Pocket gophers stay active year-round wreaking havoc in vineyards and other irrigated land, but they can be particularly menacing in late winter or early spring when their breeding activity peaks. Thus, it’s crucial to think about management strategies now before it’s too late and populations are out of control.

Pocket gophers are rarely seen aboveground so calculating exact number of rodents in the vineyard can be difficult, but their burrow system is what gives them away. Under their obvious fan-shaped soil mounds over tunnel openings are typically hundreds of square feet of main tunnels with lateral branches.

In terms of damage, pocket gophers feed off vine taproots or belowground bark on vine trunks, killing young vines or reducing vigor on old ones if feeding is extensive enough. They also damage subsurface drip irrigation. According to UCCE Wildlife Specialist Roger Baldwin at the recent Grape and Wine meeting in November 2022, gopher mounds themselves can also kill vines, create weed seed beds and are a physical hazard in the vineyard.

Pocket gopher management, like most other forms of pest management, utilizes an integrated approach with different tools and strategies. “Mixing and matching these tools is generally going to give you a better result than if you were to rely on just one,” Baldwin said.

Currently available options for pocket gopher management include biocontrol, habitat modification, baiting, burrow fumigation and trapping. Repellent is one other option that may become more efficacious in the coming years.

Biocontrol with Barn Owls
Biocontrol is becoming more and more popular as an option for pest control today as chemical options continue to dwindle. In the case of pocket gophers, the barn owl, a predatory raptor species, will hunt them when present in the owl’s feeding territory; however, Baldwin said that barn owls are not a particularly territorial species.
While barn owls have been efficacious for control of other rodent types, results are inconclusive for pocket gophers. In vineyards, barn owl boxes can be erected to create a home for the owls to live in and breed.

“[Recent studies] have shown potential to reduce pocket gophers in a particular area, so that part is somewhat encouraging,” Baldwin said. “However, we do have to keep in mind that even if they provide some reduction in gophers, they’re certainly not going to eliminate gophers.

“That’s their food resource; if they eliminate it, they’ll have nothing to feed on.
“If you want to include them as part of an IPM program, I think that’s okay, that’s a good strategy, but I wouldn’t rely on them as your sole tool.”

Habitat Modification
Altering the desirable area for a particular species is the basis of habitat modification, Baldwin said, and pocket gophers utilize in-row cover and weeds as food sources.
In grape growing areas where gopher populations are high, it might be beneficial to remove cover crops and control weeds in order to reduce food for gophers. “It’s important to remember these nitrogen-fixing plants are good food sources for gophers and other rodents,” Baldwin said. “If you can shift away from some of these nitrogen-fixing plants to grasses that are less desirable, then that can potentially limit the densities of gophers that you get in a particular area.

Many vineyards utilize nitrogen-fixing cover crops as they provide multiple benefits to plant and soil health in the long term, so removing them to control gophers could be a detriment in certain situations, thus Baldwin noted it can be a balancing act of which benefit outweighs which negative more in a given vineyard.

Important to note is not just modifying the food source but also the burrows themselves for gopher management. Once gophers are controlled, their burrows remain, and new populations can spring up fast if they are allowed to use existing burrows to establish. Baldwin recommended deep ripping to remove burrow systems.

Repellents
In general, according to Baldwin, repellants have not worked well for controlling rodents in field or orchard settings, noting that often repellents require periodic reapplication in order to maintain efficacy, which can be costly and laborious.

One possible application for rodent control using repellents is reducing damage to surface drip irrigation (SDI) from pocket gophers. SDI has become a popular irrigation option throughout the state, but Baldwin said that gopher damage is one of the biggest hurdles for greater implementation.

“The depth of the drip tape is usually at the perfect level for gophers, so they come through and chew quite extensively on this drip tape,” he said. “This creates situations like substantial flooding which leads to all kinds of issues.”

Baldwin said that he and researchers have begun to look at the potential of running a repellent through the water during an irrigation event to move gophers out of a particular area. A product called Protec-T (active ingredient is methyl mercaptan) became registered in California within the last two years.

“We’ve just begun to look at the efficacy of this. What we’ve seen so far is a 41% reduction in gopher numbers. It’s not getting rid of gophers, but it is reducing the number in the field.”

Baldwin said that they haven’t studied this method enough to determine whether damage is reduced on SDI, but he believes that the possibility of damage reduction is promising.
“We haven’t had a chance to do it yet, but we need to measure the number of strikes on drip tape. That’s the most important thing that we need to measure right now,” he said.

Burrow Fumigation and Trapping
In the last few years, California has legalized carbon monoxide machines, sometimes referred to as pressurized exhaust machines, according to Baldwin, for burrowing rodent control. The devices inject carbon monoxide through hoses into burrowing systems and kill rodents.

Research conducted by Baldwin and others revealed that between 56% and 68% efficacy could be achieved for gophers across various soil conditions.

“The efficacy we observed with the PERC machine in dry soil conditions is much better than we would expect with more traditional burrow fumigants like gas cartridges or aluminum phosphide, and they seem to work as well or better than these same fumigants in ideal moist soil conditions,” Baldwin said. “So, I do think that these kinds of pressurized exhaust machines are probably very effective for ground squirrels and relatively effective for gophers.”

Trapping also appears to be highly efficacious in vineyards for pocket gophers. Traps are the most tried-and-true method of gopher control, Baldwin said.

“[In research], we saw 92% to 94% removal rates across two trapping sessions with the Gophinator trap,” Baldwin said, adding that trapping is also one of the most cost-effective control methods due to the high efficacy.

Whether your grapes are destined for wine, raisins, juice or the table, the job of the grapevine is to capture energy from the sun and use it to convert CO2 and H2O to carbohydrates and O2. Maximizing this process begins at budbreak and leads to larger, higher-quality crops. To have the greatest influence, a wholistic understanding of plant nutrition and crop production need to be engaged to ensure that every dime of fertilizer applied best serves its intended purpose. This is where the Five Rs of Plant Nutrition enters the decision-making process.

By combining knowledge from plant physiology, soil science, microbiology and chemistry, core principles of plant nutrition arise that affect fertilizer use efficiency, yield and quality. The Five Rs provide this science-driven approach in a memorable way that helps to confirm or guide nutritional decisions. A series of checks, the Five Rs ensure that the applied nutrients get into the plant when and where they are needed with minimal unintended nutrient interactions or losses. When framed as a question, the Five Rs can be stated as:

For my application, is this the:

• Right Nutrient?
• Right Time/Crop Stage?
• Right Form?
• Right Nutrient Mix?
• Right Place in the Plant?

The order of the Five Rs is easily re-organized to fit a given scenario, and when focusing on a specific growth period, considering the right time/crop stage first has the most value.

Right Time/Crop Stage
Early spring is a critical period for grapevine growth and development as the foundational support components of the plant and crop (xylem, phloem, initial leaves and new roots) are created. This timing is also very challenging because the ability of the plant to obtain and move the needed nutrients from the soil is hindered by low soil temperature and low atmospheric evaporative draw.

Cold soils inhibit microbial growth and function, preventing the cycling of nutrients from plant-unavailable to plant-available forms. Similarly, mineral solubility in the soil-water solution is also reduced as soil temperatures decline.

Evapotranspiration is the primary mechanism for the movement of nutrients between the soil and the plant. When air temperatures decrease, so does the amount of moisture a given volume of air can hold as does the rate that the air can cause evaporation. Coupled with the small surface area of new growth, very low levels of evapotranspiration result.

The classical thought that soil nutrient stores alone can support optimal plant growth and development early on is brought into doubt, and other fertility decisions need to be considered. Other non-evapotranspirational mechanisms exist within the plant to mobilize and move stored nutrients but should be viewed purely as supplemental.

Right Place in the Plant
Just as important as what nutrient to apply and when to apply it is identifying the most efficient or appropriate place in the plant for the application. As addressed above, early spring conditions result in the soil being a poor nutrient source with low delivery efficiency. Yet, nearly all nutrients found in or used by the plant over a growing season were sourced from the soil via the roots. So then why is “Right place in the plant” a core principle? When nutrient demand timing and nutrient delivery limitations meet, the end goal of maximizing economic yield focuses less on ‘where is the nutrient found?’ and more on ‘where are the nutrients needed and what is the best way to deliver them?’ Hint: The answer isn’t always via soil application.

For most nutrients, what is found in or applied to the soil meets the volume requirements of the plant, but often soil conditions during the demand period or interactions with other nutrients limit their availability. Even in soils with perfect nutrient conditions, periods still exist where only foliar nutrient applications can meet the limited window of nutrient demand. Post-budbreak is such a time and pre-bloom, bud differentiation, set and berry development, post-veraison and postharvest periods all see benefits from timely foliar applications. During these periods, foliar nutrient applications can achieve results that the soil cannot deliver. And to go a step further, foliarly applied nutrients can uniquely alter nutrient ratios or balances within the plant in ways that cannot be achieved economically, or potentially at all, through the soil.

However, just as the soil cannot deliver all nutrients at the right time, the volume of macronutrients needed cannot be delivered solely through foliar feeding. In the end, some combination of both foliar and soil-based applications for most nutrients will be necessary to meet the quantities and timing required for high-level production.

Right Form(ulation)
The soil and leaf environments to which nutrients are applied are extremely harsh, albeit in almost opposite ways. This article will not go into specifics, but generally, foliar applications dry quickly, are exposed to comparatively high oxygen concentrations and wide-ranging temperatures, and are bombarded with solar radiation. The soil, on the other hand, is very chemically and physically active at the molecular scale and is teaming with life that needs many of the nutrients for its life cycle that our plants require.

Nutrient products are available as various compounds that can be organized roughly into four formulation groups: insoluble salts, soluble salts, chelates and complexes. Ideal use scenarios can generally be defined for each formulation group, and nutrient stability and uptake performance rely heavily upon where (right place) they are applied.

The main points to understand are 1.) there is no “magic bullet” formulation possessing very high performance as a nutrient delivery vehicle in both soil and foliar applications; and 2.) something else is always competing with the plant to acquire applied nutrients or acting against the formulation of the nutrient, decreasing its availability to the plant.

Insoluble salts: carbonates, oxides, hydroxides
Nearly or completely insoluble in aqueous solutions but micronize well. Foliarly, they coat tissues like paint and are highly effective reflectors/blockers of sunlight. As such, they are often used to prevent sunburn or sunscald of plant tissues. Foliar nutrient delivery performance is very poor. Slow conversion to plant-available forms in the soil results in poor performance.

Soluble salts: sulfates, nitrates, acetates, chlorides
Soil applications usually perform very poorly, but low cost can offset the inefficiency. Foliar performance is poor as uptake is slow, and excess accumulation of the companion anions (SO4, NO3, C2H3O2, Cl) elicit stress responses in the plant or are otherwise problematic.

Chelates: EDTA, EDDHA, EDDHSA, citric acid, amino acids
Synthetic, EDTA-type and similar are generally large, highly water-soluble materials that perform exceptionally well in soil applications. They are toxic to plants and soil organisms, however, and can solubilize heavy metals in the soil, causing accumulation in plant tissues. They are not great foliars.

Conversely, citric and amino acid based chelates perform well when applied foliarly and are less toxic. Stability is an issue in soil applications compared to EDTA-type chelates.

Complexes: dextrose-lactose, mannitol, glucoheptonate, lignosulfonate
Poor performers in soil applications, these naturally derived materials make average to exceptional foliar delivery vehicles. Molecular weight and size of the complex affects performance. The complexing compounds of some offer carbon skeletons that are easily assimilated by the plant once the nutrient is removed.

Right Nutrient/Nutrient Mix
While not always grouped together, the right nutrient and the right nutrient mix are closely related. Plant nutrient demands fluctuate over the season, and nutrient-to-nutrient ratios shift subsequently. Nutrient-to-nutrient inhibitions, synergies, antagonisms and stimulations exist and must be accounted for as not all nutrients work well together in the plant at the same time.

In our budbreak to pre-bloom vineyard, demand for all nutrients except potassium are high, and calcium and phosphorus are both needed early on. But Ca and P antagonize each other, decreasing application and assimilation efficiency. So, which do we apply? If we assess the right time and right place components, foliar application of Ca makes sense since it moves exclusively with the transpiration stream and as is needed in the leaves to initiate cell division and develop cell walls. P on the other hand provides the energy needed for cell division and other growth functions to occur. Under ideal circumstances, we could apply P foliarly today and Ca foliarly in three to seven days and see the greatest benefit. Practicality doesn’t often allow for this type of application situation, and in our attempts to reduce the number of passes through the field, we must apply both simultaneously.

Tie-ups and antagonisms in real-world agriculture are inevitable and will occur in the spray tank and in the plant. But synergies and gains in efficiency and yield will occur from a little time, effort and application of the Five Rs into your nutritional program.

While “sustainable” is a common term in agriculture today, this was not the case in 1994 when a small group of vineyard growers got together on California’s Central Coast to talk about critical resource concerns like safe pest management, soil quality and farmworker training.

Nearly 30 years later, that small group of growers has expanded to include hundreds more, representing over 80,000 vineyard acres. They are members of the non-profit organization Vineyard Team. The organization continues to uphold the original growers’ mission: Bringing together experienced growers and researchers to educate the industry on sustainable winegrowing practices. Today, sustainability is accessible to growers across the globe through in-field meetings, digital resources and third-party certification.
Founders Dana Merrill of Mesa Vineyard Management, Steve McIntyre of Monterey Pacific and Don Ackerman of Constellation Brands reflect on three decades of sustainable research and education.

Evolution of Sustainability Concept
Consumers continue to prioritize their health and wellness as we enter the third year of the COVID-19 pandemic. But consumers’ health needs have evolved beyond the basics of physical wellbeing. With increasing concern for the future health of families, communities and the planet, many consumers are seeking brands and products that promise a better tomorrow. In a 2021 study conducted by Simon-Kucher & Partners, 85% of respondents indicated they have shifted towards purchasing sustainable products over the last five years.

One way the wine industry is meeting this demand is through certification. Programs like SIP Certified verify that the vineyard and winery are implementing practices that protect the people and planet. The process requires that growers and winemakers adhere to specific practices and complete audits with third-party inspectors to verify compliance.
“Within the industry and the world, sustainability has become a guide for best practices,” said Ackerman.

“Acceptance and participation have snowballed,” Merrill said. “Today, sustainability is a standard operating procedure. Most buyers expect a sustainability certification.”
Sustainability Just a Buzz Word?

Consumers today are growing increasingly environmentally conscious. WWF commissioned global research by Economist Intelligence Unit (EIU) in 2021 (An Eco Awakening) that found that searches for sustainable goods have increased globally by 71% since 2016.
Growers agree that certification is not just a marketing tactic. “We can do well by doing good,” Ackerman said.

Many certification programs began as an educational self-assessment tool. Today, certification enables winegrowers to better manage their practices. Regular peer reviews with university Extension programs and professors and industry experts ensure that the latest research and technology are incorporated into the SIP Certified program so participants implement new sustainable practices as they go through the certification process.

McIntyre reinforced that the goal of sustainability is to regularly improve at a farm level. “It is a competition with yourself.”

Wine consumer demand for sustainable products increases annually, and winegrowers should communicate their good work through certification to be visible to consumers who are looking for sustainable wines. Incorporating science-based best practices is good for the environment and communities and meets consumer demand.

Major Issues in Vineyard Sustainability Today
From integrated pest management (IPM) to irrigation efficiency to labor supply, farmers need to balance numerous issues that impact sustainability to bring a marketable product to consumers. At its core, sustainability is a holistic approach to the business of winegrowing. A single practice can have an impact on more than just one specific area of production. A generous employee benefits program will create labor stability for the vineyard and job stability for the employee. Decreasing irrigation reduces both water and electricity use.

When asked what they see as major issues in sustainability today, the founders mentioned the health and safety of workers, regenerative agriculture, technology and pest management. The resounding theme in all their responses was thinking about the cumulative impacts of a decision.

Sustainability encourages growers to consider multiple management options. Pest management is a great example of an area where the vineyard manager uses all the tools in the toolbox. IPM strategies begin with cultural practices like leafing to reduce mildew pressure. These kinds of practices in turn reduce the load of pesticides applied to the vineyard, which improves health and safety conditions for workers and often lowers costs to the vineyard.

“Farmers are continually looking for ways to do more with less,” McIntyre said. His company addresses weed control by using multipurpose equipment. This practice decreases tractor passes, thus burning less fuel and reducing pollution.

Merrill explained that good soil quality creates healthier plants so there is less need for chemical pest management. “Sustainability means farming the same ground hopefully forever because you have created a healthy system.”

Sustainability and the Ag/Urban Interface
In 2020, direct on-farm employment accounted for 2.6 million of the 19.7 million jobs related to the agricultural and food sectors, just 1.4% of total U.S. employment. Building relationships between agriculture and residential neighbors is very important because few people have direct experience with agriculture. Safe farming practices like night sprays that prevent drift and protect workers from heat stress can be misunderstood. When farmers proactively get to know their neighbors, they open the lines of communication. This builds trust that can mitigate conflict and misunderstandings.

“The more people understand sustainability, the better they feel about being a neighbor to a working farm,” Merrill said.

The requirements of being certified sustainable help to create good neighbors because sustainability necessitates consideration for the health and well-being of all members of the community. Ackerman believes that being considerate to neighbors is part of the ethos of sustainability.

“Sound farming practices protect the environment for neighbors and the community.”
Ultimately, sustainability helps farmers tell their story of stewardship.

The Future of Sustainability
In viticulture, sustainability is a grassroots movement. In three decades of promoting sustainable winegrowing, countless growers have told Vineyard Team that they continue their education, trial new practices, push the bar and get certified because, “It’s the right thing to do.” 30 years later, all three Vineyard Team founding members still see sustainability as the future because it is a doctrine that keeps evolving and improving so that winegrowers can have a positive impact on more acres, neighborhoods and communities for years to come.

In Jeff Bitter’s view, California’s wine grape industry can no longer rely on market patterns that were considered normal even five years ago.

Market dynamics are changing, making it harder to forecast the coming year, said Bitter, president of Allied Grape Growers. The marketing cooperative represents some 500 California producers and sells more than $100 million worth of grapes each year.
Since 2019, Bitter pointed out, yearly harvests have consistently fallen below the once-normal crush of 4 million tons. California’s ongoing drought and escalating input costs are eroding producers’ margins. Wine shipments remain flat. The struggling economy adds another layer of uncertainty.

“There’s apprehension in some wineries about what’s going to happen on the demand side,” he added.

Bitter isn’t alone in trying to gain a clearer outlook as the wine grape industry evolves.
“There’s a lot of guessing about what’s going to happen in 2023,” said Craig Ledbetter, vice president and partner with Vino Farms. The company owns and manages over 15,000 acres of wine grapes throughout California.

Supply Side Shift
The production drop that began with the 2019 wine grape crop “was a pivotal point in the California market in terms of supply, demand and balance,” Bitter said. “That drop had to do with one thing: oversupply. Many growers were unable to sell their grapes or excess tonnage and had to leave them on the vine to rot.”

The upshot was that many growers decided to pull out their vineyards or get out of the business. That reduced supply “a fair amount for the future,” Bitter added, because those acres were permanently removed.

Now, California’s 2022 wine grape harvest marks the state’s fourth consecutive crop to fall below 4 million tons. Both Ledbetter and Bitter estimate its volume at around 3.5 to 3.7 million tons, down 10% from an average crop. They attribute the decrease partly to the vineyard removals of the last couple of years. A late-spring frost in the Delta and Lodi growing regions and the statewide heat wave in late August and early September also hurt yields.

Yet the reductions in recent harvests can’t only be attributed to vineyard removals, according to Bitter. Longer term are questions about the effect of California’s drought on the size of future crops.

“Something else is going on that’s causing us to have shorter crops each year,” he noted. “So, you look at the drought and its lasting impact. Is the state’s capacity for 4 million tons over? Is the average crop size of 3.6 million tons the new normal? We’re in a flat market so we’re not looking for more supply. But it does point to the reality that farmers will have to become more productive in their vineyards if they’re going to continue dealing with issues outside of their control.”

Demand Remains a Question
Underlying the effect of California’s smaller wine grape supply is, of course, the demand for wine.

“On the surface, after three short crops, you’d think the market should be stable, even strong if you’re looking at depleting inventories,” Bitter said.

But the wine market is still trying to find its bearings in the wake of COVID-19. Pandemic restrictions shifted demand for wine away from restaurants, bars, sporting events and other public venues to supermarkets. While that hurt many businesses, those changing market channels created opportunities for lower-priced wines to regain some health. That benefitted grapes grown in the state’s interior regions, which generally produce the wine sold in grocery stores.

The boost in sales at the $15-per-bottle level and higher is important, since 70% or more of the entire wine market sells at the $20-per-bottle price point, Ledbetter said.

The big question now is how wine consumers will react in the coming year as economic uncertainty and fears of a recession persist.

“An economic decline won’t lead people to stop drinking wine, but they will trade down from their usual price points,” said Ledbetter. “If they typically drink a $35 bottle of wine, they’ll shift to a $20 bottle. That will help the lower end of the market.”

Among wineries, the flat wine market is leading to a greater focus on maintaining market share. It’s also driving more aggressive players “to try to steal someone else’s share of the pie,” Bitter said. “That’s where certain wineries and producers are growing. You don’t have a lot of strategy around growth or introducing new products or being the next greatest thing. It’s, ‘How do I maintain my portion in the market and operate my business without putting me at risk?’”

The industry also is grappling with how to market wine to different generations. The baby boomers, who helped drive market growth over the past few decades, have slowed their wine consumption.

“The biggest issue of our industry is trying to understand millennials [born from 1981 to 1996], who are the second largest segment of the U.S. population,” said Ledbetter. “They’ve been consistently inconsistent in their loyalty to wine.”

Export Optimism
Gino DiCaro, director of communications for Sacramento-based Wine Institute, said California wineries are optimistic about current and future demand for their unique and often sustainably grown and made wines.

“With a 10.6% increase in exports last year, we are seeing growing global demand, and domestically the direct-to-consumer (DTC) market has grown under expanded DTC channels,” he noted.

Wine Institute is the public policy advocacy group of 1,000 California wineries and affiliated businesses. It’s also the administrator of the USDA Market Access Program (MAP) for California vintners, representing 80% of U.S. wine production and 95% of U.S. wine exports. Under Wine Institute’s California Wine Export Program, more than 195 of the state’s wineries export to 142 countries.

“California’s wine-producing community is still growing,” DiCaro said, “which means we’ll be well suited to accommodate market demand for that coveted glass of Golden State wine.”
Grower-Side Pricing

Also coloring the 2023 wine grape outlook are growers’ high input costs. Soaring prices for fertilizer, labor, energy, parts and supplies as well as increased regulations have all raised producer expenses.

“The cost of putting in a vineyard in the Lodi area has increased 35% to 40% since COVID-19 arrived,” Ledbetter said. “The numbers no longer show a positive return on investment unless we see a dramatic increase in price. It’s very difficult to make money these days.”
Pricing needs to range from $800 to $850 a ton for Lodi area growers to be economically sustainable, Ledbetter added, versus the current $600 to $650 levels.

Bitter foresees pricing at the grower level remaining stable in 2023. But that’s not good news for growers. “Stable pricing means we’re going backward,” he said. “Input costs have been rising for the last 18 months and will continue to rise. The average grower today is less profitable than [they were] last year.”

Even so, growers like Ledbetter refuse to let their immediate challenges dim their outlook. They’re looking for opportunities to help them survive. To expand their options and sustain their farming future, for example, Ledbetter and his family have planted pistachio trees east of Galt and along Interstate 5 near Elk Grove between Stockton and Sacramento. But they aren’t leaving the wine grape business.

“I’m a farmer, so I’m optimistic,” Ledbetter said.