California produces almonds worth $5.3 billion every year. That is 100% of commercial almonds in the United States, and 100% of all of North America, and 80% of commercial almonds around the world.
Agriculture is a significant sector in California's economy, producing nearly $50 billion in revenue in 2018. There are more than 400 commodity crops grown across California, including a significant portion of all fruits, vegetables, and nuts for the United States.[1] In 2017, there were 77,100 unique farms and ranches in the state, operating across 25.3 million acres (102,000 square kilometres) of land. The average farm size was 328 acres (133 ha), significantly less than the average farm size in the U.S. of 444 acres (180 ha).[1]
Because of its scale, and the naturally arid climate, the agricultural sector uses about 40% of California's water consumption.[2] The agricultural sector is also connected to other negative environmental and the health impacts, including being one of the principle sources of water pollution.
The table below shows the top 21 commodities, by dollar value, produced in California in 2017.[1] Between 2016 and 2017, there were increases by more than 2% in total value for the following crops: almonds, dairy, grapes and cattle. The largest increase was seen in almond sales, which increased by 10.9% from 2016 to 2017, due to both increases in crop volume produced and the average market price for a pound of almonds. Dairy sales increased 8.2% from 2016 to 2017 due to an increase in the average price for milk, despite a slight decrease in total milk production. Grape sales increased by 3.1% from 2016 to 2017 due to an increase in price per ton of grape (from $832 per short ton ($917/t) in 2016 to $847 per short ton ($934/t) in 2017). Cattle sales also increased by 2.7% from 2016 to 2017.[3][4]
California produces 80% of the world's almonds and 100% of the United States commercial supply.[5] Although almonds are not native to California, a hot, dry Mediterranean climate and developed water infrastructure create favorable conditions for commercial cultivation of the crop.[6] In 2020, there were 1.25 million acres (5,100 km2) devoted to almond farming in California, producing 2.8 billion pounds (1.3 Mt).[7]
Almonds are the state's most valuable export crop.[5] Farmers exported $4.9 billion worth to foreign countries in 2019, about 22% of the state's total agricultural exports, with the European Union, China and India as leading destinations.[5]
California almond farms import the majority of US commercial bee colonies to the state of California during the almond pollination season. Almond production in California is the source of several major environmental problems, including high demand for water and abundant waste of almond shells. As of 2021, due to a historic long-term drought in California, production was forecast to decline, and many almond orchards were being abandoned.[8]
Shipping disruptions, reductions in consumer spending, and trade disputes during 2020-21 caused by the COVID-19 pandemic affected logistics and pricing of almonds.[7]
Avocados
California farms produce 90% of all U.S.-grown avocados, with the great majority being of the Hass variety.[9] In 2021[10] the state harvest was 135,500 short tons (122,900 t) on 46,700 acres (18,900 ha) for a yield of 2.9 short tons per acre (6.5 t/ha), and at $2,430 per short ton ($2,679/t) that brought $327,369,000. Drought and heat can significantly reduce the harvest in some years.[11] The Polyphagous Shothole Borer and the associated disease it carries have been a great concern here since their discovery on home avocado trees in LA County in 2012.[12] Immediately eradication and quaratine efforts were instituted, and are continuing.[12] (See § Polyphagous shot hole borer below.)
Almost all of the country's broccoli is grown here.[14] In 2021[update] that was 11,200 planted acres (4,500 ha), all of which was harvested.[14] The yield was 130.0 short hundredweight per acre (14,570 kg/ha; 13,000 lb/acre) for a harvest of 1,512,000 short hundredweight (68,600 t; 75,600 short tons).[14] There was only trace wasteage.[14] Selling at a price of $51.50 per short hundredweight ($0.5150/lb; $1.135/kg), the year sold for $631,455,000.[14]
For a common disease of erect and trailing caneberry (excluding raspberry), see § Leaf Spot of Caneberry.
Cannabis
Cannabis is estimated to be the largest cash crop in California with a value of more than $11 billion.[18] The state provided most of the cannabis consumed in the United States prior to legalization which was intended to provide a transition to legal, licensed growing. The California Environmental Quality Act (CEQA) requires a detailed analysis of the environmental impact of growers operations. Statewide, 208 growers had obtained regular, annual licenses by July 2019. At this point of some 18 months into legalization, 1,532 growers were still operating on provisional permits as they went through the CEQA process that requires extensive paperwork.[19] Smaller farms were given five years to become established under legalization before larger growers were allowed to enter the market.[20] Under the regulations set to expire in 2023, growers can have only one medium licence but there is no limit on the number of small licenses an individual grower can have. This loophole has allowed larger growers to operate.[21]
Humboldt, Mendocino, and Trinity counties have long been known as Northern California's Emerald Triangle as it is estimated that 60 percent or more of all cannabis consumed in the United States is grown there. Registering and applying for permits has not been an easy decision for many long time growers in these three counties.[18]
In Santa Barbara County, cannabis growing has taken over greenhouses that formerly grew flowers. In the first four months of legalization, the county had almost 800 permits issued for cultivators, the most of any county in the state.[21]
Calaveras County registered more than seven hundred cultivators after county voters approved a tax in 2016.[22]
Cherries
The California Cherry Board[23] is a state marketing order representing growers and intermediaries here.[24] The USDA FAS's Market Access Program funds international advertising especially in Canada, South Korea, Japan, China, and Australia.[24] The state produces the earliest crop in the year[24] starting in mid-April.[25] Lasting until early or mid-June every year, this is the second heaviest harvest after Washington.[25]
The center of the state produces almost all the entire crop[27] and San Joaquin County, near Lodi is the highest producing county.[25] Many of these are Bing.[25] As of 2022[update] newer Bing strains with better heat tolerance have recently been planted here as well as counties further south.[25]
From 1997–2000,[34] the state's acreage varied between 10,500–11,000 acres (4,200–4,500 ha) bringing in $57,969,000–$67,744,000. By 2021[10] however the harvest was down to 1,038,500 short hundredweight (47,110 t; 51,920 short tons) from 6,700 acres (2,700 ha) for a yield of 155 short hundredweight per acre (17.4 t/ha; 7.8 short ton/acre), and at $23.2 per short hundredweight ($510/t; $464/short ton) that brought only $24,043,000.
Dairy
Dairy is a significant part of the agricultural output of the state of California. California ranks first out of the fifty states in dairy production. The state has about 1,300 dairy farms and 1.727 million dairy cows.[35] The state produces nearly 20 percent of all U.S. milk.[36]
Dates
Over 90% of US production is grown here, and most of that in the Coachella Valley.[37] The distant second is Arizona.[37] The 2020 harvest was 49,300 short tons (44,700 t) from 12,500 acres (5,100 ha), for a yield of 3.94 short tons per acre (8.8 t/ha).[37] The year's crop sold for $114 million, an average of $2,320 per short ton ($2,557/t).[37] The harvest extends from the beginning of October to the middle of December.[38]
The detection of the red palm weevil (Rhynchophorus ferrugineus) in 2010 was very concerning to this valuable industry.[39] A tremendous effort was made to trap and eradicate, and the last sighting was on January 18, 2012. Three years later on January 20, 2015, USDA's APHIS declared the eradication successful.[39] Its relative the South American palm weevil (R. palmarum) has killed increasing numbers of Canary Island date palms (Phoenix canariensis) and is expected to become a significant pest of dates in the future.[39]
Relative to traditional farming, aquaculture is a small part of California's agricultural economy, generating only $175 million in 2014.[42] Oysters, abalone, mussels, channel catfish, rainbow trout, and salmon are farmed commercially.[43]
Stripe rust is a continuous presence in the state.[13] It is believed to have arrived at or before the 1770s because newspapers reported it starting then, and because there is a greater presence today of stripe than leaf or stem.[13]: 3 See § Stripe rust.
Grapes
The 2020 table grape harvest was worth $2.12 billion[44] while wine grapes brought in $1.7 billion, down 15.3% year-on-year. By weight this was 17% lower versus 2018.[45] The next year, 2021[10] saw a much better yield. From 829,000 acres (335,000 ha) viniculturists got 6.94 short tons per acre (15.6 t/ha) for a total harvest of 5,755,000 short tons (5,221,000 t).[10] At an average of $909 per short ton ($1,002/t) they were paid $5,229,902,000 for the season.[10] Of that, 4,844,600 short tons (4,394,900 t) were for destined for processing industries (including wine, see § Wine below) and at $835 per short ton ($920/t) that was worth $4,046,382,000.[10] The fresh (table grape) harvest was 910,400 short tons (825,900 t) and selling at a price of $1,300 per short ton ($1,433/t), this sector was worth $1,183,520,000 for the season.[10]
The seriousness of powdery mildew (Uncinula necator) has been recognized since at least 1859 in the northern grape district.[45] The same Pierce was working in the area a few decades before his discovery of PD, and over the 1860s he watched U.necator spread to the south.[45] Frederic Bioletti called it the only serious fungal disease the industry suffered from, and so it has remained ever since.[45][49]
UCD's FPS performs disease testing, vinestock identification testing, and supplies vinestock.[50][52] FPS is one of the few National Clean Plant Network (NCPN) holding vinestock for grapes in the country.[50] See also § Foundation Plant Services.
California is the country's largest grower of peaches, producing about 70% of the total.[70]
The California Freestone Peach Association (CFPA)[71] and California Canning Peach Association/California Cling Peach Board (CCPA)[71][72] represent the industry.[73] (Although the CFPA is a separate incorporation, it has always been operated by the CCPA's staff.) The overwhelming majority of the country's peaches are grown here, in 2020[update] 468,000 short tons (425,000 t) for sales of $308.3 million.[74] Since 1980 the total value of the harvest has been slightly increasing.[74] The acreage (hectares) planted in peach has been declining however, down to 73,000 acres (30,000 ha) as of 2020[update].[74]
As of 2021[update]cling deliveries for processing purposes have been on a downward trend for years.[75] From 430,000 short tons (390,000 t) in 2010, delivered tonnage declined to 225,000 short tons (204,000 t) in 2021.[75] Cling yield shows no clear trend over the same time, bouncing between 18.1 short tons per acre (41 t/ha) and 15.3 short tons per acre (34 t/ha).[75]
Prices have been trending mostly upward, from $317 per short ton ($349/t) in 2012 to $518 per short ton ($571/t).[75]
CCPA expects 2022 deliveries to be between 214,200–232,400 short tons (194,300–210,800 t) from a yield of 15.3–16.6 short tons per acre (34–37 t/ha).[75]
Breeding of peach
UCD hosts one of the major breeding programs in the country.[76] Most of the private breeding programs for peach in the country are found in California, with a significant amount of the public breeding also being performed here but also elsewhere in the country.[76]
Cultivation is heavily pesticide-dependent.[88] In the 1970s that put growers on the "pesticide treadmill" – increasing control costs, resistance, and resurgence of previously controlled adversaries.[88]
In pomegranate (Punica granatum), Black Heart (or "Heart Rot") is one of the most common diseases, as it is around the world.[30]: 192 See § Black Heart.
Raspberry
Over 80% of US raspberries (Rubus spp.) are grown here.[94] The country's consumption has increased eightfold between 2001 and 2021.[94] This crop is 15% of the state's fresh berry sales.[94] Acreage (number of hectares) before 2014 is unknown, but in that year 6,800 acres (2,800 ha) produced 1.4 million short hundredweight (64,000 t; 70,000 short tons) selling for $434 million, then the next year 9,700 acres (3,900 ha) produced 2 million short hundredweight (91,000 t; 100,000 short tons) worth $547 million, and in 2016 9,700 acres (3,900 ha) produced 2.1 million short hundredweight (95,000 metric tons; 100,000 short tons) for $358 million, worth more than the peach harvest and four times the pear harvest.[94] The state has the opportunity to capture much of the market because as of 2021[update] most of the raspberry (55%), blackberry, and blueberry market in the country is imported, with Mexico supplying 98% of imported raspberry and they have probably reached their limit.[94] California produces the most fresh market red raspberries, while Washington is highest for the processed market.[94] Because the recent expansion has taken acres that had been pasture, pest and disease pressure is very small – making organic an easy option.[94] The available acreage for that kind of conversion may have reached the limit as of 2021[update] however.[94] Pre-transplant soil fumigation is necessary in conventional, making organic inviable if this kind of new(-to caneberry) acreage is not available.[94]Driscoll's is the marketer of 90% of raspberries from California and Mexico sold into the US.[94]
By 2006, California produced the second-largest rice crop in the United States,[95] after Arkansas, with production concentrated in six counties north of Sacramento.[96]
California's production is dominated by short- and medium-grain japonica varieties, including cultivars developed for the local climate such as Calrose, which makes up as much as 85% of the state's crop.[97]
So much of North America's stonefruit is grown here that almost all available propagation material is adapted to California specifically.[100] Few accessions are available which are appropriate anywhere else.[100] Even so these are really made for the previous situation in the state, in which lower densities prevailed and dwarfing rootstocks were not used.[100] With increasing mechanization there is a need for such rootstocks.[100]
Strawberries (Fragaria × ananassa) in the United States are almost entirely grown in California – 90% – with Florida a distant second.[101][102]
The California Strawberry Commission (the Board's new name) is the Agriculture Department body which advocates for strawberry growers. The CSC provides information for both growers[103] and consumers.[101] Some towns have annual strawberry festivals, see Strawberry festival § United States. The Driscoll's company began with strawberries here and still grows and sells here, and they have since expanded to other states, countries, and types of berries.
Cal Poly runs the Strawberry Center[104] for both research, and producer education.
As of 2022[update] there is increasing interest and increasing progress in automated (robotic) phytopathology in this crop, especially monitoring for insects and UV-C application for mites.[107]
The use of soil fumigation was highly praised and widely recommended by the California Strawberry Advisory Board in 1967.[108] Strawberry production here has been highly productive ever since but also highly dependent on fumigants.[109] So vital was the most common fumigant – methyl bromide – that the ongoing phase out of MB has sent growers and researchers scrambling for alternatives.[108] (See § Methyl bromide.) One alternative specifically for nematodes is 1,3-Dichloropropene, however some of the finely textured soils in some of the state's soil regions reduce its efficacy, and as of 2010[update] there are restrictions in some townships on maximum rates.[108] Soil solarization is another option.[69] Stapleton et al., 2005 eliminate almost 100% of annual weeds in this crop with solarization alone.[69] It completely fails against yellow nutsedge however.[69] (See § Soil solarization.)
The only effective treatment of Fusarium Wilt may be genetic resistance.[113] Pincot et al., 2018 tested UCD varieties for resistance and located Fw1, a dominant gene explaining almost all FW resistance.[113]Fw1 is very likely to be a toll/interleukin-1 receptor (TIR) nucleotide-binding leucine-rich repeat (NB-LRR) gene.[113] They also identify seven accessions which are fw1 (recessive susceptible homozygous) yet nonetheless resistant, and thus predicted to carry yet-unidentified novel genetics.[113] See § Fusarium Wilt of Strawberry.
Insects are a constant concern.[114][115] The Beet Armyworm (BAW, Spodoptera frugiperda) skeletonizes leaves, damages crowns, and then begins eating the berries.[115] BAW is especially a problem of the southern and Santa Maria strawberry zones, but can damage transplant crowns anywhere in the state.[115] Egg deposition is most often in the fall.[115] Overwintering is possible and will produce earlier and more severe infestations.[115] BAW is controlled by a parasitoid wasp, Hyposoter exiguae, and by Spodoptera exigua nuclear polyhedrosis virus (SeNPV)[64] but additional control may be needed.[115]Insecticides during transplanting are needed sometimes in the southern areas, but sometimes not due to natural controls.[115] A good part of control relies only on weed management in the surrounding area, depriving BAW of alternate hosts.[115] Further control may be needed using insecticides including methoxyfenozide, spinetoram, Bacillus thuringiensis ssp. kurstaki, diazinon.[115]Organic control requires all of the non-insecticide methods (aggressive weeding, wasps, virus) plus Bacillus thuringiensis ssp. aizawai or Entrust which contains spinosad.[115]
Birds have mixed effects on strawberries here.[116] They both eat farmed fruits but also the insects that trouble them.[116]Hedgerows attract birds, whether that is desirable or undesirable.[116] In the Central Valley, farm hedgerows, treelines, and woodlands will have 2x–3x the number of species and 3x–6x the population size of birds than an unvegetated edge of a field.[116]
Whatever the specific effect of birds upon strawberry fields, large hedgerows in this state do improve both the yield and quality of strawberries grown nearby versus those grown next to smaller hedges or grassy banks.[116]
Beach Strawberry (Fragaria chiloensis), a wild parent contributing to the modern strawberry's genetics
The Davis campus is a major hub of strawberry breeding in the state, and indeed in the world.[119] The Knapp group[120] is a large part of strawberry biology study at the university, including the breeding program – of which Knapp himself is the director.[120] UCD's varieties may be licensed from ITC.[121] From 1986 Douglas Shaw headed the program, and starting in 1991 Kirk Larson co-headed with him.[122] In 2013 they attempted to negotiate a retirement arrangement in which they would start their own breeding company, licensing UCD's patented varieties.[122] UCD initially agreed but, anticipating the loss of revenue from what would essentially be a spin-off, reversed themselves.[122] Shaw and Larson retired anyway in 2014 as California Berry Cultivars, licensed what they could and began to breed from those, and sued UCD for not holding to the previous agreement.[122] UCD countersued, alleging they had walked away with (stolen) unreleased germplasm and various other intellectual property violations.[122] A civil trial resulted and, although CBC rapidly lost ground, the judge suggested that UCD would also be examined and face some consequences if the trial were to proceed.[122] UCD and CBC settled with CBC forgoing $2.5 million in future royalties.[122]
Other strawberry species (Fragaria spp.) are commonly used in breeding, including F. vesca the Woodland Strawberry.[123] The UCD program is no exception and its genetic analyses also are used around the world by geneticists, other researchers, and breeders.[123]
The analysis of Pincot et al., 2018 incidentally identifies a likely bottleneck in UCD's germplasm beginning in 1975.[113]
CalPoly Strawberry Center[104] does not operate a breeding program of its own. Instead the SC screens the varieties that come out of all of the state's breeding programs for disease resistance.[124]
UC Davis's Innovation and Technology Commercialization office licenses and sub-licenses[127] all cultivars created by the entire University system.[128] These are:
As of July 2022[update] twelve nurseries are licensed to propagate UCD varieties: Cal, Cedar Point, Crown, Innovative Organic, Jacobsen Pacific, Larse, Lassen Canyon, Monte Vista, Mountain Valley, NorCal, Planasa, and Sierra-Cascade.[129]
cv. 'Camino Real' produces heavily in the Central Coast.[130] 'CR' yields over 4,000 pounds per acre (4.5 t/ha) more than cv. 'Chandler', and berries average 27 grams vs. 21 grams, in Fresno County.[131]
California walnuts account for nearly all the walnuts grown in the United States. In 2017, walnut production was the seventh most valuable agricultural commodity in California, valued at $1.59 billion in cash receipts.[135]
Wheat
Wheat stripe rust is believed to have been present at or before the 1770s due to newspaper reports to that effect from the time, and due to the greater prevalence of stripe than leaf or stem.[13]: 3 Hungerford (1923) and Hungerford & Owens (1923) found stripe on wheat here and almost all other western states.[13]: 9 See § Stripe rust.
Its contemporary wine production grew steadily since the end of Prohibition, but mostly known for its sweetport-style and jug wine products. As the market favored French brands, California's table wine business grew modestly,[138] but quickly gained international prominence at the Paris Wine Tasting of 1976, when renown French oenophiles, in a blind tasting, ranked the California wines higher than the primer French labels in the Chardonnay (white) and Cabernet Sauvignon (red) categories.[139] The result caused a ‘shock' in viticulture industry since France was regarded as foremost producer of the world's finest table wines. This revolutionary event attributed to expanding the recognition and prestige of vintners in the New World, specifically, the Golden State.[140]
The state produces about ninety percent of the American wine supply and is the fourth largest wine producer among the world's independent nations.[141][142] California has more than 4,200 wineries ranging from home-grown and small boutiques to large corporations with international distribution, and even more vineyards and growers, at close to 6,000.[141][143]
Livestock
Fowl
The domestic fowl industry suffers from avian malaria.[144][145]Chickens (Gallus gallus/G. domesticus) and ducks (Anas platyrhynchos domesticus) are commonly infected, as well as various wild birds.[144] Testing has been done since the Herman group made the first reports of P. relictum infection, in Herman 1951, Herman et al., 1954, and Reeves et al., 1954.[144] (See § Avian malaria and § Plasmodium relictum for the parasite and vectors, and for testing.)
The Central Valley of California is one of the world's most productive agricultural regions.[146] More than 230 crops are grown there.[146] On less than one percent of the total farmland in the United States, the Central Valley produces eight percent of the nation's agricultural output by value: US$43.5 billion in 2013.[147] The top four counties in agricultural sales (2007 data) in the U.S. are in California's Central Valley: Fresno ($3.731 billion), Tulare ($3.335 billion), Kern ($3.204 billion), and Merced ($2.330 billion).[148][149]
Its agricultural productivity relies on irrigation both from surface water diversions and from groundwater pumping (wells). About one-sixth of the irrigated land in the U.S. is in the Central Valley.[150]Central Valley groundwater pollution is an ongoing environmental issue in the area.
There are 6,000 almond growers who produced more than 1.8 million tonnes in 2013, about 60 percent of the world's supply.[151][152]
Parts of the Valley are quarantine as of July 2022[update] due to an ongoing pest eradication.[153][154] The Peach Fruit Fly was found in Chowchilla and this is a threat not only here, but could spread to the entire state, and to a lesser degree the entire country and other locations around the world.[153][154] See § Peach Fruit Fly.
The Salinas Valley, located within Monterey County, is one of the most productive agricultural regions in California. Monterey County grows over 50% of the national production for leaf lettuce, head lettuce, and celery. It also produces significant percentages of the country's broccoli, spinach, cauliflower, and strawberries.[155] The area is also a significant producer of organic produce, with 68,868 acres in cultivation and annual sales of $412,347,000.
California has more certified organic farms than any other state. In 2016, more than a million acres in the state were certified organic.[156] CA grows 90% or more of the U.S. production of Organic almonds, artichokes, avocados, broccoli, cauliflower, celery, dates, figs, grapes, strawberries, lemons, lettuce, plums, and walnuts.[157]
There are two primary laws that regulate organic production: at a federal level, the Organic Foods Production Act of 1990 and at a state level, the California Organic Food and Farming Act of 2016. Both laws lay out standards for production, processing, handling and retailing that must be followed in order to label a product as "organic". The USDA, California Organic Products Advisory Committee, and the California County Agricultural Commissioners monitor and ensure these standards are followed by administering enforcement actions for any violations.[158]
Any agricultural operation selling more than $5,000 in products per year is required to acquire organic certification, if they seek to sell their products under the organic label. Multiple organizations are accredited to certify operations organic.[159]
Environmental and natural resources
Water use
The largest overall water users in California are the environment, agriculture and urban/ municipal uses.[2] In an average year, about 40% of California's water consumption, or approximately 34.1 million acre-foot (4.21×1010 cubic metres), is used for agricultural purposes. However, the exact proportion of total water usage for agriculture can vary widely between 'wet' and 'dry' years, where in wet years, agriculture is responsible for closer to 30% of total water consumption and in dry years, agriculture is responsible for closer to 60% of total water consumption.[2] Water for agriculture is used to irrigate more than 9 million acres (36,000 square kilometres) of cropland annually.[160]
Water for agriculture comes from two primary sources: surface water and groundwater. Surface waters include natural lakes, rivers, and streams, as well as large network of human-built reservoirs and a complex distribution system of aqueducts and canals that carry water from the location of the source to the agricultural users.[160] Groundwater aquifers range in depth and accessibility across the state, and historically have been used to supplement surface water supplies in dry years.[161]
California is one of the top five states in water use for livestock. Water withdrawals for livestock use in California were 101–250 million US gallons (380,000,000–950,000,000 l)/day in 2010.[162]
Water quality
Agricultural impacts on water quality concentrate around concerns of the following contaminants: nutrients, pesticides, salts, pollutants, sediment, pathogens, and heavy metals.[163] These contaminants enter water bodies through above-ground surface runoff of rainwater or excess irrigation water, or percolating through the soil and leaching into groundwater. Water quality concerns affect most regions of the state and tend to be exacerbated during periods of drought.[164]
At present, all irrigated agricultural operations in the State are required to participate in the Irrigated Lands Regulatory Program.[165] The regulatory program began after the California Legislature passed Senate Bill 390 (SB390) in 1990, that eliminated a blanket waiver for agricultural operations to discharge wastewater without any specific environmental standards.[166]
Water supply
A major source for Southern California's water supply, both agricultural and urban, is the Colorado River from which an aqueduct has been built to transport the water from the river to Riverside.[167] Another aspect of the agricultural water supply in California is the transfer of water that takes place from northern to southern California. In northern California, the Shasta Dam contains the flow of the Sacramento River, preserving water for California's use, and pumping stations in the California Delta extract water transferring that water across the San Joaquin Valley and southward.[168] A key component to the distribution of the water supply are the irrigation districts and water agencies who are responsible for delegating water as to meet the demand of those within the area as well as clarify and legal arbitration as to water rights.[169]
The agency tasked with overseeing the state's water supply and any projects associated with the upkeep of the supply is the California Department of Water Resources (CDWR).[170] As part of the 2019-2020 California Spending Plan, the CDWR received $2.336 billion with $833 million going towards projects overseen by the California Natural Resources Agency and $1.503 billion going towards the control board supervised by the California Environmental Protection Agency.[171] One of the CDWR's major projects is the State Water Project (SWP) which distributes 34% of the water that flows through its various channels.[172] The SWP also is one of the largest suppliers of hydroelectric power in the state.[172]
The invasive quagga- and zebra-mussels reached the state in about 2006 and threaten the already limited supply of farm water.[173] The mussels have continued to spread and present an ever-expanding threat to pipelines.[174]
History
Pre-1850
Prior to the arrival of Europeans, the Indigenous peoples of California, with diverse societies mainly reliant on hunter-gatherer methods, practiced seed collection and forest gardening. Some California hunter-gatherer tribes, including the Owens Valley Paiute, developed irrigation.[175]
In the late 1700s, Franciscan missionaries established Spanish missions in California. Like earlier Spanish missions established in Baja California, these missions were surrounded by agricultural land, growing crops from Europe and the Americas, and raising animals originating from Europe. Indigenous workers from Baja California made up a large part of the initial labor force on California missions.[176] In the early 1800s, this flow of laborers from Baja California had largely stopped, and the missions relied on converts from local tribes. By 1806, over 20,000 Mission Indians were "attached" to the California missions. As missions were expected to become largely self-sufficient, farming was a critically important Mission industry.
George Vancouver visited Mission San Buenaventura in 1793 and noted the wide variety of crops grown: apples, pears, plums, figs, oranges, grapes, peaches, pomegranates, plantain, banana, coconut, sugar cane, indigo, various herbs, and prickly pear.[177]
Livestock was raised for meat, wool, leather, and tallow, and for cultivating the land. In 1832, at the height of their prosperity, the missions collectively owned over 150,000 cattle and over 120,000 sheep. They also raised horses, goats, and pigs.[178]
While the Spanish were the most successful farmers active in California in the early 1800s, they were not the only ones. In 1812, the Russians established Fort Ross in what is now Sonoma County, California, and intended the fort in part as an agricultural supply point for other Russian activity on the west coast. Despite Russian plans for the colony, agriculture at Fort Ross had low yields, significantly lower than the California missions. Inefficient farming methods, labour shortages, coastal fog, and rodents all contributed to limit agriculture at the fort.[179]
The Spanish (1784–1810) and Mexican (1819–1846) governments made a large number of land grants to private individuals from 1785 to 1846. These ranchos included land taken from the missions following government-imposed secularization in 1833, after which the missions' productivity declined significantly. The ranchos were focused on cattle, and hides and tallow were their main products. There was no market for large quantities of beef (before refrigeration and railroads) until the California Gold Rush.
1850–1900
In 1848, before the Gold Rush, the population of CA was approximately 15,000, not counting Native Americans. By 1852, there were over 250,000 people in the state.[180] and by 1870, 560,000 people.[181] This rapid population growth drove an increase in importation of agricultural products, and, within a few years, a massive growth in in-state agriculture. In the first years of the gold rush, the state relied on agricultural imports arriving by ship, from Australia, Chile, and Hawaii. During these years, there was rapid growth in vegetable farming for local markets. This was followed by an expansion of grain farming.[180] A shift in the economic dominance of grain farming over cattle raising was marked by the passage of the California "No-Fence Law" of 1874. This repealed the Trespass Act of 1850, which had required farmers to protect their planted fields from free-ranging cattle. The repeal of the Trespass Act required that ranchers fence stock in, rather than farmers fencing cattle out. The ranchers were faced with either the high expense of fencing large grazing tracts or selling their cattle at ruinous prices.[182][183] By the 1890s, California was 2nd in US wheat production, producing over one million tons of wheat per year,[180] but monocrop wheat farming had depleted the soil in some areas resulting in reduced crops.[184]
Irrigation was almost nonexistent in California in 1850, but by 1899, 12 percent of the state's improved farmland was irrigated.[184]
Luther Burbank moved to Santa Rosa, California in 1875, and developed numerous commercially successful varieties of plants over the next 50 years.
1900–1950
The 1902 Newlands Reclamation Act funded irrigation projects on arid lands in 20 states including California.
In 1905, the California legislature passed the University Farm Bill, which called for the establishment of a farm school for the University of California (at the time, Berkeley was the sole campus of the university).[185] The commission took a year to select a site for the campus, a tiny town then known as Davisville.[185]UC Davis opened its doors as the "University Farm" to 40 degree students (all male) from UC Berkeley in January 1909.
In 1919, the California Department of Food and Agriculture was established. The department covers state food safety, state protection from invasive species, and promoting the state's agricultural industry.
The Dust Bowl of the 1930s drove many people from the American prairie, and a significant number of these economic migrants relocated to California. Poor migrants from Oklahoma and nearby states were sometimes referred to as Okies, generally a pejorative term.
In 1933, the state saw a number of agricultural labor strikes, with the largest actions against cotton growers. Cherry, grape, peach, pear, sugar beet, and tomato workers were also involved.
In 1942, the United States began the Bracero program. Lasting until 1964, this agreement established decent living conditions and a minimum wage for Mexican workers in the United States.
1950–2000
In 1965, the Williamson Act became law, providing property tax relief to owners of California farmland and open-space land in exchange for agreement that the land will not be developed.
In the 2000s and 2010s, Californians voted for propositions which established new protections for farm animals. 2008 California Proposition 2 and 2018 California Proposition 12 both established minimum requirements for farming egg-laying hens, breeding pigs, and calves raised for veal.
Few veal and pig factory farm operations exist in California, so these propositions mostly affect farmers who raise California's 15 million egg-laying hens.[188]
Agricultural crime
California nut crimes have involved the theft of millions of dollars of nuts (almonds, pistachios, cashews and pecans) in multiple incidents since 2013.[189][190]
Water theft for agriculture has been an issue in times of drought, with the State assessing fines up to $1.5 Million.[191][192]
Pests
Despite its expansive geography some pests are so severe, so polyphagous, and/or so wide-ranging as to be economically significant to the entire state.
The Navel orangeworm (Amyelois transitella) first entered from Arizona in 1942 and quickly began attacking walnut, date palm, and fig.[193] (See § Walnuts, § Dates, and § Figs. Despite its common name, being only a minor pest of citrus.)[193] In the decades since it has become a notorious pest of almond, pistachio,[193][40] and pomegranate and remains problematic for walnut[40] and fig[40][41] as well.[40] (See § Almonds, § Pistachios, and § Pomegranates.) First flight of NOW begins around April 17 and ends around May 29, and third flight is about August 8 to September 12.[40][41] Second flight is not as much of a concern.[40][41]
Olives throughout the state suffer from the introducedOlive Fruit Fly here.[67] First detected outside its traditional Old World co-occurrence with the host tree in Los Angeles County in November 1998, it has since spread throughout California and into Baja and Sonora.[67]
The Glassy-winged sharpshooter (GWSS, Homalodisca coagulata, syn. H. coagulata) is a vector of Pierce's Disease and other Xylella fastidiosa diseases here.[198][53][199][200] Probably present since the late 1980s, the GWSS was only confirmed here in 1994.[199] GWSS was not obviously a threat until August of 1999 when it vectored PD to over 300 acres (120 ha) of vineyard in Temecula, Riverside County, forcing its destruction.[199] GWSS was first detected in Solano in November 2021, and although as of July 2022[update] absent from adjascent Napa is considered a high risk for introduction.[201] The staff of the Napa Agriculture Commissioner does inspections of all material entering the County to prevent that from happening.[201]
In 1997 the Blue-Green Sharpshooter (BGSS, Graphocephala atropunctata, the primary PD vector) arrived here and the two have combined badly ever since.[202] Besides vectoring PD they are also themselves a sucking pest and Hewitt et al., 1949 found they will often additionally go through reproduction on the vines.[56] See § Pierce's Disease, § Grapes, and § Xf in stonefruit.
The European Grapevine Moth (Lobesia botrana, EGVM) was present from atleast 2009 through 2014.[54] A 10 acres (4.0 ha) block in Napa suffered a 100% crop loss in 2009 due to a burrowing worm.[54] This was confirmed to be the EGVM by Gilligan et al., on September 30th, 2009 (published in 2011).[54] (It is native to southern Italy and may have arrived elsewhere in the state, possibly being detected as early as 2007 by Mastro et al., and published in 2010).[54] Both USDA and CDFA impose quarantines if two moths are found within 3 miles (4.8 km) of each other within one lifecycle span.[54] At first the quarantine zone was 5 miles (8.0 km) around the detection sites.[54] In 2010, 40,000 traps revealed an expanded presence – in Fresno, Mendocino, Merced, Monterey, Napa, San Joaquin, Santa Clara, Santa Cruz, Solano, and Sonoma.[54] The first detection in Sonoma was around Kenwood on March 29th, 2010, then a total of 59 across the County that year.[54] In 2011 only nine were detected on two sites in Sonoma, and despite the quarantine the pest spread to Nevada County in 2011.[54] The quarantine was lifted in Fresno, Mendocino, Merced, and San Joaquin in February 2012, only one insect was found in Sonoma for the year, the quarantine was lifted in Nevada, Santa Clara, and Santa Cruz counties in December, and was greatly shrunk in Solano and Sonoma in the same month.[54] No detections occurred in Sonoma in 2013.[54] The quarantine was lifted in Solano in 2014 but one EGVM was found in Sonoma for the year and so the quarantine remained in Napa and Sonoma.[54] The last detection being in June of 2014 in Sonoma, all USDA and state quarantine and trapping activities ended with the declaration in August 2016 of a successful eradication.[54] See also § Grapes.
Japanese Beetle (Popillia japonica) has been repeatedly found here and repeatedly eradicated.[205] Monitoring and eradication continue especially because of the wide host range of the grubs but also due to the grubs' and adults' destructiveness.[205]
The Plum Bud Gall Mite was first confirmed here in Santa Clara County in February of 2019, but may have been found in northern Marin in early 2014.[93] Certainly since 2019 it has become widespread in the Bay Area, as of 2021[update] reaching Contra Costa, Alameda, San Mateo, Santa Cruz, Sonoma, and north into Western Oregon.[93] So far PBGM is known to be a problem on plum and pluot (see § Plums) and not on other stonefruits, especially not almond, even almonds nearby to infested orchards.[93]
The Silverleaf Whitefly (SLW, Bemisia tabaci strain B) was first noticed here in the fall of 1991.[206] First appearing in the valleys of the state's deserts, it has caused about $500 million in agricultural losses here through 2019.[206] Further economic effects include $774 million in lost sales, $112.5 million in lost personal income, and the loss of 12,540 jobs.[206]
Lygus bugs are common pests here including the Western Tarnished Plant Bug (WTPB, Lygus hesperus).[118] A vacuum collector is often used for WTPB in strawberry, called the BugVac.[207] (See also § Strawberry.)
The Peach Fruit Fly (Bactrocera zonata Saunders) has been repeatedly introduced and quickly eradicated here, in 1984[218] and in 2006.[219][153][154] Then on September 29th and/or 30th, 2020, three PFF were found in Chowchilla, Madera County.[153][154] This presents a tremendous hazard not only to the area but to the state, and indeed the entire country.[153][154] Because the pest may spread from here to other countries, trading partners including the EU and New Zealand are also concerned.[153][154] They are considering restricting importation of fruits and vegetables from the state.[154] As a result the Secretary of CDFA, Karen Ross has declared a biosecurity emergency and eradication efforts using methyl eugenol lures are underway.[153][154] Especially an immediate concern are California's $2.10b citrus-, $875m stonefruit, and $1.19b tomato industries.[153][154] (See also § Chowchilla, § Citrus, § Stonefruit, and § Tomatoes.)
The Green Fruit Beetle (Figeater Beetle, Cotinis mutabilis) is occasionally a pest of ripened fruit, including apricot, caneberry, fig, grape, peach, and plum.[220] The larvae/grubs are harmless however.[220]
X.fastidiosa was first discovered here by Newton B. Pierce (1856–1916) in 1892.[48][224] It has ever since remained a constant pathogen of many crops here.[225]
When European grapes were introduced to this area – Alta California – in the 1700s they died off repeatedly, primarily due to PD but also insect pests.[226] The natives here were already growing several native grape varieties, especially Vitis rotundifolia.[226] In the opinion of Scortichini[226] this demonstrates PD's presence in the state from antiquity, that native grapes had coevolved with Xf, and that this is the reason for the repeated failures of viticulture here until mixed European/American varieties were tried.[226] This unidentified problem known only as the California Vine Disease devastated 14,000 hectares (35,000 acres) of vineyard around Los Angeles in the 1880s and Pierce was sent by the USDA to investigate.[48] In 1882 Pierce[227] was able to identify that most of the failure was due to the disease, and less to the insects.[226] For Pierce's contributions to its study it was renamed Pierce's Disease in 1939 by the state Department of Agriculture.[48][228]
Whatever the time of arrival in California and in North America, the current PD-causing Xff strains here show very recent divergence – in the mid-1900s.[229] This is likely due to massive expansion – or even introduction – of the current Xff strains, replacing the pre-existing strains across the state as grape acreage expanded in the 1970s.[229]
PD was assumed to be viral until the 1970s.[48][228] The first isolation and identification of the bacterium is variously credited either to two groups simultaneously in 1973, Goheen et al., 1973 and Hopkins & Mollenhauer 1973,[48] or only to Davis, Purcell, and Thomson 1978.[228]
In 1997 the Blue-Green Sharpshooter (the primary PD vector) arrived here and the two have combined badly ever since.[202] (See § Blue-Green Sharpshooter.) Only two years later, in 1999 together they inflicted over US$6 million in Southern California alone.[202]
The CDFA's Pierce's Disease Control Program coordinates response and research in the state.[230]
Alston et al., 2013 estimates that PD cost the state $92m in 2013[50] and over Tumber et al., 2014 estimates $104m annually in 2014.[202]
GWSS remains a common vector of PD and as such is a severe drag on the entire continent's wine grape and table grape pricing and supply.[53] In the Napa- and Sonoma- Valleys and other such costal AVAs PD mostly occurs in hotspots adjascent to small water flows.[56] These areas are defined by small streams and ornamental irrigation.[56] These are favorable habitat for the BGSS.[56] Lin et al., 2005 provides SSRs for differentiating between the state's various from grape-, almond-, citrus-, and oleander-infecting strains and Lin et al., 2013 for grape-infecting strains here and in Texas.[48]
The BGSS is known to thrive in higher temperatures and PD epidemics are more severe in hotter years, and there is evidence that global warming is increasing BGSS transmission of PD here.[231] Larger data sets are needed for stronger confirmation.[231]
Xf in stonefruit
Xf is also significant in stonefruit here, causing Almond leaf scorch disease and other diseases.[225][48] (See also § Almonds.) Xf isolates CFBP8071 and M23 are common on almond here.[225] Moralejo et al., 2019 shed some light on the European invasion of this pathogen.[225] Their analysis shows these isolates have a 99.4% nucleotide identity with those on grape in the introduced range – and more generally, these isolates, a European cherry infection, and PD isolates from both areas have a high degree of relatedness.[225] Chen et al., 2005 provides PCR primers, Lin et al., 2015 Simple Sequence Repeats (SSRs), and Chen et al., 2010 the first genome sequence for common almond-infecting strains here.[48] Lin et al., 2005 provides SSRs for differentiating strains from grape, almond, citrus, and oleander[48] While almond and plum develop leaf scorch (see also § Plums), Ledbetter & Rogers 2009 find that peach does not.[48]
Besides Pierce's Disease, the glassy-winged sharpshooter also vectors Xf among stonefruit and so its arrival threatens the world's almond supply (see § Glassy-winged sharpshooter and § Stonefruit).[53]
Other Xf infections
Xf has many other hosts. Chitalpa tashkentensis is a common landscaping plant here and elsewhere in the southwest that is also a host.[48] Randall et al., 2009 propose the subspecies tashke for these strains but it remains unclear whether this is a distinct subspecies and whether it endures in the overall evolutionary course of Xf strains.[48] Hernandez-Martinez et al., 2007 find the subspecies sandyi causes disease of oleander, Jacaranda spp., daylily, and magnolia.[48] Grebus et al., 1996 discovered the Oleander bacterial leaf scorch syndrome.[48]
Grapevine red blotch losses in Napa County cost over $69,500 per hectare ($28,100/acre) across the likely 25-year lifetime of a vineyard, far higher than the $2,200 per hectare ($890/acre) estimated for eastern Washington.[50]
Grapevine leafroll-associated virus 3 (GLRaV-3) costs the state $90 million annually.[50]
Fungicides are used multiple times per seasons and as a result resistance is common.[110] Across one season, Cosseboom et al., 2019 finds the proportion of resistant isolates went from [110]
Alleles responsible include the erg27 alleles F196C, F412I, and F412S; bos1 alleles I356N, I365N, and I365S; the β-tubulin allele E198A (which Hu et al. 2016 finds has no fitness penalty); the cytb allele G143A (found by Veloukas et al., 2014 to have no fitness penalty); the mrr1 allele R351C and the mrr1 deletion event ΔL497 (also known as MDR1h and found only in Botrytis group S); and sdhB alleles H272R, H272Y, N230I, and P225F (the only one conferring resistance to isofetamid, also confers resistance to penthiopyrad, fluopyram, and boscalid, and associated by Hu et al., 2016 with resistance to fluxapyroxad).[110] The analysis of Cosseboom et al., 2019 explains 93.8% of resistance by already-known alleles discovered by Banno et al., 2008, Ma et al., 2007, Grabke et al., 2013, Kretschmer et al., 2009, Dowling et al., 2017, Fernández-Ortuño et al., 2012, Amiri et al., 2014, and Yin et al., 2011, so very little is due to experimental error, unknown physiological effects, or undiscovered alleles.[110] (See § Isofetamid, § Fluopyram, and § Boscalid.)
Organic strawberry ranches experience very active genetic transfer with conventional strawberry and as a result they have high proportions of resistance.[110] Cosseboom et al., 2019 finds that conventional fields undergo within-season resistance evolution, while organic does not, demonstrating that they are indeed not using the fungicides they claim to not use, and that genetic transfer is not so rapid as to change the situation in a field that quickly.[110]
Ma & Michailides 2005 developed a microsatellite primed PCR (MP-PCR) for genetic diversity in this fungus, especially for populations in this state.[232]Strawberry Botrytis leaf spot was first discovered in 2018 in Santa Maria and reported by Mansouripour & Holmes 2020.[111]Bc was not previously known to produce a leaf spot phenotype in strawberry.[111]
In table grape there is a limit of 0.5% – table grapes can only be shipped if an allotment contains 0.5% or less of Bc-infected berries.[51] For one treatment option for grape, see § Ozone.[51]
Black Heart is a common pomegranate disease worldwide. Out of the group of causative Alternaria spp., here Luo et al., 2017 find it is caused by Alternaria alternata and A. arborescens.[30]: 192 [235] Michailides et al., 2008 finds the 'Wonderful' cultivar can suffer at a rate of 10% or more here.[30]: 192 [236]: S105 (See also § Pomegranates.)
Olives here suffer from a wide range of fungal diseases of the Botryosphaeriaceae family, as elsewhere in the world.[68] Úrbez-Torres et al., 2013 finds Neofusicoccum mediterraneum and Diplodia mutila are the most virulent of them on Manzanillo and Sevillano.[68] Moral et al., 2010 finds N. mediterraneum commonly causes a branch blight on several cultivars and D. seriata causes a branch canker.[68] More specific controls than currently available are needed for N. mediterraneum in highly susceptible cultivars, and early harvest may be the only successful treatment for D. seriata.[68] See § Olives.
In early 2012 a previously unknown plant disease (a Fusarium) and vector (a Euwallacea, preliminarily termed the polyphagous shot hole borer, PSHB) were detected in Los Angeles and Orange Counties.[12] This is especially a disease affecting avocado growers, but also other crops in this state and in its other invasive range, in Israel.[12] In fact although PSHB was noticed on a black locust here in 2003, the associated Fusarium was only detected in 2012 on home avocado trees in LA County.[12] (See § Avocados above.) As all Euwallacea in both their native and invasive ranges, this insect prefers to infest hosts in this area in locations which are stressful due to their unnaturalness, such as urban ornamental plantings and orchards.[12]
Stripe rust is believed to have been a continuous presence in the state since at least the 1770s because newspapers reported it at the time on wheat and wild grasses, and because stripe is more common today than leaf or stem.[13]: 3 Barley, wheat, and various grasses are hosts here.[13]: 9 (See § Barley and § Wheat.)
Leaf Spot of Caneberry (Mycosphaerella rubi, anamorph Septoria rubi) is common here.[17] It is common on caneberry excluding raspberry, so erect and trailing blackberry, dewberry, olallieberry, and boysenberry.[17] (See also § Caneberry.) Treatment is simple, almost entirely relying on increased air circulation.[17] No fungicides are registered but any fungicides for § Anthracnose and § Gray Mold will work.[17]Copper and lime sulfur work to some degree.[17]
This should be distinguished from Leaf Spot of Raspberry (Sphaerulina rubi, anamorph Cylindrosporium rubi).[17] Although Leaf Spot of Raspberry is found here it is not common in California.[17][17] (See also § Raspberry.)
Phytophthora ramorum was first discovered in the 1990s on the Central Coast[239] and was quickly found in Oregon as well.[240]P. ramorum is of economic concern due to its infestation of Rubus and Vaccinium spp.[240] All isolates here and throughout North America have been of the A2 mating type and genetic analysis suggests that although it was discovered here, the pathogen originated elsewhere.[240] Although P.r. has also been found in England and Poland,[239] Europe was not the source of the introduction here and analysis shows that it too was introduced from an unknown third region.[240]
Verticillium Wilts (biovars of Verticillium dahliae) are found here as in any other ecozone. This includes Verticillium Wilt of Strawberry.[241] Unlike every other known Vert Wilt of any other crop, this syndrome sometimes lacks any or any noticeable vascular discoloration of the crown.[242] In strawberry, methyl bromide has historically been vital to prevention, and with phase out, this disease is of increasing concern.[241] (See § Methyl bromide.) In all cases some fumigation is necessary, and if fumigation is not possible then solarization and/or rotation are the only remaining options.[241] (See § Soil solarization.)[241] Although drip fumigation (fumigation inline in the drip tape) is possible it does not produce the same results, especially failing to reach the shoulders of the beds.[241] Nurseries universally use MB or MB + chloropicrin, while growers may use 1,3-D + chloropicrin, chloropicrin alone, metam sodium, or metam potassium.[241] (See § Chloropicrin, § 1,3-dichloropropene, § Metam sodium, § Metam potassium.)
Fusarium Wilt of Strawberry (Fusarium oxysporum f. sp. fragariae) had only been seen once before, in Queensland, in one sample of Winks & Williams in 1966,[243] until appearing again here in 2006 and identified by Koike et al. 2009.[244] As of 2018[update] it has spread throughout the state.[113] For genetic resistance see § Diseases of strawberry.
Lindane was heavily used as a seed treatment here, applying almost 5,000 pounds (2,300 kg) in 2000 but voluntarily reducing that to only 775 pounds (352 kg) by 2004, before the federal EPA banned it for agricultural use 2006.[247]
Fungicides are heavily used especially in fruit production. Adaskaveg et al., 2005 finds no compromise in effectiveness when substituting lower-toxicity fungicides for older, higher-toxicity ingredients.[248] They find a boscalid + pyraclostrobin mixture, fenhexamid, fludioxonil, and pyrimethanil to be good substitutes for the more toxic dicloran, iprodione, and tebuconazole.[248] (See § Boscalid, § Pyraclostrobin, § Fenhexamid, § Fludioxonil, § Iprodione.) Older fungicides also have generally experienced much slower resistance evolution than newer ingredients.[88]
Methyl bromide was formerly an indispensable part of strawberry cultivation here but increasing legal restrictions have made alternatives financially more attractive, otherwise more attractive, or even just necessary.[69]
Pyraclostrobin, thiophanate-methyl, fenhexamid, cyprodinil, boscalid, pethiopyrad, iprodione, fluopyram, fludioxonil, and isofetamid (in descending order) suffer extensive resistance due to repeated sprays many times per season in strawberry here.[110] The team performing this research, Cosseboom et al., 2019, also surprisingly found that this is such a problem that within-season evolution is significant, especially in the north and especially in fenhexamid, pyraclostrobin, and thiophanate-methyl.[110] In fact, if there was any resistance at all it was most commonly triple resistance to these three.[110] They suggest thiophanate-methyl should not be used at all.[110] Adaskaveg & Gubler 2006 and Billard et al., 2012 find fenhexamid resistance carries a fitness cost however, so rotating it out for a time may restore its efficacy.[110] Johnson et al., 1994 and Raposo et al., 1996 find suggestive evidence for the same in iprodione.[110]
Captan is by far the most commonly used fungicide in strawberry,[110] see also § Strawberry.
The Diaphorina citri-associated C virus (DcACV) is a virus of the Asian citrus psyllid.[250] It was first identified by Nouri et al., 2016 in isolates from this state.[250] It is hoped that this can be weaponized as a bioinsecticide of ACP, a virus to be intentionally spread outside of the state to help control this insect.[250] (See also § Citrus and § Asian citrus psyllid above.)
DDT was formerly extensively used in citrus here.[33] Honeybees developed DDT resistance in the 1950s, possibly for that reason.[33] (See also § Honeybees.)
Methyl anthranilate is registered as a bird repellent for edible fruits such as cherry, apple, blueberry, and grape.[29] (See also § Birds in fruits.)
The moth Digitivalva delaireae predates on the invasive weed Cape-ivy.[251] (See § Cape-ivy.) In food preference tests, Mehelis et al. 2015 find that the moth is so selective about preferring Cape-ivy that it would serve well as a safe biocontrol here and in Oregon.[251]Cercospora delaireae is a fungus which has been found on the same weed in its native range.[252] It can be used as a biocontrol as well.[252]
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