- Author: Saoimanu Sope
San Diego County used to be home to nearly 25,000 acres of avocado trees but today there are about 14,000. The drastic decrease is largely due to rising costs associated with avocado production, namely the cost of water.
On September 28, avocado growers gathered at the San Diego County Farm Bureau offices for an Avocado Irrigation Workshop facilitated by Ali Montazar, University of California Cooperative Extension irrigation and water management advisor for Imperial, Riverside and San Diego counties.
“All of our information being developed right now is focused on [irrigation] efficiency. Growers want to know how much water they need and what tools they should use to be more efficient,” explained Montazar.
Workshop attendee John Burr, who has been growing avocados for 15 years, confirmed that irrigation represents over half of his annual production costs and that meeting the needs of his trees is a constant challenge.
“The sophisticated research in avocado irrigation that Dr. Ali Montazar is conducting is the first of its kind that the University of California has carried out specifically in avocados. His presentation allowed us attendees the opportunity to see and learn about the technology he is employing – from soil moisture sensors to the California Irrigation Management Information System level equipped station.”
Burr is hopeful that Montazar's research will help avocado growers accurately determine the evapotranspiration in an avocado grove or water use specific to avocados, critical parts of how growers select tools to determine irrigation runtimes.
“His presentation that showed his research finding of the avocado Kc (crop coefficient), while very early into his project, was really interesting. It indicates the possibility that we may need to vary the Kc for different times in the growing season, but he is just beginning a two-to-three-year project that will hopefully deliver solid data on what the Kc for avocados is,” said Burr.
Colorado River uncertainty looms
San Diego's avocado production is primarily managed by small farms. According to Montazar, this adds a level of complexity to water management because there is a greater emphasis on irrigation tools and strategies being user-friendly and cost-efficient.
“We don't know the future,” said Montazar. “But we need to be prepared for all consequences. The Colorado River is experiencing a significant water shortage, and this could impact the water supply source for San Diego County from the Imperial Irrigation District Transfer in the future. It is wise to consider enhancing irrigation efficiency as the most viable tool to manage limited water supplies in Southern California.”
Water has always been an issue. In the 1970s, California's water program paved a way for an additional 98,000 acres of agricultural land.
According to a 1970 study analyzing the cost of avocado production in San Diego County, water costs “averaged 3½ acre feet per acre at $60 an acre foot,” which came with the assumption that water costs would remain relatively low and affordable for a long time.
Unfortunately, that is no longer the case. The county of San Diego gets the majority of its water from the Colorado River, which is concerning given five-year projections of the river reaching critically low reservoir levels by 2027.
In fact, beginning in 2023, the San Diego County Water Authority will be raising the rates for water, prompting growers to invest in more efficient irrigation practices (Table 1).
Table 1. Cost for untreated and treated water in San Diego County in 2022 and 2023.
NOTE: An acre-foot is about 325,900 gallons of water.
Training growers on irrigation a top priority
There are no loopholes or short cuts when it comes to irrigation because irrigation is the key to tree health. Ben Faber, Cooperative Extension subtropical crops advisor for Ventura and Santa Barbara counties, points out that tree health is how growers stay in business.
“You can mess up your fertilization program, and you can mess up your pesticide program, but if you mess up your irrigation program, you're out of business,” he said.
According to Faber, efficient irrigation requires a strong grasp on salt management.
“We import water that has a lot of salt in it. So, you've got to figure out how to put the right amount of water on the root zone without causing root health problems,” said Faber.
This process requires meticulous care, as anything that gets below the root zone can cause groundwater contamination – something growers do not want to be responsible for.
While the latest irrigation technology, such as smart controllers, could help growers, Faber said that training and educating farm managers should be the priority.
As Faber puts it, managing irrigation should be “like brushing your teeth” – something that growers do naturally and competently. Many growers are over-irrigating or wasting time trying to resuscitate dying trees. It's important to learn the needs of the tree and, in some cases, it might be best to stop watering all together.
The first step to water efficiency is acquiring knowledge and identifying needs. Because an over-irrigated tree looks just like an under-irrigated tree, it's crucial that growers learn to recognize the difference and plan accordingly.
This is where Cooperative Extension advisors and researchers come in. Opportunities like the Avocado Irrigation Workshop are ideal for growers looking for answers or support.
For more information and to learn about future workshops in San Diego County, visit https://cesandiego.ucanr.edu/.
/h3>/h3>
- Author: Ben Faber
Pruning is a difficult topic to discuss and describe and to arrive at a consistent approach from year to year.
And now Simon Newett, Bridie Carr and Renata Grunennvaldt have put together a survey of what avocado growers worldwide are doing to control vegetative growth. The survey was conducted through an avocado industry extension project funded by Australian grower levies, Hort Innovation Ltd (Australia) and the Queensland governments (Hort Innovation Limited & DAF). Thank them for their efforts.
Obviously the methods and results reported in the survey will vary according to the characteristics of the orchard and the environment in which the trees are grown. And whether a plant growth regulator is used, such as uniconazole or propiconazole, to retard growth.
The most interesting findings were the popularity of selective limb removal, the younger tree age in which pruning is now commenced, the smaller tree size being aimed for and the fact that most people try to remove about 20% of the canopy each year.
Check out what other growers are doing in their orchards by clicking on the link at the bottom of the page.
- Author: Hung Kim Doan
California continues to face escalating drought conditions and as a result, Control Section 11.85 of the Budget Act of 2021 allocated $5 million for direct drought relief funds which will be administered through the CUSP (California Underserved and Small Producers) program partner organizations throughout 2022. The grant is provided by the California Department of Food and Agriculture and funds small-scale farmers of color, immigrant farmers, and undocumented farmers directly impacted by the drought.
Covered Expenses:
- Increased electric utility bills of 50% or more due to increased electricity rates
- Surface water costs if increase from year prior
- Cost of hauling water for livestock
- Lowering ag well pumps if a primary source of water is lost
- Emergency upgrades to irrigation system (paired with conservation) if not covered through CDFA OEFI programs or USDA programs and for other emergency scenarios.
- Decreased crop yields/crop loss due to less water available or having to fallow land
Not Covered:
- Drilling new well
- Upgrading pump to a larger size which would draw more water
How can farmers apply?
Farmers who have received a COVID relief grant will be eligible for drought relief funds one calendar year (12 months) after applying for economic relief funds.
For more information, please contact Hung Doan (hkdoan@ucanr.edu; (951) 455-5726 )
California Avocado Society 1968 Yearbook 52: 29-34
PREHISTORIC AVOCADOS IN CALIFORNIA
C. A. Schroeder
University of California, Los Angeles
The original avocado found in the area now designated California can be related to
prehistoric times, namely the middle Eocene and Pliocene epochs which have been
determined by geologists to be approximately 10 to 60 million years ago. The history of
these progenitors of the modern avocado and close botanical relatives in our current
Perseaspecies is recorded in fossil remains embedded in rocky outcroppings and in
formations exposed comparatively recently by the work of man as he sought gold in
California. Hydraulic mining practiced to excavate and wash the mountains of the
mother-lode country released many fossil specimens which had been buried deep in the
soil and revealed numerous plant materials which indicate the extensive and probable
dense semi-tropical flora that once existed. The semi-tropical climate of this period was
much in contrast with the more arid climate of today which provides the sclerophytic-
xerophytic chaparral and open pine associations now prevalent in the Sierra foothills.
The descriptions of the fossil flora of California and nearby Nevada are provided
primarily in the researches by Axlerod (1-7), MacGinitie (11), Chaney (8), Condit (9-10),
and Putnam (12) who have studied the fossil records of collections in the extensive
holdings of the University of California Museum of Paleontology at Berkeley and at other
museums in California. This report is primarily a brief account of their extensive studies
TheabundantevidencethattheclimateofCaliforniahasundergonedramatic
modification since prehistoric time is deducted from the paleobotanic and geological
studies of several sites in California and Nevada. The slow evolution of climatic changes
which has occurred through the ages is reflected in the types of flora and the specific
plant and animal materials associated with the collections and interpreted in light of
knowledge of present day similarities. The presence of avocado-like plants has been
clearly established in the fossil collections from Central and Northern California, and
they are particularly numerous in the Palmdale area. Those poleobotanic studies have
been made entirely on fossil leaf remains which are in some cases most excellently
preserved in the rock. Unfortunately, the more fragile flowers and fruits have not been
preserved, hence were lost during the formation of the fossil bearing soils.
Distribution of ancient avocados probably extended throughout the present state of
California is indicated by collections made in such widely separated areas as Mint
Canyon near Palmdale, Mulholland near Oakland and Nevada City, California. That the
speciesPersea coalingensisand other botanical relatives extended beyond the present
California borders is evident from the collections in Middlegate, Nevada (12) and in
Oregon (8). While the avocado is found as a representative among the flora in several
areas, it possibly was a dominant species in some areas such as in the site near
Palmdalewhereitcomprised68%ofthetotalspecimenspreservedunderthese
specific conditions. Other species associated withPerseabut in lesser numbers near
Palmdale werePopulus(cotton wood),Quercus(live oak) andPlatanus(sycamore).
Axlerod (7) indicates thatPersea"lived in large numbers along the river banks and lake
borders of the region". The density of ancient avocado in other areas of California
possibly was 10% or less of the total flora.
The distribution ofPersea coalingensisin the Pliocene deposits of California together
with such species asJuglans(walnut),Platanus(sycamore),Quercus(live oak) and
Salix(cottonwood) together with fossil horses, camels and antelope is interpreted to
indicate the semi-arid woodland habitat with considerable grassland in the vicinity (5).
Species ofMagnoliaandPerseapresently found in the semi-arid areas of northern
Mexico indicate a relationship to the fossil specimens from California. This has been
interpreted to indicate that the ancient flora of California was historically a relic of the
Caribbean Element comprising a dominant feature in Central California in the Eocene
and surviving in the more coastal situations in the late Tertiary (8). The common
Pliocene fossil speciesP. coalingensisis related to the livingP. padeniaBlake of the
Sierra Madre Occidentale in Sonora and Durango, Mexico (8).
The botanical relatives within the family Lauraceae abundant in early Tertiary consisted
of possibly more than eight species. Some of these have living relatives in various parts
of the world today but only one,Umbellularia californicaNutt, has survived in California.
AmongthefossilspecimensfoundinCaliforniaareCinnamomumacrodomum,
Cryptocaryapraesamarensis,Laurophyllumfremontensis,Neolitsealata,Persea
praelinque, P. pseudo-carolinensis, P. coalingensisandUmbellularia salicifolia(8).
These species were scattered throughout the present State of California in prehistoric
times and are represented today only by botanical relatives found in Sonoran Mexico
and the remnant related species,Persea borbonia,the swamp bay of the Southern Gulf
States
The association of ancientPerseawith such genera as Magnolia provides evidence for
the existence of a climatic condition such as that encountred today in the warmer and
more humid areas of the Gulf states of Mississippi, Alabama and Georgia.
Among the most ancient of plant fossils which have been collected and identified from
California were those from sites in the San Francisco Bay area. These specimens are
representatives of a semi-tropical flora including the fan palm(Sabalites),magnolia,
sebestena (Coraza), huanchal(Cupania]and avocado(Persea)(8). The vegetative
characteristics of these genera are generally large and thick leaves compared to the
smaller, thin leaves of species from the temperate regions. The nearby presence of
fossil marine animals indicates the probable existence of swamps or lagoons which
again provides evidence suggesting climatic conditions of high rainfall and relatively
high atmospheric humidity.
Thecriteriaofdiagnosisandidentificationofgeneraandspeciesinfossilleaf
specimens consist of morphological variations in leaf form and the detailed pattern of
the venation, the angle of departure of secondary veins from the midrib, the straightness
or curvature of secondary veins and the characteristics of primary nerves which arise
from the leaf base.
Identification of fossil impressions is made by comparison with present day living
species or botanical relatives.Persea carolinensis,an extinct species, for example, is
quite similar in leaf form and venation to the living types,Persea borboniaorPersea
paulustria,the Swamp or Bull Bays, presently extending from Florida to Texas in the
Gulf Coast area.
The remaining living botanical relatives of the ancient California avocado, Persea, is
Umbellularia californicaNutt., commonly called the California bay, California laurel,
Peppernut, or California myrtle. This bushy tree may attain a height of 6 to 15 meters,
18-48 feet. The long lanceolate leaf has a strong penetrating odor when crushed. The
fruit is a small inedible drupe about 2 cm. long. The seed can he eaten after roasting.
This species is found commonly in dry cismontane canyons below 5,000 feet elevation
from San Diego County to Oregon. The wood from older, larger specimens is used for
turning howls and other art objects as it has a beautiful grain and takes a good polish.
This wood is sometimes called California or Oregon myrtle.
A rough concept of the age of prehistoric avocado in California is depicted in Figure 2.
The geological time scale expressed in the great epoch terminology suggests the
presence of avocado in the Eocene, possibly 50 million years ago. The flora of that
period probably varied much as it does today but some of the genera maintained their
presence until Lower Pliocene about 10 million years ago. The close botanical relative,
Umbellularia,survivedtheintervalfromLateMiocenethroughthePlioceneand
Pleistocene and appears today somewhat modified but vigorous and plentiful in the
coastal and mountain valleys as our California Bay tree. Man appeared on the earth
only in very recent geological time. His active presence in California probably can be
well established only to three or four hundred years ago.
LITERATURE CITED
1.AXLEROD, D. I. 1939 A Miocene Flora for the Western Border of the Mojave Desert.
Carnegie Institute, Washington Contrib. Paleo. Publ. 516.
2.AXLEROD, D. I. 1944 The Sonoma Flora. In: Chaney, R.W., Pliocene Flora of
California and Oregon. Carnegie Instiit., Washington Publ. 553. pp. 167-200
3.AXLEROD, D. I. 1944 The Mulholland flora. Carnegie Inst. Wash. Publ. 553, pp.
103-140.
4.AXLEROD, D. I. 1950 A Sonoma Florule from Napa, California. Carnegie Instit.
Washington. Publ. 590. pp. 25-71.
5.AXLEROD, D. I. 1950 Further Studies of the Mount Eden Flora. Carnegie Instit.
Washington. Publ. 590. pp. 75-158.
6.AXLEROD, D. I. 1950 The Piru Gorge Flora of Southern California. Carnegie Instit.
Washington Publ. 590. pp. 161-214.
7.AXLEROD,D.I.1950AnaverdeFloraofSouthernCalifornia.CarnegieInstit.
Washington. Publ. 590. pp. 121-158.
8.CHANEY, R. W. 1951 Prehistoric forests of the San Francisco Bay area. In: Jenkins,
O. P., Geologic Guidebook of the San Francisco Bay Counties. Calif. Div. of Mines.
Bul. 154: 193-202. 1951.
9.CONDIT, C. 1944 The Remington Hill Flora. In: Chaney, R. W., Pliocene Flora of
California and Oregon. Carnegie Instit. Washington. Publ. 558. p. 21-55.
10. CONDIT, C. 1944 The Table Mountain Flora. In: Chaney, R. W., Pliocene Flora of
California and Oregon. Carnegie Instit., Washington. Publ. 558, pp. 57-90.
11. MAC GINITIE, H. D. 1941 A Middle Eocene Flora for the Sierra Nevada. Carnegie
Instit. Washington Contrib. Paleo. Pub. 534.
12. PUTNAM, W. C., C. DURRELL and G. TOMEL 1956 Mio-Pliocene Floras from
West-Central Nevada. Univ. Calif. Publ. Geol. Sci., Vol. 33
Umbellularia californica with flower and unripe fruit, the "bay nut". California Bay Laurel, also known as Oregon Myrtle, California Bay Tree, California Laurel, Pepperwood, Spicebush, Cinnamon Bush, Peppernut Tree and Headache Tree. Looks like avocado?
- Author: Ben Faber
You wanted to see where all those ants are coming from? Well here is the site to see what ants are where with their descriptions and images.
The ant fauna of California comprises 8 subfamilies, 44 genera and approximately 300 species (of which 30 are introduced). About 25% of the native species are endemic to the state or to the California Floristic Province (including northern Baja California and southern Oregon).
https://www.antweb.org/adm1.do?name=California&country=United+States
Prominent California ants include seed-harvesting species in the genera Veromessor, Pheidole and Pogonomyrmex; honeypot ants in the genus Myrmecocystus; a diverse array of species in the genera Camponotus ("carpenter ants") and Formica; native fire ants (Solenopsis spp.); velvety tree ants (Liometopum spp.); and the introduced Argentine ant (Linepithema humile). This last named species is particularly common in urban and suburban parts of California, where it establishes dense populations and eliminates most native species of ants.
This web site provides color images and identification information for most of the species of ants known to occur in California. For identification of pest ants you may find it useful to consult the key to common household ants of California developed by the UC Statewide IPM Program.
Specimens: 15,612
Images: 655
Imaged Specimens: 981
Subfamilies: 8
Genera: 44
Species/Subspecies: 305
Valid Species/Subspecies: 266
Endemic: 26
Introduced: 23
Show All Specimens
https://www.antweb.org/about.do
AND WAIT, THERE"S MORE - ALEX WILD'S SITE HAS EVEN MORE WONDERFUL IMAGES AND HISTORIES OF ANTS
https://www.alexanderwild.com/Ants
Plus a menagerie of other Insect images - https://www.alexanderwild.com/Insects/Portfolio/
Check it out
And if you want to get down with the Argentine Ant. Don't forget the Workshop next week
Argentine Ant Workshop and Registration
David Haviland says the best Ant Costume wins free admission. Actually it's free to all who register for the meetings.
/span>