really highlight what these amazing producers are doing. When the Farm to Fork program of the Visitors Bureau reached out to us, we were thrilled to partner with such an amazing group of people, as well as UC Davis folks and the Center for Land-Based Learning,” she said.

Food Tank, an abbreviation of Food Think Tank, is a 501(c)3 non profit organization focused on building a global community for safe, healthy, nourished eaters that values education, inspiration and change.

According to their website:

Food Tank is for the 7 billion people who have to eat every day. We will offer solutions and environmentally sustainable ways of alleviating hunger, obesity, and poverty by creating a network of connections and information for all of us to consume and share. Food Tank is for farmers and producers, policy makers and government leaders, researchers and scientists, academics and journalists, and the funding and donor communities to collaborate on providing sustainable solutions for our most pressing environmental and social problems.

The organization begins with the premise, “Our food system is broken. Some people don’t have enough food, while others are eating too much. There’s only one way to fix this problem—and it starts with you and me.”

With the goal of feeding the hungry world of nine billion people in a few years, “Food Tank highlights hope and success in agriculture. We feature innovative ideas that are already working on the ground, in cities, in kitchens, in fields and in laboratories. These innovations need more attention, more research, and ultimately more funding to be replicated and scaled-up. And that is where we need you. We all need to work together to find solutions that nourish ourselves and protect the planet.”

Nierenberg clarified, “I don’t necessarily think we need to scale up food production; I think we need to scale out different innovations that are working. We’re wasting about 1.3 billion tons of food annually. That’s enough to feed everyone who’s hungry today, so we don’t necessarily need to ramp up production. We need to have better distribution, and processing practices that can help get food to people who need it the most,” she said.

“We need the political will behind those things,” she continued, “to build the infrastructure necessary for farmers to have better processing facilities, to have better storage facilities, to have better roads—if we’re talking about the developing world. I don’t necessarily think that we need to invest in producing more calories; we need better calories. We need more nutrient-dense food, and we need less starchy staple crops,” she noted.

Editor’s Note: Activists overtook the stage during the event, and the conversation was notably challenging for panelists. In an effort to Cultivate Common Ground to link consumers with the farmers who grow their nutritious food—and vice versa—California Ag Today has chosen to share some interesting statements from presenters and attendees to illustrate, perhaps, where the discussion could begin:

Regarding farms and processing facilities, big is bad, and small is good.

Regarding food quality, organic produce is healthy and safe, while conventional produce is unsafe and full of pesticides.

One of many moderators from the Bay Area, Twilight Greenaway, managing editor of Civil Eats mistakenly introduced Oscar Villegas, Yolo County Supervisor, District 1, as being from Sacramento County. When Villegas corrected her, Greenaway said, “I’m showing my Central Valley and Bay Area eliteness.”

Eric Holt-Giménez, executive director of Food First, noted that farmworkers are invisible in California agriculture. “There is racism in the fields. We need more worker unions and we need farmworkers to be paid much more than they are now and the farmworkers should be getting pensions from the farmer.”

Michael Dimock, president, Roots of Change, said to the audience, “You guys are doing a great job. Keep doing it. Keep working with your NGOs. They know policy. In turn, they can work with the legislators.”

“You need to be in the capital, pursuading the legislatures to support their bills. They want to be reelected, and if they don’t do what we ask them to do, they are scared.”

“In the meantime, we have to be nice to farmers because farmers are scared. We are putting a lot of pressure on them; They are in a vice. Our movement has supported bills AB 1066 – the overtime bill, minimum wage increases, organic farming legislation, and workers’ rights.”

Kerryn Gerety, founder and CEO, Lazoka, referred to John Purcell, vegetables global R&D Lead, Hawaii business lead, vice president and distinguished fellow, Monsanto Company, and said, “There is an elephant in the room, the Monsanto rep. Monsanto has all the technology patents. We all want transparency and we need you to be more transparent.”

Continuing, “Why doesn’t Monsanto open-source some of your patents and release the intellectual property so others can take advantage of your teçhnology?”

Purcell answered, “We are an Ag company. Why would our company invest a million dollars on technology and let everyone have it? It is our investment and we need to have the opportunity for a return on that investment.

During a panel discussion of food companies including Blue Apron, Almond Board of California, and Bayer CropScience, that covered organics, Jennifer Maloney, food chain sustainability manager, Bayer CropScience, said, “We do support the organic industry, because we have biological products that work in organic as well as conventional [farming].”

Maloney also talked about agricultural Integrated Pest Management (IPM) technology such as smart sprayers that spray only targeted areas.

Matt Wadiak, founder & COO, Blue Apron, responded, “It’s not about smart sprayers; it’s about biological systems in the field and trying to lean on them instead of spraying.”

Maloney replied, “Yes, that is exactly what IPM is.”

Keith Knopf, COO, Raley’s Family of Fine Stores, commented on the organic question, “the way we see organic versus inorganic—that is not the discussion for us. What’s more important to us is, is it the candy bar or the apple?”

This two-day event featured more than 35 speakers from the food and agriculture field, interactive panels moderated by top food journalists, networking, and delicious food, followed by a day of hands-on activities and opportunities for attendees. This was the second in a series of three 2016 Summits, following the Washington, D.C. Food Tank Summit that completely sold out and drew in more than 30,100 livestream viewers. The third Summit will be held in Chicago on November 16, 2016.

California Ag Today2021-05-12T11:05:46-07:00September 27th, 2016|

Eighteen New California Farm Academy Graduates!

Eighteen New Farmers Graduate from California Farm Academy

By Patrick Cavanaugh, Farm News Director

The California Farm Academy, a part-time, seven-month, beginning farmer training program run by the Land-Based Learning, graduated 18 new farmers on Sunday, September 18, 2016.

With more than 250 hours of classroom and field training behind them, these enterprising graduates were honored by notables such as Karen Ross, secretary, California Department of Food and Agriculture (CDFA); Craig McNamara, president and owner of Sierra Orchards, as well as president of the California State Board of Food and Agriculture; Sri Sethuratnam, director, California Farm Academy (CFA); and Mary Kimball, executive director, Center for Land-Based Learning, based in Winters California.

new farmers graduate from California Farm Academy beginning farmer training program run by the Land-Based Learning.

Eighteen new farmers graduated from California Farm Academy’s beginning farmer training program run by the Center for Land-Based Learning.

“The impetus of our program,” said Christine McMorrow, director of development for Land-Based Learning, “is the need for more farmers as the current ones age out. According to the USDA, over 700,000 new farmers will be needed in the next 20 years to replace those who retire.

CFA teachers, farmers, academic faculty and staff, and agricultural, natural resource and business professionals, teach CFA students basic production agricultural practices; crop planning; soil science; pest management; organic agriculture; irrigation and water management; marketing; ecology and conservation; obtaining loans, insurance and permits; farm financials; human resource management; risk management; farm safety; regulatory compliance and problem-solving.

McMorrow stated, “These folks have been with us since February, following a rigorous application process. A lot of these folks either have land they have dreamed of farming but did not know how to put it into production. Some of them come from farming families, but they wanted to get involved in the family business on their own. They may have been in a different career and now want to do something new or different. Perhaps they haven’t studied agriculture or they have not seen much agriculture other than what their family does, so this is an opportunity for them to learn and to explore a new business idea.

“We only take people who are serious about production agriculture. This is not a program for somebody who thinks, ‘I’ve got an acre in my backyard and I really want to grow something.’ While that’s a cool thing to do, the academy is not for those people.”

“Our graduating farmers, who range in age from their late 20s to early 50s, each wrote a business plan and presented it to folks within the agriculture industry,” said McMorrow. “They also planted some of their own crops on a farm in Winters.

McMorrow elaborated, “These new farmers have been able to create their own networks, having made contact with more than 40 different folks within the agricultural industry throughout the time they spent with us. These networks include local farmers around Yolo County, Solano County, Sacramento County, and other regions, and will help our graduates realize their dreams.”

“This is the fifth class that has graduated,” explained McMorrow, “and mind you, these folks are doing lots of different things. Some of them already have their own land, some are going to work for someone who has land, some will work other farmers, and some will go into a food-related business.”

“Still others will stay and lease small plots of land from us,” McMorrow commented, “to start their own farming business. Beginning farmers face huge barriers to getting started, the biggest of which is access to land, capital and infrastructure. So, to get their farming businesses started, California Farm Academy alumni are eligible to lease land at sites in West Sacramento, Davis and Winters at a very low cost.”

The Center for Land-Based Learning exists to cultivate opportunity.

For the land.

For youth.

For the environment.

For business.

For the economy.

For the future of agriculture.

California Ag Today2021-05-12T11:00:49-07:00September 19th, 2016|

Spider Mites Gave Almond Industry Reprieve in 2016

Spider Mites Showed up Late This Season

By Lauren Dutra, Associate Editor

This year, near-perennial spider mite pressure on almonds was delayed until hull-split. “That’s the big story this year,” said David Haviland, UC Cooperative Extension entomology farm advisor, Kern County. “The orchards of people who did early management programs well their fields looked great until hull-split. And the orchards of people who did not do anything well their fields looked great at hull-split as well—when the mites showed up,” he said.

Almond hull-split

“And a good population of them arrived,” Haviland continued. “People sprayed, but now we’re at the beginning of September, and everyone I have talked to in the Southern San Joaquin Valley have reported the arrival of the sixspotted thrip, a beneficial spider mite predator. The thrips came in fierce, cleaning out anything that didn’t get controlled prior to Nonpareil harvest,” said Haviland.

“We are on the tail end of the season in Kern County, and mites ought to be going away in a couple of weeks,” he said.

Haviland also explained the appearance of navel orangeworm this year is about average. “As far as navel orangeworm goes, things are looking good. They are certainly out there. They’re certainly in some nuts, but trap captures have been about normal, so—nothing really alarming in terms of numbers,” Haviland noted. “I haven’t heard of anybody really getting hit hard this year, other than some orchard edges here and there.”

“Growers seem to be happy. We are about halfway through the harvest, hoping the second half of almond-shaking goes just as well as the first,” said Haviland.

California Ag Today2021-05-12T11:02:58-07:00September 9th, 2016|

Weedy Rice Challenges Some Rice Growers

Weedy Rice Crops Ups Again in Northern Calif. Rice Fields

By Patrick Cavanaugh, Farm News Director

In Northern California, rice growers typically prepare to start harvesting in mid-September, but some growers have endured a lot of weed pressure from weedy rice (Oryza), also known as red rice, according to Whitney Brim-DeForest, a UC Cooperative Extension Rice Farm Advisor in Sutter, Yuba, Placer, and Sacramento Counties who focuses particularly on weeds. Red rice is actually the same species as cultivated rice, but it produces far fewer grains per plant and is therefore considered a pest.

Brim-DeForest said weedy rice is common in the Southeast, but not in California. “We’ve been pretty lucky in California in that we actually don’t have a big problem with it,” she said. “It’s a big problem down in the southern U.S. and they have been dealing with it in for a long time; but we have had it crop up. I think the last time was in 2006, and we managed to deal with it. It somehow popped up again in the last couple of years, so we’re dealing with it again.”

How weedy rice reached California is apparently a mystery. “We don’t really know the source of it, to be honest,” said Brim-DeForest. “We’re investigating that through research, hopefully starting this fall,” she said.

Brim-DeForest said growers have few choices to control weedy rice. “Growers that have it will either have to rogue¹ it out, pull it out by hand or sacrifice that field and spray it with Roundup,” she said, “which would kill the rice as well. And, if the rice grower doesn’t know he has weedy rice in the field, it could hurt him later at the rice mill,” explained Brim-DeForest.

“Once harvested, the rice goes to the mill. If a certain amount of red rice bran (the outer layer surrounding the rice grain) is discovered, the mill will not accept it and could reject the entire load,” she said.

¹rogue (verb) to remove inferior or unwanted plants

California Ag Today2021-05-12T11:05:48-07:00September 2nd, 2016|

CULTIVATING COMMON GROUND: Economic Analysis of Drought on California Agriculture

Editor’s note: We thank Aubrey Bettencourt for her contribution to California Ag Today’s CULTIVATING COMMON GROUND commenting on the report, “Economic Analysis of the 2016 Drought for California Agriculture,” released this week. Lead UC Davis author Josué Medellín-Azuara’s response can be read below.

By Aubrey Bettencourt, executive director, California Water Alliance (CalWA)

Josué Medellín-Azuara, Duncan MacEwan, Richard E. Howitt, Daniel A. Sumner and Jay R. Lund of the UC Davis Center for Watershed Sciences, ERA Economics and the UC Agricultural Issues Center reported their views on the economic impact of California’s continuing drought on agriculture this week. The study, “Economic Analysis of the 2016 Drought For California Agriculture,” proved to be uncommonly riddled with errors, questionable metrics and inaccuracies; it’s a continuation of a disturbing recent trend.

The authors claim that about 78,800 acres of land might be idled due to the drought, but a quick Google search shows a single water district that had more than 200,000 acres of fallowed land in 2016. There are more than a hundred other water districts throughout the state, and most are reporting idled acreage.

In another irrigation district in Yuba County, more than 100 agricultural users have been cut off entirely, leaving their nearly-mature crops and fruit and nut trees without water. [North Yuba Water District (NYWD)]

This year the federal and state water projects announced they would provide agriculture with 55% of their water. Two months ago, they reduced the estimate to 5% south of the Delta, and they are struggling to even deliver that amount.

Across the state, water prices have increased dramatically, whether pumped from the ground or bought on the faltering water-exchange market. Water that costs less than $250 per acre foot in 2012 now costs up to $750 or more.

It doesn’t take a doctoral or economic degree to understand that when the price of water goes up, the cost to produce food also goes up. Farmers may be getting more money for the produce they grow, but they are watching their bottom line shrink because it costs more to grow it. Even water from their wells isn’t free; pumping takes energy, and energy costs money too.

Adding to rapidly increasing costs are the new minimum wage, capped work hours, and hundreds of regulatory mandates from the 80+ local, state, and federal agencies that oversee every aspect of California farming and bury farmers in paperwork and red tape. Compliance takes time away from growing food, and it costs money.

Take a look at rice farmers. Growing rice today is a losing proposition. After the labor, cost of rice plants, fuel, fertilizing, care, harvesting, drying and milling, growers pay substantially more to grow rice than they can charge for their crop. Many have converted rice paddies to other uses, and some sell their water or take money from federal agencies and conservation groups to create wildlife habitat in order to simply stay afloat. Some are selling off their land to developers, a lose-lose decision affecting everyone.

On main street, consumers are another group taking a second, alarmed look at their grocery, water and sewage bills. All are rising far faster than inflation. Whether you are talking about the price of fruit, bread and eggs or the cost of taking a shower, all have been increasing over the past five years because of the drought.

To really understand what’s happening, take a drive out of the city and into the countryside where your food is grown. Stop at a roadside produce stand or park your car and strike up a conversation with some ranchers and farmers in a small town cafe.

After you hear their stories, you may realize that almonds and pistachios are not as labor intensive as strawberries, tomatoes, cucumbers, grapes, beef, lamb or many others out of the nearly 450 crops grown in California. Some crops are thirstier than others, too. This doesn’t diminish the value of these fruits, nuts, vegetables, and proteins. The value of water is what it provides us: in this case, safe, local, and hopefully affordable food.

But commonsense interviews and case studies of actual operations — once the heart of any competent agricultural economic study — are virtually missing from the report’s statistical models built on university computers, research hypotheses and tables of statistics.

The drought has hurt California farmers, and it is hurting Californians wherever they live. Gross income may be up, but net profits are down, and the rate of decline hasn’t hit bottom yet.

Aubrey Bettencourt is the executive director of the California Water Alliance (CalWA), a leading educational voice and authority on California water. CalWA advocates for the water needs of California families, cities, businesses, farmers and the environment.

Editor’s note: California Ag today thanks Josué Medellín-Azuara, senior researcher, UC Davis Center for Watershed Sciences, and lead author of “Economic Analysis of the 2016 Drought For California Agriculture,” published this week, for his response to several claims made by Aubrey Bettencourt (above).

Josué Medellín-Azuara told California Ag Today, “I will not go over debating the comments which I very much welcome and respect, but I would like to provide some thoughts instead.”

1) “Through remote sensing,” Medellín-Azuara said, “we estimated summer idle land in Westlands by the end of the irrigation season to have been 170K acres in 2011 and just above 270K acres in 2014,” based on NASA data. The difference can be explained by some drought effects and other conditions, according to Medellín-Azuara, “so idled land differences should be taken with a grain of salt. As a point of interest, most of the fallow land we estimated was on the Westside of the south San Joaquin Valley.”

2) In addition, Medellín-Azuara clarified, “My understanding is that there is a cost issue and a cutoff issue. We estimated about 150 TAF (Thousand Acre-Feet) of [water] shortage in the Sacramento Valley in our study. At current conditions for North Yuba Water District (NYWD) agriculture is no more than 3 TAF from my reading of the attached document. I am not saying the cutoffs are not hard for the more than a hundred users, but [I] also want to put numbers into perspective.”

3) “From what I’ve heard and read,” Medellín-Azuara stated, “the timing [of] more than quantity of the projected releases is unfortunate. One of the things we highly encourage in this and past reports is easing of low environmental impact water transfers among users.”

California Ag Today2021-05-12T11:05:48-07:00August 22nd, 2016|

Jamming Leafhopper Signals

Jamming Leafhopper Signals to Reduce Insect Populations that Vector Plant Disease

By Patrick Cavanaugh, Farm News Director

An innovative team of researchers at the San Joaquin Valley Agricultural Sciences Center, USDA Agricultural Research Services (ARS) in Parlier Calif., are trying to confuse leafhopper communication in hopes of reducing certain devastating plant diseases. Of particular interest is the glassy-winged sharpshooter, a large leafhopper that can vector or spread the bacteria Xylella fastidiosa from one plant to another which causes devastating plant diseases such as Pierce’s disease in grapes and almond leaf scorch.

Dr. Rodrigo Krugner, a research entomologist on the USDA-ARS Parlier team since 2007, explained, “We started on this glassy-winged sharpshooter communication project about two years ago. These insects use substrate-borne vibrations, or sounds, to talk to, identify and locate each other; actually do courtship; and then mate,” Krugner said.

Click here to hear LEAFHOPPER SOUNDS!

Glassywinged Sharp Shooter

“This area of research started probably 40, or 50 years ago with development of a commercially-available laser doppler vibrometer (LDV), a scientific instrument used to make non-contact vibration measurements of a surface,” Krugner said. “Commonly used in the automotive and aerospace engineering industries, the LDV enabled an entomologist to listen to and amplify leafhoppers communicating,” Krugner said. “We’ve been doing recordings in the laboratory, learning about their communication with the idea of breaking, or disrupting, that communication. Once we disrupt that, we can disrupt mating and thereby reduce their numbers in vineyards and among other crops.”

Krugner noted the research team is evaluating two different approaches: one is to discover signals that disrupt their communication, and the other is lure them away from crops or towards a trap. “We may be looking at female calls, for example. An analogous system would be the pheromones, or long-range attraction volatile chemicals released by female lepidoptera, to attract males.” However, since leafhoppers use only sound, Krugner said, “We’re trying to come up with signals to disrupt their mating communication. We’re also looking at signals to jam their frequency range, 4000-6000 Hz, so they cannot hear each other,” Kruger said. “We’re also looking at signals that can be used to aggregate them, or lure them, into one section of a crop, or maybe repel them from the crop. These are all different approaches that we’re investigating right now.”

Krugner explained, “Researchers are attempting to perfect the disruptive sounds in order to do the things we need—to actually implement a management strategy for disrupting not only glassy-winged sharpshooter, but anything in a vineyard that actually communicates using vibrational communication. We know what they are saying to each other, which is very important. In the laboratory, the signals that we have look promising in disrupting the communication of these insects, so we’re taking them into the field.

Current mating disruption trials are underway in Fresno State vineyards. “We’re going to finish that research, hopefully, next year,” said Krugner, adding, “usually, fieldwork takes two to three years to show something.”

(Featured photo: Rodrigo Krugner, research entomologist, USDA-ARS, Parlier)

California Ag Today2021-05-12T11:05:49-07:00August 15th, 2016|

Vigilant Seed Bank Reduction for Weed Control

Vigilant Seed Bank Reduction: Whatever it takes, don’t let weeds set seed.

By Patrick Cavanaugh, Farm News Director

For the past 15 years, Robert Norris, professor emeritus and vegetable crops weed specialist, UC Davis Department of Plant Sciences, has continued to attend Weed Day each year at UC Davis and to contribute weed photography for CalPhotos, a UC Berkeley Digital Library Project photo database of world-wide plants, animals, landscapes, and other natural history subjects developed to provide a testbed of digital images for computer science researchers to study digital image retrieval techniques. Norris was involved with initiating the Plant Protection and Pest Management Graduate Program at UC Davis.

“I’ve been a botanist since I was 14 years old,” Norris said, “and I still have a lot of passion regarding weed control.” Norris has a strong and steady philosophy on weed control and it all comes down to seeds. “The last 25 years of my work, I looked at population dynamics of weeds, like seed longevity in the soil and what we call the size of the seed bank also known as the seed production by weeds. That’s really where I spent most of my time.

Field Bindweed

“I found that most people have a very poor idea of how many seeds are produced by a weed. This led me to question some of our current management philosophies; namely, the one that comes out of entomology—the use of thresholds (or how many weeds need to be present before treating them),” noted Norris. “I felt that for weed science, thresholds were not the way to go, and my position has been vindicated by the problems we’ve run into using thresholds.”

Norris offered the example, “Barnyard grasses are probably one of our most serious summer grass weeds. A small plant can produce 100,000 seeds; while a big plant, well over a million. I can remember going put in a tomato field years ago and looking at one barnyard grass plant. Because I had been working with it, I can say that plant probably put out 50,000 seeds. If you spread those seeds around an acre, that’s enough to give you serious yield loss the next year,” Norris explained. “Again, that’s one plant, spread out over an acre. Obviously its seeds wouldn’t spread over an acre [on their own], but with our tillage equipment we would move it around quite a bit.”

“My bottom line for about 30 years now is: Don’t let the weeds set seed. Whatever it takes, don’t let them set seed,” Norris said. If you follow that philosophy, Norris said after a while you drive the seed bank down.

“Many people don’t realize this, but some of our really big growers got on to it a long time ago. One farming operation I worked with for years, J. G. Boswell Co., with most of its land in Kings County. “I knew the manager in the late ’50s, into the ’70s. He now is retired now, but he came to this conclusion himself back in the late ’50s,” Norris said. “I haven’t been on Boswell’s property now for 20 years, because I retired. However, if you go down there, you will not see a weed problem, at least not like most growers.”

“The difficulty really is, in order to carry out this philosophy, you need to use hand labor for weed management and it is becoming less and less easy to find,” explained Norris. “Most weed management is done on a one-year one-crop basis; whereas, the type of management we’re talking about where we’re really thinking seed bank dynamics, has to be done over multiple years. Another big problem that I still see is if you miss one year, you can undo 5 to 10 years of what you’ve just been doing, because of this high seed output,” he said.

NEVER LET ‘EM SET SEED, by Robert Norris, Weed Science Society of America.

California Ag Today2021-05-12T11:05:50-07:00August 8th, 2016|

Mechanical Weeding Would Help Veg Industry

Mechanical Weeding Saves Labor

By Patrick Cavanaugh, Farm News Director

A machine that mechanically removes weeds from the rows of lettuce and other crops and thereby saves costly labor bills, is now commercially available. “The Robovator, made by F. Poulsen Engineering ApS in Denmark, works amazingly well,” said Steve Fennimore, weed specialist, UC Agricultural and Natural Resources Cooperative Extension, Salinas. Fennimore said companies in Scandinavia have had more incentive to develop labor-saving machines after having faced many major labor shortages, as well as significant restrictions on pesticide use throughout the European Union, including the use of herbicides.

Meanwhile, significant domestic demand for organic tomatoes and tomato sauce makes hand-weeding especially necessary. California fields of tomatoes and lettuce, among other crops, often have lines of workers using hoes to briskly cut away the weeds or thin the crop. “Including thinning, there are three passes of labor in organic lettuce,” said Fennimore.

Steve Fennimore UC Davis Dept. Veg Crops and Weed Science, Salinas 1-1-1

Steve Fennimore researches alternative methods of weed control.

“The Robovator is an intelligent machine with cameras and a computer processor onboard to direct reciprocating knives to open and close,” Fennimore began. “It can follow the pattern in the plant line and the knife mechanism moves sideways (in and out) as it goes down the row. The knives delve generally ¾ inch into the ground, open as they pass a tomato or lettuce plant and close in between to dig up the weed.”

“It worked really well in the lettuce plants,” Fennimore commented, “where you have that 18-inch spacing, double planted on a bed. Everything was going so well in the double-row bed, we told the tractor driver to kick it up a notch and see what we could do—of course, with the grower right there,” Fennimore said. “So he stepped on it and got up to five mph. It was so fast that we could not see the knives move,” he said.

“I don’t think it is totally perfected, but it is commercially good,” said Fennimore. “Of course everything can be improved, but unlike an herbicide— which is a molecule that you cannot alter— this is a machine that can be modified. You can make the knives longer or bend a shoe a little to get better performance, which is nice,” he added.

“If you get the weeds when they are small, such as nightshade, pigweed, or purslane, the machine just pops them right out of the ground, flipping them upside down so their roots are up. In Europe, especially on organic lettuce where they cannot use herbicides, producers typically send in a crew with hoes as often as once per week, and it’s an expensive labor force. Instead, growers are letting the crop grow, coming through with the machine every 7 to 10 days to kill emerging weed flushes and doing a great job,” said Fennimore.

“So far, we have used the machine on tomatoes, broccoli, lettuce and celery here,” he listed, “and we are starting to look at peppers. And I know that the Europeans have used it in cabbage, onions, and radishes. The machine has done a good job without injuring the plants. With transplanted tomatoes, the plants are much bigger than the cotyledon stage of a weed [before it reaches one inch in height]. So the knives stay open around tomato plants but then close over the weeds, which basically uproots them.”

“You always have to be aware of the safety zone,” Fennimore cautioned. “If the crop is getting bigger and has roots near the surface, the knives need to stay back and you will not get all the weeds. The problem weeds in a halo right around the plant stem are the most difficult and most expensive to get. If you force the knifes in and try to get really close, you will probably not be able to go five mph. You will have to go slower to allow the machine to kick out the weeds near the stem.”

Fennimore mentioned two Poulsen ApS machines are presently in use in California and another mechanical weeding machine made by Steketee IC (intelligent cultivator) from The Netherlands is being tested in the Salinas Valley,” Fennimore noted. Teams are attempting to determine how the machine could be improved for use here, and the machines are becoming available for growers to test.

The biggest crowd that has observed the Poulsen Robovator was at the UC Davis Weed Day in 2015. “We have also been going to individual farms, showing it to farmers and explaining what it does,” said Fennimore. “We brought the machine to a Ventura lettuce farm about a month ago, and a few weeks ago we had it in tomatoes,” he noted.

With tomatoes, we are looking at less than 10,000 plants per acre,” Fennimore said, “so we can go about 5 mph in the tomatoes because the knives do not have to open and close as fast. However, with lettuce, we are looking at maybe 60,000 plants per acre, so you would have to go more slowly, around 1-2 mph in lettuce.”

Even on conventional vegetable farms, hand-hoeing is often done due to the lack of adequate herbicides. “We do not have a good spectrum of coverage,” said Fennimore, “and there are unsolved weed problems that are going to be hard to untangle.”

The development cost of the original machine prototype, the most expensive phase, was $11 to 15 million, as compared to the $250 to 300 million necessary to get an herbicide to label. And since 2010, only four new active herbicide ingredients have been developed worldwide. For lettuce applications, the last new herbicide was introduced about 40 years ago.

Yet another machine in development that Fennimore recently read about is essentially a weed-punch machine with electronics by Deepfield Robotics, a Bosch start-up company in Germany. “These guys drive through the fields, the machine finds the weeds and instantly punches them dead-center into the ground,” he elaborated.

Fennimore considered using such machinery on fields of garlic, onions or spinach that are densely planted, where back and forth knives would not work well. He theorized that machinery that can distinguished the weeds from the crop might work simply by punching the weed down into the soil where it’s not going to thrive. But perfecting this prototype is going very slowly, as it must accommodate a variation of cameras, weeds and crops. Yet, Fennimore expressed optimism, “I see a lot of potential with this type of technology because it can be modified.”

California Ag Today2021-05-12T11:02:59-07:00August 4th, 2016|

Mathesius is New UC Soil Scientist

Mathesius is New Agronomy Farm Advisor in Sutter-Yuba, Colusa Counties

By Patrick Cavanaugh, Farm News Director

Konrad Mathesius is the new Agronomy farm advisor at the UC Division of Agriculture and Natural Resources Cooperative Extension, Sutter-Yuba, Colusa Counties. Mathesius first explained his unusual last name. “It means ‘mathematics’ in Latin. I guess we had accountants in our family lineage back there somewhere,” he said.

Mathesius completed his undergrad degree in political science at Utah State, followed by two master’s degrees at UC Davis in Soils and Biogeochemistry; and in International Agricultural Development (IAD)—a graduate group within the Department of Plant Sciences. “The IAD is flexible in its curriculum, which allowed me to take many plant- and soil- specific courses. I took the opportunity at IAD to specialize in soils,” he said.

California Safflower Field

“Through the years, we have learned a lot through the pioneers of soil science and it’s an exciting field because there is still a lot to learn,” said Mathesius. “And everything that comes out of soil science, in one way or another, is applicable to life on the planet.”

“Soils also tell a story, and that’s one thing I really enjoy about it. It’s especially evident in California because there is a remarkable combination of parent material that has created an abundance of different soils in the state,” noted Mathesius. “And it’s very relevant to agriculture, ecology, and environmental science. Differences in soils create a stark contrast in how crops grow and how they need to be managed,” he said.

Mathesius is responsible for the agronomic crops grown in his region, including dry beans, oilseeds such as safflower and sunflower, fresh market corn and silage corn, and small grains such as barley, wheat, and rye.

“I’m a soil scientist by trade, but ultimately I am a UC Cooperative Extension Farm Advisor and available to growers to figure out what their crop issues are—which include pests, diseases and soil fertility,” noted Mathesius. “I am a resource, and the UC system has many other resources and personnel who can thoughtfully consider solutions to crop problems.”

California Ag Today2021-05-12T11:05:51-07:00July 26th, 2016|