AMERICAN PISTACHIO GROWERS Member Luncheon INSIDE ANNUAL MEMBER LUNCHEON OCTOBER ORCHARD TIPS SEPTEMBER 2022
Pistachio Growers' Chair, Dennis Woods,
AMERICAN PISTACHIO GROWERS GATHER AT THE ANNUAL LUNCHEON July 29, 2022 – Visalia, CA APG MEMBERS GATHERED FOR THE ANNUAL MEMBER LUNCHEON IN VISALIA, ON JULY 29. APG STAFF WELCOMED OVER 300 ATTENDEES TO THE ANNUAL SUMMER GATHERING. American
opened the luncheon by welcoming everyone.
APG Ambassador Miss California 2022, Catherine Liang, who was crowned in June, kicked off the event by playing the national anthem on the piano.
Orchard Tipsfrom
wells and equipment still suffers from Covid recovery; labor is more expensive and seemingly less motivated; and water is scarcer, saltier and more expensive. Yields have also been less than expected for many growers. It is anybody’s educated guess as to why.
The guess gets more accurate when growers have simple, in-orchard weather recorders like Hobo® to provide data on chill portions and spring temperatures. This data proved extremely valuable to growers submitting crop insurance claims for the near-100 degree Fahrenheit temperatures on April 7 and 8, followed by temperatures ranging from 27 - 31 degrees Fahrenheit on April 12-13. As Craig Kallsen suggested in his “emergency alert” note on April 14, the impact of these events was not immediately evident, but surveys of orchards, shortly after, revealed that damage to fruit set was more widespread than expected. It would appear that the heat/cold events also “stressed” the trees, because fruit size is smaller this year in mature trees, even with only moderate crop levels.
I can only guess at what that “stress” was, but it may have been associated with the additional consumption of depleted stored carbohydrates (CHO) following canopy development as well as those produced by the leaves early in the season. Both the heat and cold events would have elevated respiration during a period of crop development at which the pool of carbohydrates was limited. Thus, even though temperatures following the heat/cold event were favorable to CHO synthesis, the pool was still insufficient to optimize shell expansion even under moderate crop load. From the grade sheets shared with me, the smaller nut size has certainly favored the split percentages when irrigation, during kernel fill (Stage 3), did not create yet another stress event. Please be reminded that the above is an educated GUESS at what might have happened. I welcome comments from deciduous trees stress physiologists. Let’s now review management tasks for October:
1. Get on the ATV and survey for gophers, nutritional deficiencies such as copper and zinc, trees whose crotches are split from shaking and require bolting and/or tying, and the position of crop left after shaking, which requires attention during pruning. The gophers have been terrible this year. Control with various effective tools improves once the soil is wetted. Hopefully the improvement will happen by early fall rain!!
2. Review your grade sheets carefully, and note the location of each load delivered. Make a simple summary sheet indicating the general location of the load, the percent of clean open inshell split nuts, the light stain, dark stain, percent closed shell and blanks. Also record the bonus received for stain and insect. This summary sheet proves very useful in identifying possible nutrition, irrigation, soil salinity, or pest management problems.
3. Meet with your soil consultant to arrange for sampling. I highly recommend including a 0-3 INCH sample of the surface soil in the area, which is routinely wetted from irrigation. Surface soils low in exchangeable calcium, high in sodium or bicarbonates, or affected by too low or high a pH are often masked with the routine 0-1 FOOT sample. The precious irrigation water applied during the critical stage 3 (kernel filling), may not be penetrating the soil surface because of mineral imbalances at the soil surface. Do not sample directly beneath drip emitters; constant wetting at the emitter site creates soil chemistry profiles that often do not reflect the bulk of the wetted area.
4. Leave your NOW Mating Disruption dispensers up until early November if your supplier says they are still capable of dispensing pheromone. This helps reduce NOW mating during the fall, and conceivably reduces the overwintering NOW population. Randomly collect 20 clusters remaining in the trees and crack out every nut. Record the percentages of split and infested nuts to guide your winter sanitation program. Some orchards may be so infested that lightly shaking them now could be justified. Disk or grind the removed nuts to destroy the NOW larva.
5. Review the condition of your tree canopies with someone knowledgeable about pruning. Discuss your options for side-hedging and topping versus hand-pruning. Determine what type of cuts would be required to maintain an efficient fruiting system.
6. Meet with your PCA to discuss the various weed spectrums present in your orchards. Agree on a program and get your materials ordered and delivered as soon as possible to avoid supply problems. Service your herbicide equipment to insure all the hoses are sound, the pressure gauges work, the nozzles are new and clean, and the pump is supplying the correct volume. Have a treatment plan in place with workers aware of their assignments so that you can act quickly to rain forecasts.
7. Get soil modification accomplished as quickly as possible, while the ground is dry and responds well to ripping or slipplowing. Berm now, if you plan to plant on them in the spring, so that you can reduce the weed population over the winter and have them settled by spring.
8. Irrigation should have stopped on newly planted orchards and those up to four years old by no later than mid-September. Drying young pistachios down in the fall conditions them physiologically to resist injury from the first freeze, typically around mid-November. A fall application of zinc sulfate, in powder or liquid form, has traditionally been applied during the third and fourth week in October to provide some zinc nutrition and assist in driving the trees into the early stages of dormancy. Young, tender shoot growth present in late October is at risk of freeze injury. Depending upon the severity of the first freeze event, trees still actively growing have been killed back to the main trunk. Growers have reported limited availability of zinc sulfate at much higher cost this fall. Yes, I know the fall zinc spray does not immediately desiccate all the leaves, and its value is in question. I am trying some alternatives, and will let you know if there is a better substitute.
9. Rootstock that was planted later in the spring and budded late has scions only 6-12” tall. Growers are irrigating late in hope that they can get a good percentage of them 52” above the soil line. Depending on soil texture, the latest I would gamble with late irrigation is October 1 in a fine sandy loam soil. Heavier textured soils hold a lot of water and, if they are not saline, could easily carry a newly budded tree into late October with a cutoff date of September 15, which is two weeks later than I recommend. I’m not taking the late irrigation bait; there is too much to lose for the small, long-term gain!
10. PRAY FOR RAIN!! We are BEYOND desperate need of it!
11. Happy Farming!
@PistachioPower PistachioPower