California Almonds: A Large Potential Crop Continues To Shape Up – AgFax Tree Crops

    Photo: Almond Board of California

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


    Temperatures trended slightly warmer following the large storm that ended last weekend (4/11-12) across the southern valley. Small amounts of rain were in the forecast this weekend through the Central Valley. Another warm-up is in the forecast.

    Insect pressure remains mostly minimal across our coverage area. Unseasonable rain totals to date are likely suppressing activity.

    A large potential crop – that continues to be the consensus observation from our contacts. So, it will be necessary to stay on top of fertilizer programs. Leaf sampling and regular crop monitoring will be essential. 

    People in the field are beginning to plan May sprays to stay ahead of navel orangeworm.

    Frosted scale is showing up in pistachios in several areas. Growers tend to treat with winter dormant applications if needed, but foliar treatments are being made in places this month.

    Walnut bloom has been underway, with blight sprays going out where needed.

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    Sara Savary, PCA, Crop Care Associates, Fresno

    “It has been a beautiful time of year in the orchards, and you can start seeing the almonds growing and sizing up. After a fresh rain, the orchards are green and gorgeous.

    “The rain last week helped keep mites down, although at some point the rain does become a hassle with controlling weeds. Weeds continue to grow, and growers can’t spray as needed because the ground is too wet. By the time a few growers were able to spray, we had to increase herbicide rates because weeds were larger by then.

    “All my growers were able to apply fungicides before last week’s storm, and we don’t see any disease issues of concern yet.

    “Almond brown mite is showing up sporadically, and it tends to be a problem when the weather is cooler. When temperatures heat up, the brown mite tends to go away. We will continue monitoring it through late May and see if they start causing enough problems to justify a spray.

    “Leaffooted bugs turned up in a block in Fowler next to a citrus grove. Their activity could be starting up more due to rain. Based on our first peach twig borer biofix, we expect the first hatch to start in the second week of May.

    “Green stink bug is showing up intermittently in an area near Firebaugh with a history of populations. We will monitor and spray if they build.

    “Navel orangeworm pheromone trap counts are starting to go up, and they generally peak towards the end of April. We will continue watching their flight. Our area doesn’t have a significant history of navel orangeworm, and most growers did a good job with mummy shake removal.

    “Fertilizer programs are a third of the way through, and we expect to wrap up applications by mid-June. The tissue sample results are mostly on track. We have pinpointed a few blocks that are low on nitrogen, and we will increase the rate in the next rounds. We also spotted a few orchards low on copper, which we’ll add to the micro-sprinklers in the following irrigation. We generally recommend saving a small amount of the nitrogen program for hull split to aid in next year’s bud development.

    “Growers who rushed to apply zinc too close to the last rainstorm ended up burning the tips of some leaves.

    “Walnut growers just completed blight spraying in areas with concern. The early varieties finished blooming. We have not seen codling moth in traps as of yet.

    “In tangerines, we’ve been applying gibberellic acid to keep fruit from dropping. Stonefruit growers have been thinning orchards. Spraying has wrapped up for katydids, which bite the developing nectarine and can scar the fruit as it grows.”


    Dale Deshane, PCA, Supervised Control, Bakersfield

    “We’ve had a nice change of pace this week, with a high of 87 degrees this afternoon (4/16). Last week, it rained over 4 inches in some areas from the storm Sunday (4/5) through Thursday. Next week, the forecasts for Monday and Tuesday show a 40% chance of scattered showers, with possible amounts from a tenth of an inch to an inch.

    “Following last week’s storm, we see green fruit rot in places. The nut turned mushy and is just rotting.

    “The ground was too wet for too long, and we are starting to see botrytis issues in areas. A lot of little spurs at the top of branches are dying off and appear burned.

    “We’re seeing signs of rust increasing, so that could be a threat. We are monitoring for mites, but they haven’t taken off in large numbers yet.

    “One grower is treating for plant bugs, and populations are starting to increase. If temperatures get warmer, those numbers might build.

    “High numbers of stink bug developed in hay fields this year. After the rain, we do not see migrations following freshly cut fields.

    “We are detecting low navel orangeworm numbers for this time of year. Pheromone traps in almond orchards with high mummy counts have not shown high numbers at this time. How we approach May sprays this year has yet to be determined.

    “Botrytis and botryosphaeria are concerns in pistachio orchards. We see spotting in foliage due to the rain.

    “We are finding frosted scale this year in pistachios. Most growers treat for frosted scale during over-winter dormancy. Last year, pressure was low and we didn’t treat. Other growers have been able to add a treatment to other applications and gain control.

    “In pistachios, navel orangeworm numbers are running low. Egg counts have been high, with 100-plus in one trap through the week. The higher numbers appear to be in fields that lacked sanitation measures.

    “Applying fertilizer has been a challenge due to rain. Some growers have applied very little fertilizer, while others are halfway done.

     “Growers are trying to gear up for planting cotton. They were unable to get in before the big rainstorm. If they aren’t able to get in before the end of April, growers might end up not planting cotton.”


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

    “Weather has been good, with highs in the upper 70s to low 80s. We have a chance of rain this coming Sunday and Monday (4/19-20), but forecasters are backing off on amounts, so it’s hard to tell if any fungicide treatments are needed.

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    “We are at 108 degree-days for navel orangeworm as of early this week at the Nickels Soil Lab. Peach twig borer trap counts are increasing this week from the low, spotty numbers we’ve had since mid-March.

    “An experienced PCA found many adult leaffooted plant bugs in an orchard in Glenn County next to a pomegranate orchard. We need to carefully monitor for this insect, especially near pomegranates or any evergreen landscape. It’s a spotty pest but can damage the crop where populations build.

    “We’re feeding a heavy crop this year, and many growers have already finished applying up to half of their annual nitrogen budget. If you’ve got a heavy crop, don’t fall behind on potassium. Spring leaf sampling can help growers avoid potassium deficiency at summer leaf sampling. Leaf K running less than 1% can limit production next year.”


    Gary Gliddon, PCA, Treevine Consulting, Modesto

    “Over the past two days, we’ve walked 2,000-plus acres, and they are currently disease-free and setting a good crop.

    “The big storm last week brought cooler temperatures, down in the 60s. Growers were at the tail end of their fungicide coverage, and I don’t foresee any problems with diseases like anthracnose and rust. Both prefer warmer temperatures. Warmer storms with significant rain would be a different situation, which would warrant another fungicide. 

    “As the crop sizes, this is a year to stay closely engaged with your fertilizer programs. Programs vary, depending on the size of the crop and fertilizer ratios. Growers are roughly a third of the way through their fertilizer programs and are on track to wrap them up by June 1. 

    “Almond trees perked up after the rain last week. We have seen increases in water penetration with rain versus irrigation.

    “Peach twig borer started making an appearance Wednesday (4/15), and navel orangeworm egg trap counts are beginning to trend upward.

    “Obliquebanded leaf roller (OBLR) numbers were slightly heavier this year. OBLR is now getting into the nuts, but the nuts will fall off once infested. The tree compensates for the loss, which is hardly a pound or two per acre. The next generation, which comes later, will get into the hulls but rarely into the nuts. They are usually not a factor for rejects.

    “We started spotting codling moths yesterday in walnuts. Codling moths usually appear the first of April or even around the end of March in some years. Moths might be showing up later as they adapt to later walnut varieties.

    “Chandler is just leafing out and showing leaf clusters and small nutlets. One grower is applying a blight spray on Chandlers now ahead of the upcoming storm. No growers made an application prior to the rain last week.


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

    “The forecast shows a 40% chance for a tenth of an inch of rain over the weekend (4/18-19). Last week’s storm brought from four-tenths to over an inch. Winds from that system were concerning. I’ve seen some degree of loss in every orchard, with significant but variable damage in places.

    “Where we went with mating disruption last year, we are seeing minimal navel orangeworm numbers in traps this year. Weekly trap counts vary from zero in places to as high as 40 to 50 moths over a week in some locations. The rapid change from cold weather to warm weather could be playing a role. May sprays will begin in about 10 days.

    “With all the rain, it’s been challenging to apply fertilizers. Growers are now applying nitrogen and potassium and hope to catch up. We pulled all of our tissue samples this week. The crop size looks ‘average-plus’ and the nuts look larger than average.

    “Pistachio bloom has wrapped up in most blocks. Some Kermans are at about 80% bloom. On the early Golden Hills orchards, we were able to apply a few fungicides and foliar sprays before the rain last week. After the rain stopped, we completed the remaining applications.

    “A Kerman orchard in Huron had minimal bloom last week, but this week it was at 100% bloom. The prior week, the males were way behind, but they very quickly caught up. Warmer temperatures helped, but they still moved faster than usual.

    “Our earliest Golden Hills have a lot of leaves out and green showing. 

    “Frosted scale is showing more than usual this year. Pressure appears to come and go, depending on the year. Growers tend to treat with winter dormant applications, if needed.

    “Grapes are developing well. Bloom in the earliest varieties will start in 7 to 10 days.

    “Due to the rain, tomato growers made a few fungicide applications, mostly preventive sprays. Tomatoes put on a lot of growth in the last week. We will continue to monitor for leafhopper and thrips. We will plan on foliar sprays to control leafhopper populations, mostly with systemics through drip irrigation.

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    “Chopping weeds has started in tomatoes. Fertilizer is going out now, too –nitrogen, phosphate and zinc at this point.

    “The first cotton went into the ground earlier this week. Cotton acreage will be down very significantly this year. With water allocations and low cotton prices, grower returns are not justifiable this year.”

    Rodney Ratzlaff, PCA/CCA, Nutrien, Merced

    “Despite some recent rainfall over the last couple of weeks, things have been quiet in the almonds. The crop looks incredible, even though the next nut drop is right around the corner. In the clusters, you can see what’s undersized and that most likely won’t make it past May.

    “We’re scheduling regular irrigations. It appears the rain had relatively little effect on soil moisture, based on our checking. We are developing plans for the May spray to get ahead of navel orangeworm and mites, even though pressure has been minimal.

    “I have still not been able to find any plant bugs this year, even in areas where I regularly saw them in previous years. Time will tell if this stacks up to be a significant pest year, as previously predicted.

    “I would suspect that foliar diseases will start showing now with the weather warming into the high 70s and low 80s, plus some dew in the mornings. Preventive scab sprays went on with pressure in the 5-week post petal fall spray.

    “Nutsedge is popping up in just about every orchard that allows enough light penetration. Fertilizer through the water is staying steady, with April and May being big months for nitrogen and potassium usage.”


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

    “Following the rain in the last few weeks, we are just getting into drier conditions in the fields.

    “In an almond irrigation research plot, we are evaluating tree water stress and analyzing when to start regular irrigation. In trials in Tehama and Stanislaus Counties, we are evaluating with pressure chambers rather than soil moisture or ET to gauge when irrigation should begin. In studies, it has shown the detrimental effects to the root zone of early irrigation and wet springs.

    “Prunes are starting to size up, and I’m hearing mixed reports about crop set in the Sacramento Valley. A flash bloom, combined with multiple hours above 81 degrees around full bloom, can lead to poor set. Localized spots may have taken a hit from this.

    “For growers with a good set, prepare to thin around reference date in order to deliver large fruit. Reference date is typically a week after the pit tip begins to harden. For more information, see our thinning calculator.

     “Walnut leafout is progressing. Blight risk has increased with recent storms in certain areas. Blight tends to take a while to develop. Assess damage severity as it progresses.”

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