Here is this week's issue of AgFax Tree Crops.
Our thanks to BASF’s California team for once again sponsoring our coverage of tree crops in the Central Valley.
Owen Taylor, Editor
It’s too early to tell how much of a hit last week’s frigid weather inflicted on the 2018 almond crop. So far, perceived injury ranges from none to substantial, at least in some orchards. One major unknown: How long will it take for the full extent of injury to become completely apparent?
While sub-freezing temperatures were the main player, a number of factors may skew the results from one block to the next. That might include the presence or absence of wind, whether thicker canopies may have helped insulate blooms and to what extent blooms had opened. Also, how long did the coldest temperatures linger?
In any case like this, questions arise about how much set the trees actually need to make acceptable yields and whether they might compensate with nuts that made it through.
Fungicide applications have mostly remained on hold due to a general lack of rain, based on most of the reports this week. Rain is in the forecast now, but a higher percentage of applications will likely go out by air. With growers running water to minimize frost/freeze damage, orchard floors are too wet to run ground sprayers.
Prune growers meeting, March 2, Yuba City. Connect to more details in our Links section.
Spring Almond and Walnut Nutrient and Water Management Field Day, March 13, Nickels Soils Lab, Arbuckle. Connect to more details in our Links section.
Spring Almond and Walnut Nutrient and Water Management Field Day, March 27, Corning. Connect to more details in our Links section.
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Franz Niederholzer, UC Farm Advisor, Sutter/Yuba Counties
“I am hearing reports of damage due to the cold weather. To what extent will it end up being economic damage? That’s an unknown. How much set do you really need to make an acceptable yield? Some of what was lost may not be necessary to produce a normal crop.
“That’s not to say we won’t see at least some yield loss. It has been cold enough to expect a degree of damage. If you’re making up an equation for a bad situation, this qualifies – extremely cold temperatures and sensitive flowers.
“How cold it’s been depends on the location. The farther north, the worse it’s probably been. I’ve been told about lows down to 25 for an extended period, which isn’t good. We had frost at my house last night (2/22) before midnight, so it did remain cold for an extended stretch. How much wind a given area received might have helped minimize some effect.
“I don’t think we’ll know the full extent of this right away. A good deal of water did go out for frost prevention.
“A lot of early cling peaches were at risk, and farmers ran water in those orchards, too. The walnut guys are running water, although I suspect they’re reloading the profile. Some prune growers might be doing the same thing. A lot of water was used, mostly well water, and helicopters were maybe flying over bigger plantings on the west side.
“At the very least, there’s been some level of freeze risk in the Sacramento Valley every night since last Sunday (2/18).
“So far, I doubt if many fungicide applications have gone out. It’s been cold and dry until last night (2/22) when brief showers developed in places. There’s talk of warmer weather and rain next week. With that, people will probably begin lining up fungicides. With all the water applied for frost protection, the ground is pretty saturated, so spraying by ground could be a problem.
“All that water will be an issue, too, where root stocks are vulnerable to phytophthora. It will be interesting to see what bacterial blast looks like because it loves frost. Again, it will take time to see how all of these points play out.”
Sara Savary, PCA, Crop Care Associates, Fresno
“How much damage I’ve found depends on the location. In places, yield potential is completely gone. In other orchards, blooms didn’t get touched.
“I’m not sure that all those difference can be explained by temperature, alone. On one ranch the crop was wiped out on third- and fourth-year trees but the fifth-and six-year trees look just fine. The younger trees are more open, which might explain why they were hit so hard. The older trees have more branches, which maybe held the heat better.
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“On what appears to have been the very coldest day, low temperatures ranged from 28 down to 20. In the past, we’ve had areas with cold conditions and frost damage. Those were kind of isolated cases, but this seems to be Central Valley-wide. I can’t recall anything like this where all of my growers were hit at the same time. To some degree, everyone sustained damage. If anything was blooming, you can see some effect now.
“Most of my growers got a fungicide out. We mostly waited until close to bloom. The forecast kept calling for chances of showers, so we figured we might as well make applications. But there’s been no rain lately. The roads outside of my house were wet last night before I went to bed, but I didn’t actually see any rain.
“None of our tomatoes are in the ground yet. I expect to find some damage in citrus. In the stone fruits, the very earliest varieties were hit – about as badly as the almonds, if not worse.”
Dale Deshane, PCA, Supervised Control, Bakersfield
“As far as I know, the coldest temperatures where we work almonds were down to 23 to 24. That was in Delano, and they said it remained that low for about 4 hours.
“Honestly, I can’t ever remember it being that cold during full bloom. We can get frost later in March, but it’s unusual to see anything like this in February. A lot of growers recorded lows at 25 to 26, with mid 20s over a wide area.
“As far as duration goes, reports vary. In places, people say it lingered in the 20s for 6 or 7 hours, while other guys say it only lasted 2 to 3 hours where they are. I do know that on Tuesday and Wednesday it was extremely cold and it stayed cold until 10:30 a.m. If the coldest conditions set in at midnight, then it was cold for quite a while.
“We are not finding any damage in any of the flowers we’ve sampled and have been checking all week. I keep hearing stories about bad situations farther north, with all the flowers on the ground. But I also understand that it was much colder in those areas, even into the mid to upper teens in the coldest points.
“That’s not to say we won’t see effects here later, say 7 to 10 days from now (2/23), but we’ve pulled apart plenty of flowers and have yet to see any real injury.
“Little showers came through Bakersfield last night and left the windshield a little wet, but today it’s been cold all morning and overcast. I’m in Buttonwillow right now (late afternoon, 2/23) and it’s 51. Compared to the rest of the week, we did not have those freezing morning temperatures. Rain is in the forecast next week.
“As far as fungicides go, we’re sitting on most everything. A few growers opted to spray, but we still haven’t done many applications. If we get into a wet period next week, a lot of applications probably will go out by air. Plenty of orchards are still wet where growers ran watering for frost protection, so it will be too wet to spray by ground.
“Development is really strung out now. We had all that early talk about a flash bloom, but the bloom now is erratic. One tree might be at 10% bloom but 2 or 3 trees over they’re at 100%, and you really can’t connect these differences to varieties. A lot of orchards are like that.
“Hard shells are just starting to bloom a little. The bud set looks really good in places – potential for nice yields in that part of the crop if they hang on. But we also see a lot of trees around that don’t seem to have a good set. Even where trees started blooming early, that bloom slowed down. Leaves just started coming out over the last few days, enough that you can drive by and see a little green cast when you drive by.
“We’ve been checking for brown rot, which normally isn’t a problem for us, but I’m more concerned about jacket rot if it does get wet next week. Again, we’ll start flying on fungicides if it turns wet, but who’s to say how that will go? Weather forecasts have been unreliable. They’ll call for rain but we get nothing. Normally, we should have received over 4 inches of rain by now, but the total is probably more like an inch.
“In alfalfa, we’ve been spraying for weevils. Blue aphids are pretty bad in some fields. In a few cases, we’re finding more pressure from blue aphids than weevils. We’ll probably make some treatments next week between rains, and we started spraying weevils more than a week ago.
“Tomatoes took a hit from the freeze. Growers will try to keep a few fields. In places, losses aren’t consistent across fields. You’ll see 10-foot strips where we lost plants but everything else looks okay. Planting didn’t start until last week, so in those cases growers will plug in replacement plants next week.
“Potatoes were wiped out, at least above the ground. They can bounce back but you end up with another crop of tubers, which means a bunch of small potatoes and nothing will size up correctly. People backed off on planting peppers or watermelons to see what the weather did, but that should get underway next week.”
Gary Gliddon, PCA, Treevine Consulting, Modesto
“Tuesday morning was supposed to have been the coldest, with more low temperatures again on Wednesday – but not quite as low.
“Where I could get into any of our fields, I’ve been checking them for damage. So far, the only instance where I found injury was in the Sonora variety, which is ahead of everything else. Where the nutlet had started growing past the little ovary in the flower, about 60% of those were burned up. That was on Tuesday morning, although we’ve certainly had more cold conditions since then.
“One PCA says he thinks more flowers were hurt than we might think because it’s harder to distinctly see the damage unless you cut into them. He thinks that when you’re pulling flowers open and looking for brown spots, it’s possible to miss them. His idea is to use a razor blade or really sharp knife to cut them. If that’s the case, we may be missing some damage.
“Someone also speculated that it might take a day or two for injury to show up. I’m not sure about that, but we’ll know more soon enough. Some pretty bad reports about damage have surfaced to our north.
“Very few fungicide applications have gone out because there hasn’t been a reason to spray. A little storm is coming through next week, so a couple of guys asked for recommendations. I cautioned them to make sure they had a crop to protect before they spent any money on it.
“In places, there won’t be a crop, I think. With most of my growers, though, the temperatures haven’t been as low as what we’re hearing elsewhere, and I think the majority will be okay. Again, we’ll see. It’s supposed to drop to 25 to 26 tonight (2/23), which can cause damage.
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“We’ve seen variability between what the forecast’s lows are and what actually happens in the field. That’s been kind of scary. One guy said the forecast called for 30s the night before but, in fact, it fell to 27 at his place, even to 26 in spots. As he pointed out, forecasts can’t predict what will happen in each field.
“With the way things have been going, it appears that we generally will have a reduced crop over the state. How much is anybody’s guess right now.”
Todd Fukuda, Weinberger and Associates, Hanford
“I’ve been checking closely for the last 2 days (from 2/24) and the trees I saw have not been hit hard by the temperatures. From the time the first freeze warning went out, our guys started running water like crazy.
“Everyone has been in the same boat. We’ve had a series of mornings with lows in the mid 20s but the forecast also called for at least some rain as the cold conditions played out. We were trying to put frost protection in place, get fungicides out but still be ‘bee safe’ where we made applications.
“As things turned out, the rain really didn’t develop, just a light sprinkle. Rain, though, is in next week’s forecast, with 20% to 40% chances, depending on the day. However, we have fungicides in place now, which should carry us through whatever rain develops then. Most of our growers were able to line up aerial applicators because fields were too wet to spray by ground.”
California Almonds, Walnuts: Water And Nutrient Field Day, Corning, March 27 2-25
California Prunes: S. Sac Valley Meeting Coming Up March 2 2-25
California Almonds, Walnuts: Nickels Spring Field Day – Focus On Nutrients, Water Management 2-24
Almond Board of California: 2018 Board of Directors Election Results 2-22
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