Table grapes, as distinct from wine grapes, are grapes who’s primary purpose is to be eaten fresh, though table grape varieties may be used for juicing, raisins, or in other processed forms. Table grapes tend to be larger, have thinner skins, and a firmer texture than wine grapes. They are also more likely to be seedless.
Market Size
Global Table Grape Production
According to Food and Agriculture Organization of the United Nations, the world production of grapes in 2022 was 74.942 million metric tons, down 2.4% over 2021, with production led by the China, Italy, France, and India. According to the International Organisation of Vine and Wine (OIV), 7.2 million hectares of grapes were grown worldwide in 2023, which represents the third consecutive year of shrinking vineyard footprint. This figure includes both table grapes and wine grapes, as well as grapes used for other purposes such as grape juice, raisins, and grape seed oil. Because FAO statistics, and other industry data, do not differentiate between table grapes and wine grapes, this information is of limited utility for understanding the scope of the table grape market.
Source: State of the Vine and Wine Sector
According to USDA’s Foreign Agricultural Services, world table grape production is forecast to be up in the 2023/2024 marketing year to 28.1 million metric tons (though global exports are expected to be stagnant). This will mark the fifth consecutive year of growth in production for table grapes, in line with a trend of increasing global production that started in 2000, and which has lead to a doubling of table grape production in two decades. USDA also determined that the total table grape production of the top 5 producing countries in 2023; China, India, Türkiye, Brazil, and Uzbekistan, represented 78% of the global table grape total.
*Note that there is often meaningful discrepancies between USDA data, FAO data, and other data sources. This is a trend in specialty crop data reporting in general. As with all data, there’s an acceptable error range here that should be considered when manipulating these figures to calculate addressable market projections.
Country | Production (tons, 2023/2024) | Percentage of total global crop production (2023/2024) |
China | 13.5 Million | 48% |
India | 2.95 Million | 11% |
TĂĽrkiye | 1.9 Million | 7% |
Brazil | 1.75 Million | 6% |
Uzbekistan | 1.7 Million | 6% |
Egypt | 1.57 Million | 6% |
European Union | 1.3 Million | 5% |
Peru | 775,500 | 3% |
USA | 654,897 | 2% |
Chile | 635,000 | 2% |
Source: USDA Foreign Agricultural Service
Though China is by far the largest producer of table grapes globally, they have only recently become a leading exporter, and only in the 2023/3024 marketing year overtook Chile to become the second largest exporter of table grapes in the world (following Peru). In 2023, more than half of the table grapes consumed in the US were imported, mainly from Central and South America.
FIGURE: 2018 Breakdown of global grape production by quantity, country, and type
Domestic Table Grape Production
According to the California Table Grape Commission, in 2022, California table grape growers, who grow 99% of all US table grapes, harvested 95.1 million boxes of grapes for domestic consumption (70%) and export markets (30%). The California Department of Food and Agriculture estimates that there were 120,000 acres of bearing and non-bearing table grape vineyards in the state in 2022, down 8,000 acres from 2021. This production represents approximately 330 unique farms.
According to the United States Department of Agriculture (USDA), the total (sales) value of table grape production in the United States in 2022 was $1.53 billion. The total value of exported US table grapes in 2022 was $658 million, down 1.4% from 2021. The average price of a ton of table grapes in California in 2022 was $214.13 up 17.1% from 2021. In 2023, the US crop was significantly impacted by Hurricane Hilary, which struck during critical harvest periods.
“The US [table grape] market has seen slight but steady growth in recent years. In the 2019 season, it grew more than 12%, reaching 3.3 billion pounds. In the latter part of 2020 it declined 4.7%, falling to 2.9 billion pounds, partly as a result of the pandemic and consumption declines due to the lockdown, seen in April and May. Despite a strong recovery in June, it contracted again in July. In the 2020-2021 season the decline continued in autumn. However, beginning in December 2020 each week saw robust growth for the remainder of the season, reaching 3.2 billion pounds of fruit, a growth of more than 13%. In the 2021-2022 season it continued to grow, reaching 3.53 billion pounds, more than 7% higher than the previous season.” —International Fresh Produce Association, U.S. Grape Market Report: 2021-2022
The California Table Grape Commission's annual crop report for 2020 indicates that the San Joaquin Valley produced 1,020,225 tons of table grapes, representing approximately 94% of California's total table grape production. The remaining 6% came from the Coachella Valley, which produced 67,000 tons of table grapes that year. Arizona, Texas, and Florida are also home to some sparse and occasional grape production. The California Department of Food and Agriculture estimates that there are 125,000 total table grape acres in California in 2023 (120,000 bearing, 5,000 non-bearing). These acres are concentrated in the Coachella (Riverside and Imperial counties) and San Joaquin (Fresno, Kern, Tulare, and Madera counties) Valleys.
Based on industry estimates and historical data, it's estimated that California produces between 100 and 120 million boxes of table grapes each year, with each box weighing about 19-22 pounds. This means that California's total annual table grape production ranges from approximately 1.9 to 2.6 billion pounds (or 0.9 to 1.2 million tons).
Varietals
Though the exact number and mix of table grape varieties grown in the US changes from year to year, there are about approximately 79 table grape varietals that are commonly planted commercially (an increase from 39 in 2000). Flame Seedless was the leading table-type grape variety. The three broad categories of table grape varieties are white, red, and black, and though black varieties are a distant third in terms of popularity with consumers, their appeal seems to be increasing.
An early-season, red, seedless table grape that produces medium-sized, round berries. Clusters are conical in shape, medium in size and ripen in early July. This variety is vigorous and not very susceptible to root rot, and has long shoots and a horizontal bearing that require significant trellising. This variety tends to mature relatively early and is usually pruned long, meaning relatively more of the plant is left behind (rather than removed) during the pruning process.
For the latest (2023) data on total acreage planted to, average price paid for, and total quantity of this variety produced, see the California Grape Acreage Report, 2023.
The most widely planted grape in California, is a medium-sized, cylindrical-shaped, white grape that ripens in early to mid-August (in the San Joaquin Valley). The plant produces heavily shouldered clusters that ripen in early to mid-August in the San Joaquin Valley. This variety is most commonly used to make raisins (accounting for about 70% of total acres), though about 15% of total acres is dedicated to table grape production. This variety has multiple uses, and is planted in California for end-uses besides fresh consumption (i.e. raisins, juicing).
For the latest (2023) data on total acreage planted to, average price paid for, and total quantity of this variety produced, see the California Grape Acreage Report, 2023.
A mid-season, red, seedless table grape, this cultivar produces large, conical-shaped clusters and is relatively vigorous. These grapes are ready for harvest in mid-to-late August, filling the harvest window between Flame Seedless and Crimson Seedless. Quadrilateral cordon training and spur pruning are suggested. Scarlet Royal berries are susceptible to quality issues if the fruit remains too long on the vine and becomes overripe— therefore a timely harvest is paramount.
For the latest (2023) data on total acreage planted to, average price paid for, and total quantity of this variety produced, see the California Grape Acreage Report, 2023.
A late-season, seedless, white, oval-shaped grape that tends to be larger than Thompson Seedless. This cultivar produces medium-sized, conical to cylindrical-shaped clusters. Autumn King ripens mid-September to late October, or about eight weeks after Thompson Seedless. Autumn King is a vigorous variety and should be head-trained and cane-pruned. Depending on vine vigor and trellis system, 5-8 canes that are 12 to 15 buds long are retained at pruning.
For the latest (2023) data on total acreage planted to, average price paid for, and total quantity of this variety produced, see the California Grape Acreage Report, 2023.
An early-season, white seedless grape with large berries and a slight muscat flavor.
For the latest (2023) data on total acreage planted to, average price paid for, and total quantity of this variety produced, see the California Grape Acreage Report, 2023.
For the complete list of varieties and production in California and by subregion, see USDA’s Grape Acreage Report 2023 (pp. 11).
Addressable Market
Market
Based on the Knowledge Sourcing Intelligence Report, the global table grape market is projected to grow at a CAGR of 7.67% (2022-2027), meaning the global market which was valued at US$62.674 billion in 2020 will reach a total market size of US$104.811 billion in 2027. Increased demand is due to growing awareness of the benefits of consuming fruits especially in critical, high-demand markets like China, India, and Turkey, and technological advancements, such as innovations for better storage, control of decay, and water loss of grapes.
According to a report by Mordor Intelligence, the global table grape market size was valued at approximately USD 18.1 billion in 2020 and is expected to reach USD 24.7 billion by 2026, growing at a CAGR of 5.2% during the forecast period (2021-2026). Knowledge Sourcing Intelligence estimates the global market for table grapes at $67 billion in 2022.
The true addressable market for table grape harvest and management automation technologies will be in large part determined by the cost of labor performed to manage and harvest table grapes. To accurately determine the value of a specific technology to the table grape sector, it’s necessary to understand table grape crop budgets.
Current Challenges and Key Opportunities
Grower Challenges: Production
Successful table grape growers manage a complex production system that takes careful and continuous management over a variety of shifting plant life stages. From the beginning of the vineyard planning process until the first harvest can be anywhere from 3-5 years, and remain productive for approximately 22 years. Managing production and cash flow over that time horizon is often a challenge.
- Table grape vineyards tend to be established on fairly level ground, but may be additionally laser-leveled before planting.
- Before plants arrive, the ground must be chiseled to a depth of 4’-5’ and a pre-plant herbicide should be applied. Fumigation may be necessary if nematodes are present.
- In Spring, the vineyard is laid out and marked, followed by planting vines and placing protective, cardboard cartons around the starts. Vines should be spaces 6’ apart, and 12’ should exist between rows (resulting in 605 vines/acre). Vines that fail to survive can be replanted in the second year.
- Plants are dormant, bench-grafted rootstock. Example prices:
- Flame seedless vines: $3.25/vine, $1,966/acre
- Ivory vines: $7.25/vine or $4,386/acre
- Scarlet Royal vines: $3.25/vine (+ $1/vine royalty to variety owner)
- Autumn King vines: $3.25/vine (+ $1/vine royalty to variety owner)
- After the first year of establishment, a grower will install a trellis system and begin training vines in anticipation of the first yield in the third year after planting.
- Before the second season, a commercial company installs the trellis system, which will be used throughout the life of the vineyard. There are varying styles and systems of trellis systems better suited for different varieties of table grapes and vineyard setups. The most common in California table grapes include:
- Vertical shoot positioning is one of the most common trellis systems. Key features include grapevines trained to grow upright, with cordons (one or two) growing horizontally along a wire. This system provides good air circulation, and sunlight exposure and is relatively easy to manage.
- California sprawl is a trellis system more common for vigorous varieties, like Thompson Seedless. The grapevines are trained to sprawl horizontally, with canes fanned on a low wire (or the ground). This provides good access to the fruiting zone.
- Geneva Double Curtain (GDC) is an increasingly common trellis system for high-yielding varieties like Flame Seedless and Crimson Seedless. Vines are trained along a two-tiered cordon system with vertically divided canopies that are supported by multiple wires. This system is known for promoting good yields and solid fruit quality.
- Other trellis systems include the Open Gable or V-trellis system, which utilizes a V-shaped structure formed by two wires to support vines, and the Modified Lyre, which involves training vines to form a “Y” shape with horizontal canes supported by wires.
- Five training passes are usually made during the spring and summer of the second year. This process involves tying a single shoot to the stake (to begin forming the permanent structure of the vine), removing lateral shoots from the base of the vine, and tipping the shoot when it reaches the top of the stake. This usually marks the first significant labor outlay for the grower.
- Trellis often require regular repairs, and the cost of repairs tends to increase over the life of the vineyard. Weak or missing vines also must be replaced.
- Even more than harvest, pruning is often the most intensive and recurring labor-heavy task in a table grape vineyard— often requiring relative skill and multiple passes through each row to do varying tasks during different times of the year.
- Pruning is a valuable activity because it contributes to new growth for plants and helps prevent the spread of disease.
- Vines are first pruned during the first dormant season (December to February), according to the preference of the grower or the optimal style for the variety.
- Vines are spur-pruned during the winter months.
- Suckers, sterile shoots, and basal leaves are removed from the vine trunks and crowns in late spring, a practice that continues each year after which shoot positioning takes place.
- Finally, this process is followed by hedging, an equipment-assisted process.
- Pruning waste is placed between rows.
- Water cost and usage will vary from grower to grower in key table grape areas in California, depending on the quantity used, power cost, well characteristics, and other factors. Water cost is expected to rise in the San Joaquin Valley in the coming years.
- Table grape vineyards are irrigated (usually via drip irrigation) during the growing season, in California from April through October during established years. The amount of applied irrigation water varies depending on rainfall and other factors.
- Common vineyard drip systems require chemical flushing to prevent chemical buildup.
- If levels of sodium, chloride, or boron in vineyard soils are high, they must be leached from the soil, typically through in-season application of a leaching fraction or through dormant season watering.
- Irrigation levels are reduced after harvest to control vine growth and promote cane maturity. In some years, water may be required in the late winter/early spring to protect against frost.
- Running, monitoring, and maintaining the irrigation system on a vineyard usually requires some amount of labor outlay.
- In late Spring, gibberellic acid (GA), a plant growth regulator, is applied in two different applications during bloom to increase berry size.
- Cluster tipping and hand thinning are done in late May to early June to loosen clusters and adjust cluster length and crop load. Vines are often girdled to increase berry size in early summer.
Table grapes are hand-harvested and field packed, and each field is usually picked 2-3 times, mainly due to the fact that table grapes ripen non-uniformly, meaning harvest on one farm with multiple varieties can last several months. Harvesting crews work in teams of 3 or 4, with each harvester picking 3-4 19-pound boxes per hour (depending on factors including fruit quality).
Harvest
- Harvest workers #1 and #2 cut bunches of grapes (picker/packer pair) and put them in plastic tubs
- Harvest worker #3 and #4 uses a wheelbarrow to transport the full tubs to a packer at the end of the row
- Some harvesting crews use teams of two people, with both workers beginning the day picking and, after six to eight loads of grapes are picked, one worker begins to pack while the other continues to pick.
Packing
- Packers trim bunches on portable tables and place them into the bags or clamshells in which grapes are sold
- Packages are then cooled in packing houses before shipping and can be held in cold storage for at least two months.
- Most table grapes are picked and packed in the field. Some table grapes go to packing houses for this step, especially those that are packed into clamshells. Pickers cut bunches of grapes and place them into picking boxes, which are taken to the packing house to be packed or to cold storage for packing at a later date.
Table Grape Harvest Timing
Month | Event |
May - June | Blooming |
July - August | Thinning |
September - November | Harvesting |
In California, the table grape harvest season ordinarily runs from May to November (starts in Cochella and ends in the San Joaquin Valley)
- The overall size and scale of the farming operation, and what other crops/varieties the farmer grows.
- Whether the land is owned or managed by the grower.
- Infrastructure availability (road access, irrigation systems, building locations, etc.)
Grower Challenges: Economics
Common Table Grape Business Model
Table Grape growers sell grapes to wholesalers, retailers, and other buyers. The success of the business will depend on the yields achieved, the quality of produce, the price, and the distribution networks they are able to access. Additionally, table grape growers must consider other costs such as labor, fertilizer, and pest management, land costs (including land rent if leasing), as well as the potential for unexpected weather or market conditions.
Growers sell table grapes in the US in 19-pound* boxes, which contain approximately 8 individual bags or clamshells of grapes.
There are a few different channels that growers commonly use to deliver grapes to market. The most common is to contract the sale of table grapes, with a price per unit and total quantity determined in advance of harvest. These contracts may be with wholesale produce packers, shippers, or directly with retailers (especially in the case of larger farmers, packing and shipping functions may be carried out by the grower). Alternatively, table grape growers can take (most commonly, excess) table grapes to a terminal market, where they are sold based on a shifting and localized market price in bulk. Finally, table grapes can be sold directly to consumers through on-farm sales, U-pick operations, or farm stands, though a very small amount of the total US table grape crop is moved in this fashion.
The business model for table grape production requires a significant upfront investment that must be earned back over the course of a vineyard’s productive life. Though vines will start producing fruit as early as the second or third year, they often don’t come into their productive prime until their fifth or even seventh year. As the vineyard ages, yield and quality generally decline, and there is an expectation that approximately 1% of plants will need to be replaced annually. After approximately 20-30 years, the vineyard will usually reach the end of its life.
The yield of the average acre of table grape vines can vary significantly based on a number of factors, but for commercial varieties, an expectation of yield between 1,200 and 2,200 boxes per acre is reasonable. Many factors also determine the current price per unit of table grapes, and thus predicting net revenue, or determining in which year the vineyard overall might become profitable, is not possible to generalize.
The price that a table grape producer receives is dependent upon variety, timing, and other market factors. Specific quality standards vary by geography and purchaser.
*Note: Some USDA reports site table grape boxes as 18-pounds, some as 19-pounds. Our experience talking with growers has mostly featured 19-pound boxes, so we used that figure.
Table Grape Crop Budget
We highly recommend that you read two or more crop budgets before having a conversation with a table grape farmer to better understand their needs and costs.
- Crop Enterprise Budget Example #1: San Joaquin Valley | Flame Seedless
- Crop Enterprise Budget Example #2: San Joaquin Valley | Sheegene-21
- Crop Enterprise Budget Example #3: San Joaquin Valley South | Scarlet Royal
- Crop Enterprise Budget Example #4: San Joaquin Valley South | Autumn King
Understand that farm economics and budgets vary widely between individual farm operations, and annually as a result of a landscape of factors, from water availability to input costs.
Table Grape Costs
Though there are many fairly standard expenses on a table grape farm, the magnitude of related costs varies widely based on geography, varieties grown, weather, and many other factors.
- Capital costs include:
- Land (rent or purchase)
- Property alterations (like laser-leveling prior to vineyard construction)
- Irrigation systems (including installation)
- Trellises
- Initial vine plantings
- Production and harvest equipment, facilities, and vehicles
- Variable costs include:
- Water (generally calculated per acre-inch)
- Replacement vines
- Energy and fuel costs
- Equipment/facilities maintenance
- Inputs (including fertilizer, pesticides, and other crop protection, etc.)
- Auditing, compliance, and inspections (often charged either per box/pound or per acre)
- Property taxes
- Insurance
- Labor costs:
- Labor is by far the largest recurring expense on a table grape operation. Workers are necessary to take care of annual pruning and harvesting, and for best results, relatively skilled labor is best.
- In California, the minimum wage for agricultural workers is $15.50 an hour, with additional requirements around overtime and days off. USDA estimates that a representative average of 688 labor hours are required per acre (a combination of pre-season pruning/maintenance and harvest), meaning a table grape farmer can expect to spend at least $10,660/acre on labor costs annually.
- “Based on these estimates, California’s 121,000 acres of table-type grapes required a total of 83 million hours of hand labor in 2019, which is equivalent to 83,000 workers who average 1,000 hours each.”
- Most table grape operations also require some professional labor, including farm manager employees, but also contractors like pest control or crop protection advisors, accountants, and others.
Outside Pressures on Table Grape Businesses
- Lack of available workers for hire, especially during critical and time-sensitive parts of the season often leads to harvest reductions and high-quality table grapes being left in the field.
- Though the industry has generally not depended on the H-2A program to acquire additional workers, this is an option that could be pursued more broadly in the future, though doing so is often a time-consuming and financially costly endeavor for growers.
"The (worker) shortage is real this year, so growers will make a decision to harvest their most profitable varieties," said Ian LeMay, president of the California Fresh Fruit Association trade group. "Ultimately you might see some fruit left in the orchard. That's just a reality." Rick Deckard said it's been hard during the harvest keeping workers on the site, especially when it's "really, super hot.”
Competition from Foreign Markets
- US table grape production increasingly faces competition from Central and Latin American producers, notably Mexico in the early season and Peru in the later season.
- For example, according to the International Fresh Produce Association, in 2021-2022, “Central California volumes of table grapes produced decreased 1.3% or 21.5 million pounds, dropping its market share from 49.4% to 45.3%. Chile’s volume grew 14%, from 721 million pounds to 822 million pounds, increasing its market share from 22% to 23.3%. Peru showed the highest growth at 26.8%, increasing from 501 million pounds to more than 635.5 million pounds. Mexico’s volume grew 9%, from more than 361 million to almost 394 million pounds. Its market share grew by 0.2% due to the growth of the total market.”
Consideration for Harvesting Automation/Mechanization
There is clearly a role for harvest mechanization and/or automation to address multiple challenges in the table grape sector and create opportunities to:
- Increased efficiency: Automated harvesters could potentially pick for longer periods of time and more consistently than manual labor, increasing the overall efficiency of the harvest process.
- Reduced labor costs: Automation solves a critical challenge in the ag labor industry, and allows farms and farmers to fill a gap that already exists between labor we need and labor that is available.
- Improved working conditions: Automated harvesters can reduce the physical strain and repetitive motions associated with manual picking, leading to improved working conditions for employees and potentially reducing the risk of injury.
- Consistent quality: Automated harvesters can pick more consistently than manual labor, leading to improved quality control and a higher-quality product for consumers and an ability to pick on an exact color line (rather than relying on hundreds of different human eyes) AND the potential for in-field defect sorting which might reduce grower costs by increasing take rate by the processor.
- Increased reliability: Automated harvesters can operate 24/7, rain or shine, and are less likely to miss a harvest due to illness or other absences, increasing the reliability of the harvest process.
Technologists designing for key issues in this field should consider the unique features of the industry.
- All automation or mechanization tools will likely require long battery lives, sturdy, rugged construction, and other reliability refinements to deal with dusty field conditions and being used around the clock to travel relatively long distances.
- In most cases, farmers rely on mechanics on-site and do not have access to electronic/robotic engineers.
- Crews often do not speak English fluently, and they may not be able to read or write. Crew members may also not be uniformly able to communicate with each other due to language barriers.
- High-speed internet and high bandwidth cellular services are far from a given in rural areas.
- Vineyard factors including row spacing will vary across vineyards, based on grape variety, trellis system, climate, and preferred management practices. The amount of space between rows affects sunlight penetration, air circulation, canopy management, and equipment access, and thus has implications for vine quality and productivity over the life of the vineyard. Common row spacing in US table grapes varies from 8 to 13 feet.
- Different grape varieties can have highly variable growth habits, vine vigor, and healthy canopy sizes. This can affect everything from row spacing to harvest practices.
- Table grape vineyards, especially in California, tend to rely on a few common types of trellis systems, namely; vertical shoot positioning (VSP), Geneva Double Curtain (GDC), and bilateral cordon systems. Each trellis system will have unique specifications for row spacing, management practices, etc.
- Equipment and labor access are factors that are commonly considered in determining row spacing during the vineyard planning process, however, altering row spacing during the productive life of the vineyard is nearly impossible.
- This paper contains an overall review of the research and developments that have been performed to automate each major activity (e.g., pruning, thinning, spraying, harvesting, and mobile navigating) in the cultivation of pome fruit.
- Due to the softness of grapes, the heterogeneity of grape bunches, and other factors, automation of harvesting itself is extremely difficult.
- However, harvest aids can help improve the productivity of the current workforce and relieve the need to do many of the most physically demanding tasks, including lifting and carrying heavy loads of delicate grapes.
- Existing commercial solutions provide harvest aids that automate the process of moving table grape boxes from an in-field packing station to the end of the row, where boxes are loaded into a transport vehicle for transport to cold storage. These tools complete this action using cameras and sensors, and in carrying out this work replace wheelbarrows and increase worker productivity.
- In a 2020 study, harvest crews working with harvest aid robots packed 14% more boxes than non-robot crews in half rows, 25% more in full rows, and over 40% with a central packing station. Workers also reported less fatigue.
- There are likely more opportunities for improving the harvest process with automation and mechanization.
- In-field table grape harvesting bins (or lug totes) are typically rectangular, plastic, and have open tops and solid or slotted sides and bottoms. Common dimensions are around 23-24 in L x 16-17 in W x 8-9 in H. Stackability (both for storage and when carrying grapes), handleability, and the ability to easily label, track, and sanitize are critical.
- Table grapes that are to be consumed fresh must, immediately after harvest, enter a cold chain to ensure freshness, taste, and appearance as they travel from the vine to consumer’s tables.
- This process starts with pre-cooling, where temperatures are rapidly brought to around 0-4°C or 32-39°F, and then remain within that range as an optimal storage temperature range. This cooling is achieved through forced-air cooling or hydro cooling in the minutes after the grapes are removed from the vine.
- Maintaining proper humidity levels is also key during the storage process, typically at around 90-95%. This is also a key function of breathable packaging like clamshell containers or vented bags, which improve ventilation, promoting proper air circulation so grapes neither dry out nor wilt due to excess moisture.
- It is critical to minimize the handling and movement of grapes between chilled places during the packing and shipping process to maintain the highest quality in the final product that arrives on retail shelves.
- Key quality concerns, including; decay, shriveling/wrinkling, berry splitting, berry drop, browning, stem browning, and off-flavors are common among table grapes and can impact the salability and value. Some of these issues are caused by in-field and production issues, while others are caused (or worsened) by poor handling practices.
- Pruning and thinning tasks are more standardized and less risky than harvesting tasks, and therefore a better target for automation and mechanization innovation.
- Machine vision will likely be a critical component of these types of innovations, which could also extend into crop protection spraying of weeds and other pests at the in-field level.
- Mechanical pruning equipment is most commonly used to “pre-prune” vines, a task which is then followed up with hand pruning to ensure the appropriate amount of buds is present on each vine. When pressed for labor, however, farmers may use a pre-prune machine with no follow-up.
- Leaf-removal or canopy-thinning equipment has also become common, as newer systems do a better job removing leaves while causing low levels of damage to clusters.
- At some times, crop control is also a key pruning function, which can also be done mechanically using existing equipment, or through manual or chemical means. Crop control involves thinning either flowers or grape bunches themselves, in other words, removing over-cropped bunches to ensure that the remaining fruit maintains quality.
- Other equipment is available to carry out vineyard tasks such as suckering and moving wires during shoot positioning.
Consideration for Pests and Disease
Table grape production is susceptible to a range of pests and diseases that can impact grape quality and yield. Some of the most common pests and diseases in table grape production include:
- Powdery Mildew: A fungal disease that can cause a powdery white coating on the leaves and fruit of grapevines, reducing the quality of fruit in addition to reduced photosynthetic efficiency of the plant and increased fruit susceptibility to rot. Early in the vineyard’s operation, plants should be treated with a fungicide for both powdery mildew and Phomopsis at least annually. Effects can be similar to but not the same as downy mildew: a fungal disease that can cause yellow spots on the leaves of grapevines and can lead to stunted growth and reduced fruit quality.
- Phomopsis Cane and Leafspot: This disease manifests as dark spots with yellow margins on leaf blades and veins in the weeks following rain. The disease can affect leaves, berries, canes, and cordons, and significantly hamper the productivity of a vineyard. The disease spreads from currently infected plants to others during rains when free moisture transits disease spores. Chemical treatment is usually necessary.
- Botrytis Bunch Rot: This fungus can cause early-season shoot blight following prolonged warm moist conditions, leaving patches of soft brown tissue and eventually killing infected plant parts. Infected berries eventually develop a characteristic gray, fuzzy mold. High moisture and moderate to warm temperatures lead to the worst infections. Berries that have been damaged by insects, birds, machinery, etc. may become infected at any time after the fruit begins to ripen because the juice in the berry can provide the necessary water and nutrients for fungal growth. To avoid Botrytis, vineyard design is critical. Balanced canopies with moderate shoot vigor that optimizes leaf and cluster exposure can reduce the conditions that promote Botrytis. Shoot thinning, hedging, and leaf removal are also used to manage canopy density.
- Black Root Rot: A fungal disease that can cause brown or black spots on grape leaves and fruit, leading to crop losses from 5 - 80%, and in extreme cases can destroy an entire crop. Black root rot overwinters in mummified fruit on the vineyard floor or in old clusters on vines, and reinfect living plants during spring rains. Temperature and length of time leaves are wet effect infection. Resistant varieties are available to avoid the disease.
- Vine Mealybug: Small, oval-shaped insects that exude a white, mealy wax. The insects themselves can damage grape clusters, leaving them inedible, and the waxy exudate that they emit can cover fruit and leaves, creating an apt environment for other diseases to infiltrate. Vine mealybugs are unable to fly and are often transmitted from infested areas to un-infested vineyards by humans and equipment, especially equipment that pushes brush or any over-the-row equipment.
- Pacific Spider Mite: A tiny, web-spinning insect that is often first identified by the yellow damage spots it creates. As damage spreads, leaves can begin to die and the productivity of the whole plant is affected. Reducing dust levels in the vineyard as well as plant stress can reduce the incidence of mite infestations. Mite and mealybug populations must be monitored weekly during the key production season (spring to fall), creating additional labor expenses.
- Grapevine Leafhopper: A key pest in the San Joaquin Valley, this yellow-brown insect can cause significant damage to grapevines when their populations are too high, by feeding on the leaves, causing them to yellow and drop prematurely. Though grape plants can go unaffected by some amount of leafhopper activity, reducing populations is sometimes necessary. This can be done chemically or through a more rigorous pruning process.
- Various weeds can pose challenges to vineyard production when growing on the vineyard floor, but machine or hand applications of pesticides combined with preventative discing, mowing, and occasional hand weeding are usually effective to keep weeds at bay.
- Small mammals like gophers and squirrels can also cause damage in the vineyard and may require baiting, trapping, or constructing fencing to exclude.
Consideration for Climate Change
Climate Change and Weather Impacting Table Grape Production
Climate change and weather are having a significant impact on table grape production both domestically and globally, though the exact nature of these impacts in any specific region is difficult to accurately predict.
- Shifts in Growing Seasons and Regions - changing patterns of heat and precipitation are likely to cause shifts in both growing seasons and growing regions for table grapes. Temperature is a key determinant of phenological stages like bud break, flowering, and harvest, so as temperatures change, growers will need to adjust their management practices, including irrigation schedules and canopy management. Current grape growers may be able to offset some of these changes by modifying existing vineyards.
- Heat Stress and Sunburn - Heatwaves and higher temperatures associated with climate change can increase the risk of heat stress and sunburn in table grapes. High temperatures during the growing season can affect fruit development, leading to reduced yields and compromised fruit quality. Growers may need to implement strategies such as shade systems, misting, or modified trellis designs to mitigate heat stress and sunburn risks.
- Water Availability - Climate change can influence water availability, with some regions experiencing more frequent and severe droughts or changes in precipitation patterns. Water scarcity can impact table grape production, particularly if irrigation supplies become limited. Improved water management practices, such as efficient irrigation systems and water conservation measures, may become even more critical.
- Pest and Disease - Climate change can influence the distribution and abundance of pests and diseases that affect table grapes. Changes in temperature and humidity levels can impact the prevalence and geographic range of pests and diseases, potentially leading to new or increased pest pressure. Growers may need to adapt their pest management strategies and be vigilant for emerging threats.
California Table Grape Commission President and CEO Kim Nave was quoted in Farm Progress in 2023 on the subject of reduced table grape production,
“There was frost in late April. There was high heat. There were strong winds. There was rain. And there was a combination of rain and high heat which causes humidity. Throughout the season, primarily in San Joaquin Valley but also in the Coachella Valley, both areas were impacted by weather conditions. Weather is always a factor that can leave a percentage of the crop with lessened quality that growers don’t want to put in a box. But this year was tougher than most because there were more frequent and adverse weather effects that lasted longer.”
Grape growers have also been very hard by the hurricane and related storms.