California Almonds: Nut Fill Well Underway, Crop Size Still Impresses – AgFax

    Almonds after rain. ©Sara Savary, AgFax Media

    • Here is this week’s issue of AgFax Tree Crops.
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    Owen Taylor, Editor
    Jenny Holtermann, Contributing Editor


    Almond nut fill is well underway through a big part of the Central Valley. Yield potential continues to look strong.

    Temperatures generally cooled down in parts of our coverage area over the last week.

    Tissue diseases, while sporadic, have developed in wetter areas, and fungicides have been going out where warranted.

    Mummy sprays have been underway, mainly where sanitation didn’t happen or where efforts fell short.

    Delayed leafout remains an obvious factor in certain orchards. In places, trees seem to be filling in the gaps. This is occurring in both almonds and other crops.

    Bug populations this month have required treatments on what seems like a wider basis than usual.

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    Dale Deshane, PCA, Supervised Control, Bakersfield

    “The biggest issue in almonds right now is alternaria. It has been increasing in a good percentage of blocks, warranting a second treatment. Blocks we don’t usually see alternaria in are showing signs of it this week.

    “It is still early in the growing season, so we could end up with defoliation by harvest. Alternaria defoliation causes more of a concern for next year’s crop. If we lose foliage during the growing season, it can push premature new leaf development and take energy away from next year’s crop set.

    “This flareup in alternaria seems connected to last month’s wet weather and that week-long rain 3 to 4 weeks ago.

    “We are finding moderate amounts of rust in more blocks than we would like to see, although it doesn’t seem to have taken off too badly anywhere. Large amounts of botrytis developed during the last rainstorm. It dried up after damage.

    “We only made mummy sprays on 600 to 700 acres that had excess mummies left over from sub-par sanitation.

    “We see more leaffooted plant bug this year than I have found in 15 years. We have been treating and researching the cause. This year’s mild winter could have played a role.

    “Mites are still holding, and we have yet to detect an increase. Where we treated blocks for alternaria, we included a miticide as a preventive.

    “We’re finishing fertilizer applications in almonds.

    “In pistachios, we’re seeing botrytis in 40% of the orchards in our area. We’re even finding it in young 6- to 8-year-old trees. In areas with a history of alternaria, pistachio growers are treating with fungicides if they are already applying a nutrient spray. 

    “Mealybug treatment are being made in areas where damage occurred in the past and where crawlers appeared this year. There are three different materials we can rotate based on historical pressure and damage.

    “We still see the delayed leafout in pistachios and have yet to see buds developing. The problem is mostly in Golden Hills, but we’re also finding it in male Kerman trees.

    “Cotton growers just started mite sprays this week. Growers have been applying herbicides and are now adding a miticide. Cotton stands came up fast and look healthy. Planting was later than normal due to the weather, but cotton will catch up as heat units increase.”


    Gary Gliddon, PCA, Treevine Consulting, Modesto

    “One orchard on the west side had heavy leaffooted bug infestation, and we finished spraying a couple of days ago.

    “May mummy sprays only went out on a few orchards. In most cases, we didn’t see mummies, and growers decided not to spray. Navel orangeworm moths are flying around, but they aren’t attracted to green nuts.

    “Usually by this time, we see more brown almond mite damage. Rarely, if ever, do we find pacific mites in any numbers at this point. In a few orchards, we have seen colonies, but in most cases the beneficials are taking care of those populations.

    “Almonds are looking good and are beginning to fill out and solidify. Growers should remember to stay up on top of their fertilizer programs.

    “In walnuts, we are finding more codling moths compared to last year. High counts turned up in Chandlers, and most growers treated for the first codling moth flight. They had the option of applying a material for botryosphaeria at the same time.

    “After moths hit green nuts before they harden, those nuts will eventually drop, but it will be a few more weeks before we can assess that damage.”


    Brian Gogue, PCA, Helena Agri-Enterprises, LLC, Hanford

    “Pest issues are increasing in almonds. We did spray a few fields for leaffooted plant bug after we saw strike penetration and nuts on the ground.

    “Independence trees are showing something physiological – sap coming from the suture area of the nut – and this is happening in all of my Independence blocks. We have not detected any penetration damage in these instances.

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    “We are finding mite populations in a few blocks. In one block, we saw a decent amount of damage along a dusty end row, and we were able to make a border spray. We found small amounts of mites on a couple of other ranches. Overall, though, we haven’t had considerable mite pressure this year.

    “Over the next week, growers will be applying the last of their nitrogen for the season. Areas that are deficient will receive one more potash application.

    “All but a few growers made a mummy spray. Adult counts were high, and a few orchards had high egg counts, as well. Navel orangeworm populations were sporadic, and we saw a decline after we sprayed.

    “Almond development is progressing. Nonpareil is almost 100% filled in, and pollinators range from 50% to 75% filled.

    “Overall, this has been a light bug year in pistachios, and we haven’t had to treat any blocks for true bugs. Starting this weekend, we will make mealybug sprays where needed. They are approaching the crawler stage, which is the most effective time to treat the next generation. These treatments overlap with the hatch of frosted scale, so we’re able to make one application for both.

    “Fertility is going strong and trees look healthy.

    “Walnut growers completed their first round of fertilizer applications over the last two to three weeks. They will apply another round in two to four weeks. The Serr crop is the biggest we have seen in a long time. Tulare and Chandler are sizing up excellently, as well. A big crop will be great for growers because the price has been unstable lately.

    “Cotton is growing well, and we’re mainly treating for weeds. Acreage is way down this year between price and the water situation. Growers delayed planting due to the late rains.

    “Tomato growers are cleaning up thrips in most blocks. Leafhopper pressure is minimal. Early bloom and crop set look good. Weeds are an issue, and chopping crews have been moving through fields. Powdery mildew is showing in early blocks and treatment has started. Fertility is in full swing, as well.

    “Grapes are post-bloom with no signs of mildew.”


    Franz Niederholzer, UC Farm Advisor, Colusa, Sutter and Yuba Counties

    “Scattered showers fell across the Sacramento Valley early this week, with totals from less than a tenth of an inch to a half-inch. Cloudy skies and variable rain are in the forecast for this weekend (5/16-17) and into Tuesday. The rest of the month looks seasonably cool with no heat waves in the long-range forecast.

    “Sprayers are applying fungicides in almonds if they didn’t already go out last weekend. With this rain forecast, the main concerns are summer diseases like rust and anthracnose. Scab and alternaria also are concerns on ranches with a history of diseases, although I haven’t seen any significant issues yet.

    “Navel orangeworm egg counts are as expected. We’ve found them in some traps every week since late April. However, we do not see them in every trap every week. Growers who decided on a May spray for NOW this week may be combining it with their fungicide sprays. Timing can be tricky since the flight lasts far longer than any insecticide does.

    “The almond crop looks tremendous and nuts are well into kernel fill. We are in the final stretch for nitrogen applications. Maintaining adequate potassium in the orchard will be essential for delivering a good crop next year, given the large 2020 harvest. Almonds use potassium up to hull spilt, so we still have time to make an application if spring leaf samples show lower-than-acceptable potassium levels. Orchards deficient in potassium this year will produce fewer flowers next February.

    “Monitor moisture to ensure you’re matching irrigation to the orchard’s water needs. Predicted orchard water use for the coming week is 85% of normal and last week’s ET numbers were normal or just under it. Assume that only 50% of rainfall actually is available to the plants. ET values for all tree crops in both north and south Sacramento Valley are available on line.

    “Also, sample irrigation water for water quality issues like salinity, chloride, boron and bicarbonates.

    “Between the rain last weekend and what’s in the forecast this weekend, walnuts could be set up for walnut blight and botryosphaeria infections – if a bactericide for blight or a fungicide for botryosphaeria haven’t been applied.

    “The walnut crop I’ve seen looks good, with doubles and some triples. We are approaching the first nitrogen application. Husk fly traps can begin going in place on June 1.

    “Growers have been shaker-thinning prunes. Rust can be a concern for prunes, so consider applying a rust-control material.”


    Sara Savary, PCA, Crop Care Associates, Fresno

    “In almonds, growers are slowly finishing treatments for leaffooted plant bug and stink bug. The damage kept increasing every week in individual blocks, which warranted a spray. Stink bug damage turned up more in blocks near alfalfa fields. We found the first leaffooted bugs in blocks close to riparian areas.

    “Growers who were spraying navel orangeworms included a material for leaffooted bug where needed. My growers didn’t do mummy sprays because they tend to control them pretty well with mummy shaking and sanitation.

    “The high temperatures last week helped increase our degree days and didn’t seem to chase away the beneficials. We did see a slowdown in mite activity. Where we were finding mites, we also found beneficials.

    “Alternaria always develops in a few of our blocks, and we will apply a fungicide in those cases. Along with a history of pressure, these tend to be orchards with dense canopies and sprinklers.

    “We detected downy mildew in one walnut block and will continue to monitor that.

    “The codling moths’ first hatch and flight, the 1A, started last week and continued into this week. Next week, we expect another hatch and flight, the 1B. Ivanhoe and Tulare tend to be more susceptible to the first flight, and we sprayed last week. Chandlers don’t seem to warrant a spray until the second flight. We did find a more noticeable drop with last week’s warmer temperatures.

    “Peach harvest started in the early varieties, and that will transition into the white peaches next. Grapes are halfway done with bloom, depending on varieties. Growers are applying gibberellic acid to thin the bunches and adjust the berry size.”


    Rodney Ratzlaff, PCA/CCA, Nutrien, Merced

    “Weather seems to be on a roller coaster ride, with some temperatures this last weekend nearing 100, then this weekend (5/16-17), the forecast calls for highs in the 70s and the possibility of a few rain showers on Sunday to Tuesday.

    “Except for a couple of days with extreme heat, the weather has been fair for new growth, and most of the trees I’m looking at are growing well despite the large crop. I’m measuring anywhere from 8 inches of new growth to well over a foot of it.

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    “We are wrapping up nitrogen usage in a couple of weeks, accounting for total usage so far, and preparing for the final amounts needed. This is also a great time of the year to grab some tissues and treat specific nutrient deficiencies before the trees start bud differentiation.

    “The almond meat is starting to solidify, making the next few weeks the heaviest the nuts will be throughout the year. That load will continue breaking branches, which seems to be happening all over the valley.

    “Pest pressure remains light in our area. A couple of my growers treated for leaffooted bugs and were able to combine that with a miticide. For the majority of my growers, the May sprays went out, as well. Mites are still mostly hard to find, but I expect pressure to ramp up.”


    Luke Milliron, Area Sustainable Orchard Research Advisor, Butte, Glenn and Tehama Counties

    “The National Weather Service forecasts 1.5 inches of rain in Chico over this weekend and into Monday. This will be a warm storm that is friendly to fungal pathogens. Temperatures aren’t expected to dip much below 70, then ramp up gradually.

    “Almonds continue to adjust their crop load, but the crop continues to look excellent, overall. Hopefully, growers did not fall too far behind in nitrogen and potassium levels with the tremendous crop the trees are carrying. Ideally, nitrogen programs wrap up in May.

    “At our northern trial site where we’re looking at delayed irrigation, the irrigation has been turned on for a couple of weeks for all treatment. The delayed treatments have recovered well from the moderate water stress we induced. Hopefully, with growers in the swing of their regular irrigation, they are waiting to irrigate until the trees are -2 to -4 bars below the fully watered baseline.

    “Other people have reported leafout issues in almonds. We also are seeing that in other crops, including walnuts. Some blocks had a ‘poodle tail’ appearance at the treetops a couple of weeks ago, but they are starting to fill in. I also have observed some possible winter kill, potentially dating back to freezing temperatures in November. I have only seen this suspected freeze damage in blocks that also exhibited freeze damage last year from the November 2018 freeze event. This doesn’t appear to be widespread.

    “Some PCAs are continuing to see high codling moth counts. Many sprayed in the last week or two. Some PCAs are now at the 1B flight timing, while others estimate that they are between 1A and 1B.

    “With walnut blight, yield loss is generally prevented by the first two to three spray timings. However, infection from storms in May causes secondary infections. Although secondary infections don’t reduce yield, they can lead to mold problems late in the season and create an early entry point for navel orangeworm.

    “Fruit-set counts in prunes, made by UC farm advisors, show very low set in some orchards in Sutter where orchards had temperatures peaking at 83 during full bloom. In other parts of the Sacramento Valley, temperatures generally didn’t exceed 81 at full bloom, and many growers have enough of a crop to warrant shaker thinning. Growers are reporting highly variable crop set between neighboring orchards as well as within orchards.

    “Many walnut growers have been irrigating since the end of April or started earlier this month. But as far as I could tell, the trees weren’t under measurable water stress at the time. In a Yuba City trial site, the trees were at -2 to -3 bars below the baseline level earlier this week. However, with the storm this weekend, they will continue to hold off on starting regular irrigation.

    “In a trial in Tehama over several years, we delayed starting irrigation until trees were -2 or -3 bars below baseline. Those trees were actually less water-stressed in October compared to trees irrigated starting in April.”

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