Observations from a Trip Down Under – The Australian Almond Industry

During the first two weeks of November, I was able to attend the once-every-four-years International Research Congress on Pistachios and Almonds. This meeting was held in Adelaide, Australia in which almond and pistachio researchers (as well as some growers) attended to discuss recent research within these crops. Prior to the conference, I toured some orchard operations in the Mildura area. These orchards had the look and “feel” of California orchards and  yields in the 2700-3000 lbs/acre. Through the visits and discussions with my various hosts, issues that many of the operations were trying to manage were similar but different to what we experience within California. Below are a selection that I found interesting and thought I would share. Good water management can compensate for limiting soils. Across all of the properties I visited, the soil profile was very shallow with  18-24″ of sand before hitting a limiting layer of clay. To make matters worse, the layer of clay often had a very high pH (>9) and boron (>3.0 ppm) – which would kill almond trees. These conditions reduced the rootzone to the sand profile which has limited water and nutrient holding capacity. To compensate for these “shallow soils,” most orchards are planted on a raised bed and irrigated daily with double drip systems to match the tree’s water demand for that day. The water applied does not exceed the holding capacity of the 24″ of soil to prevent root movement into the deeper toxic soil. This practice also prevents excess water from running off or creating a perched water table. This was an “eye-opening” experience for me. We generally have the luxury of deep soils within California in which we can irrigate deeply, less frequently. These irrigation practices, however, produced tree growth and yields which were comparable to California orchards.

November 28, 2017

About Me

David Doll The Almond Doctor The Almond Doctor is a website that shares research, experiences and opinions of better farm management practices for almond orchards. David was raised in a rural area growing apples and peaches. After attending Purdue University for his B.S. in Plant Biology, he attended graduate school at UC Davis, completing his M.S. in Plant Pathology. Shortly after completion, he started to work as a Farm Advisor the University of California. After ten years of working as a Farm Advisor, David made the move to Portugal in November 2018 to work as the lead developer for Rota Unica Almonds. His task is to develop California styled almond plantations within Alentejo. Through this process, he has become familiar with some of the various challenges associated with growing almonds in Portugal and Europe. Prior to his move, David worked with farmers in the Central Valley of California in troubleshooting problems and conducting on farm research within almonds, walnuts and pistachios. In this position, he would visit nearly 200 operations and deliver 35 presentations annually as well as publish regularly in scientific journals. Currently, he works with almond operations across the world, including Australia. Many of his observations and lessons learned have been shared within his online platform, “The Almond Doctor.”
October 16, 2017

Where are Leaffooted Bug Overwintering?

Written by Kris Tollerup, University of California Cooperative Extension Area-wide IPM Advisor, Kearney Agricultural Research and Extension Center, Parlier, CA For a few seasons now, I have been interested in understanding more and ultimately finding better monitoring tools for Leaffooted bug, Leptoglossus spp.  Most growers and PCAs have a  good working knowledge of this bug and likely have attended one or more of my talks covering the subject.  We know that leaffooted bug overwinters in aggregations consisting of just a few to several hundred individuals.  The aggregations tend to occur on citrus, palm frowns, Cyprus trees, pomegranate, walnut (Fig. 1), olive, and on/in non-plant substrates like pump houses, farm equipment, and wood piles.  The list is extensive.  The reason why aggregations can occur on such a diversity of substrates is that they are not necessary interested in feeding but more so in seeking a protected area to survive winter.  An  interesting behavior that I have made is that aggregations typically occur where the group can best collect heat from the sun during peak solar radiation periods.  In spring or as early as late winter, individuals begin leaving aggregations.  I, as well as other researchers, found that dispersion is closely associated with temperature and not necessarily dependent on other environmental factors such as day length.  I observed some moderately large aggregations on pomegranate in Tulare Co. and after warm mid-February temperatures of about 80 F, nearly all the LFB dispersed.  To particularly where, at that early time in the season, we did not determine.  The site had neighboring plantings of citrus and olive, which we surveyed but did not observe LFB in those crops.  Typically at mid-March, LFB starts moving into almond and history shows that they can cause substantial economic damage.  Because of work conducted by a host of researchers

February 5, 2017

2016 Top Ten Articles

With 2016 coming to a close, here is a quick review of the top ten articles read this past year from “The Almond Doctor.” 10. Verticillium wilt of almond (and pistachio). An overview of the disease, symptoms, and management for almond trees. This disease has become more common with increased plantings on land previously cropped to tomatoes and cotton. 9. Bacterial spot vs anthracnose vs plant bug. A series of pictures and a table to help identify the symptoms of these diseases or insect damage. 8. Postharvest is a good time for boron foliar sprays. A review of some research and considerations when making fall boron applications.  7. Independence almond – some observations. A 2010 article that highlighted some early observations of Independence. This variety is becoming more widely planted with an estimated 200,000 acres in the ground.  6. Almond set and nut drop. Summarizing recent research as well as field observations, this article discusses spur dynamics and the various “drops” of almond fruit. 5. 2016 almond bloom considerations. An annual contribution highlighting considerations for the upcoming bloom. 4. Proper almond tree planting. An article written by Brent Holtz back in 2010.  3. Fertilizing young almond trees – a few tips. With all of the newer orchards planted the past few years, this article has been read with increased frequency. 2. The seasonal patterns of almond production. An article about tree physiology and almond production. One of the first articles written for “The Almond Doctor” back in 2009. 1. Nitrogen content in a gallon of UN-32. A short article written in 2010 that provided an answer to a question commonly received. This one was number one last year as well! I would like to thank you all for your support through 2016. We develop many of the ideas for these articles through your requests for visits, phone calls, emails, and

December 31, 2016

Sun Reflecting Products for Increased Winter Chill? 

Written by Bob Beede (UCCE Kings County, Emeritus) and David Doll (UCCE Merced) Tests of winter applied kaolin clay or calcium carbonate-based materials intended to either reflect solar radiation or diffuse it continue.  Results from David Doll, UCCE Farm Advisor, Merced County, and Valley Orchard Management, showed an increase in chill portion accumulation and a 200 to 250 pound increase in CPC yield over untreated trees when kaolin-clay was applied prior to the 2015 season. More can be found here.  The data thus far suggests that spraying these materials to mitigate the negative effects of warm winter temperatures does not assure you of a normal crop, but it might prevent NO crop! This past winter, Carl Fanucchi and Bob Beede collaborated with ORCAL, the company which manufactures ultra-fine, dry ground calcium carbonate, which is marketed in liquid form as Mask® and Diffusion®. They performed UNREPLICATED screening trials in two locations; one in Buttonwillow, and the second east of Highway 99 on Pond Road.  The screening trials included single and double applications applied January 12 and February 12.  A December treatment was planned, but the field could not be accessed.  Flower bud temperatures were monitored in treated and untreated areas using tiny thermocouples inserted into the buds without causing their death.  The resulting data showed bud temperatures were reduced by as much as 100F, and the rate of heating during the morning hours was also slower.  Calculations indicate that the January treatment increased chill portion accumulation by about 13%, due to the lower bud temperatures.  Weekly rating of the treatments for bud break and bloom were also performed.  The treated trees emerged more evenly, and the second treatment of Diffusion applied in February delayed development by four to five days.  The single January treatment developed at about the same rate as the untreated. 

December 14, 2016

Winter Chill Update: December 2016

Written by Bob Beede, UCCE Kings County, Emeritus. Editors note: This article was developed with high chill crops, particularly pistachio. Almonds aren’t as chill dependent, but the broad topics discussed are relevant to all perennial horticultural crops. Those of you who are outside every day know that it has been pretty warm.  The only cold weather occurred during the first week of December in which many locations within the Central Valley experienced three to five days of temperatures ranging from 30-320F.  The Colusa CIMIS station reported 260F the morning of December 6.  Table 1 provides the chill portions for various sites throughout the Valley between September 1 and December 13 for the past four winters, as well as 2010 in which over 70 chill portions were accumulated by February 15.  This exceeds the 58-60 chill portions estimated to satisfy the rest requirement of the Kerman cultivar. The Peters male may have a chill portion requirement as great as 65.  The values in parentheses are the total chill portions accumulated by station and year.  2013 and 2014 were significantly warmer than 2010, in which dormancy was well satisfied throughout all areas of the state.  The 2015 data shows good chill accumulation was well on its way throughout the Central Valley in mid-December, and continued cold temperatures through January contributed to the record 2016 crop.  In contrast, 2014 was already showing deficient chill accumulation at several locations by mid December.  The Arvin/Edison and Coalinga stations might be considered the “canary in the coal mine” for early assessment of future low chill winters.  As you can plainly see, chill portion accumulation is not good thus far, and in some locations, less than the 2014 winter. Table 1. Chill portion accumulation for various CIMIS stations statewide from 9/1-12/13 for selected years. Numbers in parentheses are

December 14, 2016

Catch frame shaker sets in almonds?

Almonds are typically shaken to the ground by a side mount or boom shaker, allowed to dry where they fall for several days to weeks — depending on drying conditions and ant pressure – and then windrowed and picked up.  Once nuts are on the ground, no water should be applied to the orchard to avoid wetting nuts on the ground.  Depending on local conditions – how dry the soil was ahead of harvest as well as weather after shaking, if irrigation is applied between harvests of different varieties, etc.  – traditional harvest practices can result in water stress in the orchard, leading to measurable yield reduction in future years. Recently, some growers have moved to shaking and sweeping within 24 hours. The windrows are then conditioned (picked up, leaves and dirt blown out and dropped back on the orchard floor in a wide, shallow windrow) and left to dry out in the orchard middles.  Growers with micro- irrigation can irrigate (at least a little) once the windrows are down, reducing water stress in the orchard compared to a traditional shake-dry-windrow-pickup harvest.  This practice can reduce the time between shaking and pickup by 48 hours. Another alternative to traditional almond harvest is the use of catch frame shaker sets instead of shake-to-the-ground (no catch) machines (see photo).   Catch frame shaker sets (two machines; a shaker side and a receiver side) are used to harvest prunes and pistachios up and down the state.  Recently I watched a stock prune/pistachio catch frame set harvest almonds in a mature (10th leaf) orchard on Lovell rootstock on Class 2-3 soil at the Nickels Soil Lab near Arbuckle.   This orchard recently had the buried drip hose replaced and the orchard floor surface was rough under the trees.  A catch frame harvest was used to get

August 8, 2016

Managing Water Infiltration Problems

Over the past few weeks, there have been several farm visits discussing water infiltration issues. In many of these cases, chemical sealing of the surface soil has occurred. This creates a crust that reduces the movement of the water into the soil. In subsequent irrigation, when water is applied faster than the rate of infiltration, puddling occurs, leading to an increase in evaporation as well as saturated soil conditions. This impacts water use efficiency and tree health. A season of irrigation can require between 36 and 52 inches of applied water per acre. This is often applied to a limited area of an orchard, which is defined as the wetting pattern. Each irrigation system has a different wetting pattern, with micro-sprinklers somewhere around 30-60% of the orchard area, and drip around 20%. This means that, dependent on the system, the wetted area may receive 2-5 times more water than the targeted season’s application per acre. In other words, if  four acre feet/acre were applied using a drip system that wets around 20% of the orchard floor, the soil in that wetting profile has nearly 20 acre feet of water that must pass through in order to infiltrate the soil. This is a tremendous volume of water to pass through the soil, and it can leach away beneficial elements which leads to chemical sealing and infiltration problems. When infiltration rates slow, it is important to know the causes as not all infiltration issues are the same. Taking an analysis of the water and soil is a good place to start. Unlike soil sampling conducted in the fall, soil sampling of the top 2-3″ of soil should occur to identify the chemical imbalance.  Analyzing the soil and water will give an idea of salt load, SAR, pH, as well as other elements. This will help identify

June 16, 2016

Role of Winter Sanitation for Navel Orangeworm Management

Written by: Jhalendra Rijal, Area IPM Advisor, UC-Cooperative Extension (San Joaquin, Stanislaus, Merced) Navel Orangeworm (NOW) is a primary pest of almonds, pistachios, and walnuts, with other significant crops hosts such as fig, citrus, pomegranates. This pest was first introduced in southern California in 1942 potentially from Central and/or South America. Because of the wide host range, this pest was quickly spread to the entire Central Valley within 5-7 years of its first introduction, established and had become a major production threat in almond and other nut crop production. Adults are greyish-brown moths (about ½ inch long) with grey markings on wings. Eggs are laid in mummy nuts or in the nuts with initiation of hull-split. Tiny first instar larvae bore into the nutmeat and all stages of larva feed on nuts producing large amount of webbing and feces (i.e. frass). Larvae are white to pink with a reddish-brown head, and with a typical crescent-shaped markings on the second segment of the body just behind the head. The mature larvae (5th instar) can grow upto ¾ inch in size. Besides direct damage on nuts, NOW larval damage can lead to fungal infections, such as the mold that produces aflatoxin, known to cause carcinogenic and mutagenic effects on human. The larvae overwintered in mummy nuts that are in trees or on the ground. Among non-chemical ways of reducing NOW populations or damage include early harvest and winter mummy removal (i.e. sanitation).  Winter Sanitation of orchards during the winter is the most effective way to reduce the damage in upcoming season. Mummy nuts should be removed from the trees before bud swelling stage (late January/early Feb.) by shaking the trees or by hand polling. The nuts should then be destroyed on the orchard floor by discing or flail mowing by March 15. UC IPM

December 22, 2015

Understanding and Applying Information from a Soil Test, Part 4: Boron, Chloride, Copper, Iron, Manganese, Molybdenum, Nickel, and Zinc

Allan Fulton, UC Farm Advisor, Tehama County and Roland D. Meyer, Extension Soil Specialist Emeritus This article (Part 4) discusses micronutrients and the use of soil tests to evaluate their levels in orchard soils.  Micronutrients are essential to almonds and other nut crops, yet are required in much smaller amounts than macronutrients such as nitrogen (N), phosphorus (P) and potassium (K) or secondary nutrients  such as calcium (Ca), magnesium (Mg), or sulfur (S).  The eight micronutrients are boron (B), chloride (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), and zinc (Zn).  They fulfill important roles in the plant.  For instance, zinc is needed for plant cell expansion and it influences pollen development, flower bud differentiation, and fruit set while boron is a building block for the plant cell wall and strongly influences pollen tube germination and growth.  Flower abortion in almond and walnut has occasionally been associated with boron deficiency.  Nickel has recently been determined to be an essential nutrient and there are no known deficiencies in California. Zinc, iron and manganese deficiencies are not as commonly found in the Sacramento Valley as in the San Joaquin Valley.  Zinc deficiency is most common in almond and other nut crops.  Other micronutrient deficiencies that are occasionally seen in almond include B, Fe, and Mn.  Copper (Cu), Mo, and Ni deficiencies have not been documented in almonds; however, Cu deficiency is common in pistachios. Five of the micronutrients (Cu, Fe, Mn, Ni, and Zn) largely exist in the soil as positively charged metal cations bound as minerals or adsorbed to the surfaces of colloids or soil particles.  Several factors in orchard soils may affect the solubility and availability of these metal cations to trees.  Soil pH greater than 7.5 has the major influence of reducing the tree availability of

November 6, 2015