David Doll0 commentsApril 8, 2016General

2016 Mid-Spring Update

The crop is developing nicely in many areas across the areas of the San Joaquin Valley in which I observed. Crop loads vary, depending on last season’s stress or crop-load, but generally look good. Looking forward to this week, there area few pointers to keep in mind. Rain is forecasted for this weekend with chances through next week. This will have minimal impacts on the physiological development of the crop. It will, however, impact the amount rates of evapotranspiration and soil moisture. This variance should be accounted for by either using soil moisture monitors or plant based measurements. If possible, rain gauges (or other measurement tool) should be placed at the various farms as rainfalls can be variable. Last year, for example, a thunder cell dropped around 3/4″ of rain in a farmer’s field on the North side of Livingston, while his block on the south side received less than 1/4.” Accounting for these differences can prevent the “stalling-out” of growth from over-irrigation. Even though it warmed up this week, it might be wise to question the start of the irrigation season. Only two out of four plots in which we are measuring stem water potential have indicated the need to irrigate. The other two are still reading around baseline…one is even in a Delhi sand. Plant based measurements should be used to help determine the need to irrigate. Remember: the tree is essentially a giant tensiometer with a lot larger volume of soil impacting the result. Disease update: Multiple days of rain are predicted. This could mean conditions suitable for Bacterial Spot (especially on ‘Fritz’ and ‘Padre’), Anthracnose (for ‘Monterey’), Scab, and Shot-hole. Lingering infections of green fruit rot may also progress. If a treatment is warranted, check the fungicide efficacy table. Remember to rotate away from the last spray

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David Doll0 commentsDecember 31, 2015General

2015 Top Ten Articles

In maintaining the tradition of counting down the end of the year, below are the top ten articles read in 2015 from the readers of “The Almond Doctor.” 10: It’s the Nut Price, Dummy. A great article by Franz Niederholzer that discusses the rationale behind the increased plantings. It was the number one read article in 2013, number 3 in 2014. 9: Leaffooted Bug Advisory for Almonds: Two of our IPM advisors, Kris Tollerup and David Haviland, provided an advisory for Leaffooted Plant Bug after the mild conditions of the 2014-2015 winter reduced insect mortality. 8: Almond Bloom 2015: General considerations for various concerns at bloom. An annual topic during a time of year with highly variable conditions. 7: Understanding and Applying Information from a Soil Test, Part 2: A part of a series of articles discussing soil nutrients as determined through a soil analysis written by Allan Fulton. 6: Proper Almond Tree Planting: An excellent article written by Brent Holtz discussing proper tree planting methods. Considering the number of new plantings in 2015, the article finding its way into the top 10 isn’t too surprising. 5: Drought Management for Almond: Drought was a major challenge for many operations in 2015. This article discusses strategies to help reduce the impacts of water stress and drought. 4: The Seasonal Patterns of Almond Development: Back from the dead, this 2009 article picked up over 1700 reads which may be due to the increase of almonds in the media. It covers the general biology of the tree and stages through the year. 3: More Leaves than Flowers: Why? : This past year, in many orchards, flower density was lower than normal, and trees pushed more leaves earlier than in the season. Issues from 2014 had a carry-over effect into 2015, and this article explains a few

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David Doll12 CommentsOctober 26, 2015General

Kaolin Clay May be Useful in Increasing Chill Accumulation in Pistachios

David Doll, University of California Cooperative Extension, Merced, CA; Clay Beck and Joe Coelho, Valley Orchard Management, Three Rocks, CA. A preliminary study conducted by the University of California Cooperative Extension and Valley Orchard Management in which Surround® was sprayed onto dormant pistachio trees has shown an increase in cluster count and yield. This technique may be useful in increasing chill unit accumulation by 5-7 portions in winters with minimal fog and high amounts of sunshine. Over the past two years, pistachio orchards have shown classic low chill symptoms, which include weak, delayed, and protracted bloom, poor overlap with males, and weak leaf-out. This can lead to a severe reduction in yield due and high blanking due to poor pollination. Chill is weather related and a function of temperature and time. In cool, cloudy weather, chill portions accumulate quickly as temperatures stay within the ideal range of 33° and 54°F. When temperatures are below or above this range, chill units do not accumulate and could be subtracted if the temperatures are too high. This means that during warm, sunny weather during tree dormancy, chill portions do not accumulate, and if too warm of weather, negation of earlier accumulated chill occurs (For more information please see: https://thealmonddoctor.com/2015/01/13/chill_portions_model/). Chill units are calculated using ambient air temperatures. This may be inaccurate, however, due to the temperature of the wood. In sunny weather, wood is usually warmer than the ambient air temperature due to radiant heat, while in cloudy weather, the wood temperature matches ambient air temperature. With this consideration, sunny weather may increase wood temperatures above the ideal range, negatively impacting the accumulation of chill. In attempts to increase chill unit accumulation in the winter of 2014-2015, several applications of Kaolin clay (Surround®) were made to a ‘Kerman’ with ‘Peters’ pistachio orchard located

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David Doll8 CommentsOctober 25, 2015General, Horticulture

Planning and Planting a New Almond Orchard

When planning a new orchard, it is important to consider location, water availability and quality, irrigation system selection, pre-plant soil modification, rootstock, and variety selection. Mistakes made during the planning process will be present throughout the orchard’s life. Below are some considerations to keep in mind when selecting a site, rootstock, and variety. Site selection and modification. Soil type. Soils that have a high water holding content can be problematic when trying to access the orchard in early spring. Furthermore, these soils may also increase the risk of “wet feet” and Phytophthora infections. Rocky soils can make  orchard operations like harvesting and mowing challenging, but generally can be managed unless it is more rocks than soil.  Saline-alkaline soils will have challenges with water infiltration. These soils often require pre-plant leaching or modification to leach salts. Salinity. Soil salinity should be below1.5 dS/m as an average of the rooting depth (five feet). To determine the salt levels, soil samples should be collected from each of the differing soil types in the field.. Sample plugs or auger cores of each soil type in 4-5 locations. At each location, sample every 12 in of depth to 60 in. Combine and pool samples at a given depth (e.g. combine and mix 4-5 samples at 12 in depth, 4-5 samples at 24 in depth etc).   A composite sample should be pulled for every 20 acres, with a minimum of three samples for smaller fields. Nematodes. When soil sampling for salinity and soil nutrients, set aside some of the soil  from the 12-24”   depth samples for nematode analysis. Submit the soil to a lab that can test for nematodes. For almond and other stonefruit, nematodes of concern are ring, root lesion, and rootknot. If counts are greater than 50 per liter (or 500 grams) of soil

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David Doll0 commentsAugust 1, 2015General

2015 Harvest Time Updates

Over the past week, a few interesting observations have been made. These include: 1. Hull rot in Nonpareil appears worse in many ‘Nonpareil’ orchards. This is most likely due to the higher-than-normal humidity levels experienced during the initiation of hull-split. Most of the hull rot appears to be from the black bread mold Rhizopus. The dieback being observed is from the translocation of the toxin back into the limb. This often causes gumming which can reduce the ability to remove nuts during shaking. Applying a fungicide now will not cure the infections or prevent the movement of the toxin. 2. There have been several reports of Fuller Rose Beetles clogging micro-sprinklers. These insects lay a mass of eggs in the opening of the sprinklers, reducing water flow. Surprisingly, reports are even coming from growers who have switched to pop-up micro-sprinklers, which are considered more resistant to clogging. This nocturnal beetle has one generation per year with most of the adult activity occurring in August – October. The beetle needs to feed on leaves for a few weeks prior to laying eggs. Although chemigation of the soil is not effective for controlling the insect or eggs, there is some thought that treating the trunks with a registered broad spectrum insecticide may kill the beetle as it migrates from the soil to the trunk. If attempting this strategy, be wary of the PHI of the product you are planning to use. More information can be found in this presentation and at the UC IPM website (You may need to look under a different crop). Keep in mind that the best long-term management of this pest has been through the use of clog resistant, pop-up type microsprinklers. 3. Reports of gummy kernels from boron deficiency and stuck nuts from boron toxicity. Gummy kernels that occur may

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David Doll0 commentsMay 8, 2015General

2015 Mid-Spring Updates

A lot of excitement this past week with the passing storms. Some large thunderstorms passed through Merced Co. dropping some hail and rain. As with any thunderstorms, rainfall totals vary. A few calls have yielded some concerns which are highlighted below. 1. Irrigation for areas with low rainfall totals will most likely still be needed. Use is highly variable depending on the weather, but for the most part, a warm (>80F) sunny day will require 0.25″ of water/acre to maintain full irrigation for a mature block. Cloud cover and cooler temperatures can reduce demand by as much as 1/2. This is using an assumed Kc value of 1.00. 2. Ants. Fields should be scouted and, if needed, baits should be applied. Baits – since they are growth regulators- must be applied 1 month prior to harvest for maximum effectiveness.  Be mindful that not all ants present within the orchard feed on almonds. A quick trick to distinguish “good ants” from “bad ants” is to throw potato chips or a hot dog near the mound. If consumed, it can be assumed that the colony will also feed on almond kernels. Another trick is to  stomp near the mound to bring ants to the surface. If they swarm out of the mound, are red in color with a black butt and bite, they are mostly likely fire ants. Monitoring and treatment information can be found on this previous post and at the UC IPM Website . Ants often cause more damage than expected. High populations can consume between 1-2% of the crop within four days. 3. Hail damage. Hail can cause crop loss as it knocks nuts and new growth form the trees. Nuts that are “bruised” may fall 3-5 days after the damage occurred. If the nut remains on the tree, it will typically yield

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David Doll0 commentsApril 6, 2015General

Mid-Spring Considerations/Update

The 2015 almond season is in full swing. Many orchards have went through their drop, fertilizer applications and irrigation have began, and pest management concerns are beginning to form. Below are some thoughts and considerations from recent field visits. 1. Crop development is ahead of schedule – by as much as a month. Kernel fill is beginning in many ‘Nonpareil’ orchards, meaning that ‘Butte’/’Padre’ orchards won’t be far behind. This timing is important as about 80% of the season’s nitrogen budget should be applied prior to kernel fill – which may occur as early as early May! Secondly, it indicates that at this point – “What you see is what you’ll maximally get” in regards to kernel size, and farming practices – more particularly irrigation practices – can only reduce crop size. 2. Peach Twig Borer’s (PTB) “May Spray” timing looks to be an April timing. In the Merced area, our traps picked up a biofix around March 15th, which means we will be approaching 300 DD in about 7-10 days. Keep in mind that the spring spray timing for PTB is 300-400 degree days after the biofix. It may also be possible for the May Spray to have some effect on NOW.  Frank Zalom (UC Davis Entomologist) has found through research trials that timing the spray to 100 DD post NOW biofix (egg traps) and around 400 DD post PTB biofix can provide good control of NOW and PTB at harvest. 3. Rain is predicted for Tuesday (the 7th). Hopefully some rain will fall in the valley to help with the multitude of water issues. This rain may also bring some potential for fungal disease – especially rust and scab. Consider an application if there has been a history of disease. This application can be made 1-2 days after the rain event and

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David Doll9 CommentsJanuary 30, 2015General, Insects

Honey Bee Considerations at Bloom

There has been a lot of concern about honeybee health related to fungicide and insecticide applications within orchards. More is being learned every year about the impacts of pest management practices on hive health. Recently, The Almond Board of California released an excellent resource titled “Honey Bee Best Management Practices for California Almonds.” This resource provides an overview of the research conducted and the recommendations generated from the results and conclusions. The following is a brief overview of these practices that are associated with insect and disease control around bloom: Read the pesticide label carefully – including surfactants – and avoid any chemicals that indicate toxicity to bees. Avoid applying or tank mixing any insecticides during bloom until the effects on bees are known. Treatments for peach twig borer should be considered prior to bee move-in or after hive removal (i.e. delayed dormant, “May” spray); Avoid the fungicides iprodione, captan, or ziram. These fungicides negatively impact bee hive health; Apply fungicides later in the afternoon or evening when bees and pollen are less present. It is also important to also not spray too late that the fungicide does not have a chance to dry before the next foraging day; Addition of adjuvants is not needed unless specified by the fungicide label. These compounds may harm bees by increasing fungicide activity; Cover or remove the bees’ water source and avoid spraying the hive directly with any pesticides. More information can be found at The Almond Board of California. Keep in mind that these spray practices are independent of good bee hive care, which includes provision of water in during dry bloom periods, sources of pollen.nectar in bee holding areas, and of course, good communication with your beekeeper.

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David Doll0 commentsDecember 30, 2014General

2014 Top Ten Articles

Following a long standing tradition of developing a “Top 10” list to celebrate the old and bring in the new year, here is a quick review of the top ten articles read this past year from “The Almond Doctor.” 10. Water Stress, Early Hullsplit, and Kernel Size. Severe water stress from the drought caused an induced hull-split in some blocks across the state. This article explains the impact of this observed phenomenon.

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Franz Niederholzer1 CommentJune 14, 2014General

Thanks, and So Long, Gene

I said goodbye to an old friend this past weekend.  I will miss him.  He (and his family) taught me a lot about fruit growing, but I will remember him most for teaching me to be a better extension agent/advisor.  He told me what farmers knew and what they wanted to know.  He pointed out, in private, how something I said or wrote might be heard by or impact growers.  I called him when I needed advice on resolving conflicts between growers or growers and other community members that ended up on my doorstep.     

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