Almonds – Hull Split Spraying Eases Into Gear In Lower SJV – AgFax Tree Crops

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Owen Taylor, Editor


Hull splitting has started on a limited basis in Kern County, and at least a few applications should have cranked up by now. More treatments will likely be made in the southern San Joaquin Valley this week, with momentum picking up on a wider basis after the Fourth of July.

Mites mostly remain in the background. Treatments have gone out in scattered blocks but the bulk of miticides will likely be included in hull split sprays.

Disease varies from concerning to nonexistent.

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Nick Groenenberg, Independent PCA, Hanford:

“We sprayed a couple of fields where we’re finding mites. Where we didn’t treat, we’ll wait until hull split and include a miticide then. The timing for that looks like it will be between July 6 and July 10. Most of our ant bait is out, so we’re in pretty good shape with that.

“Pistachios have been pretty quiet and are looking good. The 1,700 degree-day spray timing is coming up on about July 10. Where fields have puffers, growers are wondering about holding off on that first spray and going with the 2,200 degree-day timing. That’s something we’ll be discussing.

“In cotton, we’re having to treat quite a bit for lygus and are picking up aphids now and are spraying for them, too. Thrips are getting kind of heavy in some upland varieties, and we’re thinking about how to approach that. The cotton is growing pretty good, although the weather keeps cycling between hot and cold, so I’m not sure plants always know how to respond.

“Tomato harvest could start on July 8 in places, if not sooner in a few fields. Alfalfa still looks good. We did spray a few fields for worms, but it’s growing well and cutting good.”

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

“Almonds are very close to hull split and everyone is paying attention. I’m hearing that a few NOW eggs are turning up in low numbers around the Sacramento Valley. So, it appears that egg laying is beginning ahead of hull split.

“This might be a good thing because the first females won’t lay on the viable nuts since they haven’t split yet and aren’t emitting the plant volatiles that draw moths to them. Instead, the females should be going to blanks and mummies, but those provide a less nutritious food source. That will delay development compared to the eggs that hatch on sound nuts in July.

“From a population standpoint, maybe that will slow their development. So, finding eggs isn’t a reason to spray if the nuts you want to protect haven’t split yet.

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“PCAs and growers I’ve talked to are thinking that hull split will start in maybe a July 4 to July 8 window in the Arbuckle area and sprays will start once the sound nuts begin to split inside the orchards about that time.

“With the next flight ‘in the air’ and laying eggs, keep an eye on sound nuts splitting on orchard edges and spray those edges to protect nuts on the perimeter.

“In walnuts, I’ve heard of some late-June husk fly catches. Codling moth counts edged up a little in places. I’ve heard very little about disease in walnuts or almonds stemming from the wet second half of May. That has kind of surprised people – including me.

“Fruit bins are positioned now in the early peach varieties, which always is the first sign of any harvest starting in this area.”

Tony Touma, PCA, Bio Ag Consulting, Bakersfield:

“We will start our first hull split sprays tomorrow (6/29) and that will continue for the next 10 to 14 days, depending on the location.

“We’re finding hull splitting around edges but very little splitting within the orchards quite yet. But with larger growers, it takes 10 to 14 days to spray everything, so we’ve got to start somewhere. By the end of next week, I suspect that almonds will be splitting very aggressively.

“Mites are still on the light side, kind of in the background. So far, no big flareups.

“Our main worry in almonds right now is rust, and it has started moving in some fields. Once it does begin moving, it doesn’t stop and it can roll on into September and cause a good deal of defoliation. You can’t stop it but we will add a fungicide with the hull split spray to slow it down.

“The objective now is to hold onto enough leaves to finish out this crop and set things up for 2020’s crop. Trees move into bud differentiation over the next 4 to 6 weeks, and trees need the leaves to produce enough carbohydrates to get the buds out when the time comes. We don’t want rust to weaken trees to the point that they fall short on that.

“We’ve seen this kind of defoliation happen before. It’s not the end of the world and you can get through it. But it’s something you’d just as soon avoid.

“In pistachios, we’re monitoring for plant bugs. All the mealybug sprays have wrapped up.

“In cotton, we’ve been fighting lygus. When the heat arrived in the first week of June, lygus exploded in our cotton north of Buttonwillow and we were finding 30 counts. As of Tuesday (6/25), they were still at 22 to 24. After 4 sprays, it still looks quite bad. At one point, they took off every square on 320 acres, and fields have probably lost 33% to 50% of the potential crop.

“The bottom crop isn’t there and plants are barely starting to make squares here at the end of June. It’s bad enough that several growers have wondered about disking up the worst fields. On top of all that, aphids are beginning to show up.

“South of Buttonwillow, square retention is less than normal but the situation is at least manageable. That area north of Buttonwillow tends to have heavy lygus pressure but it’s been 7 to 9 years since we had a year similar to this. In that year, we went into July without blooms. Right now, we’re just trying to find squares. We’ve got 7 or 8 main branches without any fruit on them.

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“Lygus aren’t just taking off squares, they have damaged the plant, itself, by destroying the terminal. Plants are making lateral branches and we’re seeing that candelabra-like growth pattern. In fields right around Buttonwillow, cotton looks okay.

“In alfalfa, worms have not developed in big numbers yet and we’ve only sprayed a handful of fields.”

Kris E. Tollerup, IPM Cooperative Extension Advisor, Kearney AREC, Parlier:

“A PCA in Kern County said he’s finding some hull splitting this week. Once hulls start splitting, how early treatments should start can partly depend on how much NOW pressure has developed in an orchard. If pressure is light, maybe you can hold back and get away with a single spray.

“But if populations are heavy, you should probably go on the early side and then come back with that second residual spray 3 weeks later. The tricky part is judging whether pressure is light or heavy or something in between. It’s a subjective thing based on past experience compared to what is in an orchard right now.

“Because this is the first generation to infest the new crop, female moths have plenty of nuts to lay eggs on, so it’s hard to make a determination based on eggs because those traps don’t pick up enough eggs to see a trend. Pheromone traps are more helpful – especially if you have historic data about what flights are doing.”

Regardless of what is believed, almonds are sensitive to water stress during the summer. Moderate to severe stress through June and July has been shown to reduce kernel weights.
Citrus, nut, and grape growers will receive information on early-stage problem detection technology and its place in managing tree-crop yields during four California sessions in July.
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