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
Test shaking may have started on a limited and scattered basis in the lower San Joaquin Valley late in the week. More testing seems likely this week.
The second round of hull split sprays has wrapped up in parts of our coverage area and a third application seems likely in places later in the month or into early August.
Progress towards maturity seems to have drug out longer than expected. As the theory goes, trees are dealing with excessive heat and have held back on most other processes.
Franz Niederholzer, UC Farm Advisor, Sutter/Yuba Counties:
“Things are just kind of staggering along in this heat. It’s been in the upper 90s and up to and above 100, plus temperatures at night have been above average. I’ve been talking for some time about our rollercoaster temperatures this year, but summer seems to be here now (7/20).
“This week, we’re not seeing much in the NOW traps but we could expect the next spike at the tail end of July and in the first week of August. That’s usually when we detect that big number as the third generation becomes active.
“I think we’re 4 weeks to shaking, although I’m sure several of the bigger operations will start sooner because they have to cover plenty of acres, plus they have their own equipment. Overall, people are keeping water going. Not a lot of spider mites have developed yet, although this is the kind of hot weather that brings them out.
“In walnuts, no husk fly have been caught at the Nickels Soil Lab, although I’m hearing that low counts are showing up in traditional hot spots in the area. However, we didn’t see our first husk fly at Nickels last year until the last day of July. Harvest has started in the early cling peaches in the Yuba City area.”
David A. Doll, Pomology Farm Advisor, Merced County:
“Nonpareils are splitting just about everywhere in the county, regardless of soil types or root stock. It’s been hot, with highs mostly over 100 for the last couple of weeks. That will really ramp up the NOW pressure.
“People are asking about harvest timing. Test shakes can be started as soon as you’ve hit 100% of the nuts in stage 3 of hull split in the IPM guide. That means there’s a half-inch opening on the nut. Some people say that’s a little early but I would rather growers shake trees at least a little on the early side.
“By going early, you have a little more moisture with the hull, so it would shake a little easier. Also, once the nuts are on the ground, you do have a reduction in NOW pressure. Beyond that, it would reduce the impact of hull rot because the hull is no longer attached.
“On the other hand, if you shake early, you have to dry longer, and that can make irrigation a bit tricky. If you shake too early, you won’t get the nuts off, so you want to make sure that you’re seeing nearly all the nuts at that time when you look down in the split.
“Very few people test shake anymore. They just send the shakers through and expect them to do the trick. Ideally, if you test shake a tree, you want to see 98% to 99% of the nuts fall, at least in Nonpareils. If they are too green, they won’t shake off, so you know to hold back.
“Generally, though, people tend to shake on the late side rather the early side. But, the longer the nut is on the tree, the more exposure it has to NOW. Research and observation bears that out, so early harvest is a great cultural practice in reducing exposure to NOW.”
Dan Prentice, Prentice Ag Consulting, Bakersfield:
“We’re right in the middle of hull split. Where we’re doing a second hull-split spray for NOW, most of those went out this week. Except in a few scattered hot spots, spider mites aren’t an issue (as of 7/20).
“The second spray in a lot of cases have included a miticide. That’s different timing than in most years. Where we have mite pressure, the miticide typically has gone in with the first hull split spray. With some blocks this year, we went by air the first time and by ground the second time, while in other locations we went by ground both times.
“Test shaking is about to start on a very limited basis. One grower said he would try some today, although I don’t know how that went. A little more test shaking will crank up next week. It will still be August 1 before we see much happening, though.
“In pistachios, we haven’t done any NOW spraying yet. A little citrus flat mite has started showing up, although we’re not doing anything about it yet. We’re also waiting to see how many pea splits we get. The kernels are filling pretty good now and I saw one pea split the other day but haven’t seen much past that.
“If we do start seeing a lot showing up, I may go after the flat mites, maybe with a NOW spray.
“In tomatoes, we’re getting close to harvest. A few tomato trucks are running around, so I know harvest is underway somewhere. My tomatoes look pretty good right now. We haven’t had any worm issues the whole year. Black mold is really hard to find. We are treating a little for that now, but more on a preventive basis.”
Chris Morgner, PCA, Agri-Valley Consulting, Merced:
“Hull split is progressing in most almond orchards but somewhat slower than normal. In certain areas, you’ll have blocks that are a little earlier because they didn’t get quite enough water, but that’s just a handful of locations. Most Nonpareils are maybe at 10% hull split right now (7/20), although that can change pretty quickly at this point.
“On a fairly consistent basis, I’ve been finding brick-red NOW eggs on hulls and started seeing this with the early splits. This is a bit out of the ordinary, and I’m finding them in both the blocks I work and in random blocks where I’ve stopped and checked.
“NOW had good survivability through the winter with mummies and then substantial egg laying on mummies again in April and May, so plenty of eggs are being deposited now. We’ll have a challenge ahead of us.
“Knowing that, we sprayed at early hull split, with the bulk of sprays going out between July 5 and July 10. Hull split was a little later this year than in 2017 and harvest will start a little later, too, I suspect. Where we sprayed around July 5, the second spray would be 15 to 20 days later, and some guys are spraying right now. The first of those applications actually went out a couple of nights ago.
“We are going in with a second treatment on a pretty big portion of the crop that’s past the third leaf. Enough NOW activity seems to be developing that we might do a third spray before Nonpareil harvest on a portion of blocks. This will mainly add protection for pollinizers.
“I don’t know if that third spray will be on 50% of our blocks, but some growers were really hurt last year by NOW and they’re on the warpath this year. Our Independence trees fall into that, too.
“The pollinizers were the varieties that sustained really bad damage last year. We weren’t seeing problems with Montereys, for example, when we sampled Nonpareils in the field. But when we cracked out Monterey nuts later, we found hatchlings.
“A lot of that NOW activity in pollinizers occurred in the middle to latter part of August, maybe even into September. So, we don’t feel like we can wait and spray after Nonpareil harvest. I’m thinking that it’s already too late if we hold off on a third spray until the first week of September.
“Also, nothing last year in the first part of July indicated that big NOW populations were building. This year, though, we know that they are out there. Even today, we found PTB larvae in some nuts in third-leaf blocks that were 5% to 15% split.
“Miticides were included in the first hull-split sprays and those blocks are still clean. Mite flareups have started in some first-leaf blocks that were sprayed on June 10.
“Our cotton has been amazingly clean. Any treatments for lygus have been on a case-by-case basis. Maybe one application went out in early June. Retention is very strong. In tomatoes, we had to treat pretty much all of our processing fields for armyworms at some point over the last 3 weeks. A very few acres were sprayed a second time. Maybe a third of our alfalfa was sprayed for worms within the last 3 weeks.”
Jhalendra Rijal, Area IPM Advisor, Northern San Joaquin Valley:
“People are about to get busy with the second hull split spray. Those treatments will get underway next week.
“In some locations in San Joaquin County, some growers did not initiate their first spray until this week because the nuts were not splitting. For whatever reasons, you see those kinds of delays in certain places.
“Spider mites are still out there. But producers should be okay if they included a miticide in their first hull split spray or will include a material in this second treatment. Even where they didn’t have a miticide in the first application, we’re not seeing outrageous numbers. However, the forecast calls for 100-plus high temperatures this weekend, so mite activity could build.
“In walnuts, codling moth numbers are low, based on what I’m seeing in my own traps and in conversations with other people. There are exceptions. One PCA said yesterday (7/19) that he had some high trap counts for codling moths last week and then this week, too.
“That reinforces the idea that codling moths can vary on an orchard-to-orchard basis. On average, though, codling moths are pretty calm right now. Spray timing for the 2B flight is right now or was even a few days earlier, based on my trap counts. Keep in mind that trap counts can vary widely by location.
“We are detecting somewhat more husk fly activity in the 3 orchards where I’m monitoring. We caught a relatively high number of husk fly on those trees last week and this week. But, the husk fly is very location-specific. Where an orchard sustained husk fly damage in the past, it’s likely they could be a problem the next year.
“In orchards closer to the river or in areas with black walnuts, you likely will see more husk fly activity. Also, it’s worth noting that husk fly development is not related to temperature. That’s a huge difference compared to the way other insects respond to degree-day accumulation.”
Rick Foell, Field Manager, Capay Farms, Hamilton City:
“Hull split across our Nonpareils is probably at 85%. For the most part, the pollinizers are still pretty tight. We have finished our second hull split spray.
“We have had triple-digit highs through much of the week. Yesterday and today (7/21) were the first days this week when it remained below 100 degrees, and highs on Sunday will be below 100, too. But after that, highs will jump to 104 to 107 all week.
“I suspect that these trees are under so much stress from the heat that all they can do is transpire. They’re holding their own and neither the trees nor the crop are progressing much beyond that.
“Right now, we plan to make a third spray in 14 days on about 20% of our almond acres and will go by air.
“We included a miticide in the second spray. Except in a couple of orchards that showed some heat stress, trees were pretty clean as far as mites go. But with the forecast saying we’d have triple-digit heat for an extended period, we needed some assurance that mites wouldn’t suddenly blow up.
“In this immediate area, we’ll probably start shaking on August 15. That’s our forecast right now. But on the ranch at Arbuckle, the crop is running close to a week ahead. It’s cooler there, so trees aren’t under the stress that’s slowing them down here, and we may be able to start shaking there sooner.
“We were talking about how weird this year is in terms of spray timing. In past years, everyone made pest-control applications within a few days of one another. But this year everything is kind of a hodgepodge. There may have been nearly a 3-week window in which people started their first hull split sprays. Some of that variation may get back to last year’s NOW damage. Everyone is shooting for the best quality possible and are maybe being more proactive.
“Overall, we had minimal damage last year, just a few loads here and there and nothing like problems with whole fields. But I can understand why people aren’t taking chances. The reality is that you can pay for a spray if you can improve your damage numbers by just a couple of percentage points.
“In walnuts, we’ve been trying to keep them wet so we don’t run into sunburn, but some sunburn is starting to show up now, anyway. When highs are above 105 day after day, there’s no way to fully avoid it. With codling moths, we have one more treatment ahead of us but it will be based on the flight. We haven’t seen much in the way of mites and have only been spot spraying where it’s needed.”
Nathan Stewart, PCA, AgVantage Consulting, Inc., Visalia:
“We finished our first hull split spray. With this heat, we hoped that hull split would have proceeded faster. Instead, it’s dragging out, which is requiring a second spray. We’re lining up a bunch of those for next week.
“When the pollinators start opening, we might have to come back a third time. For whatever reason, hull split is really misaligned this year. That’s making it difficult to keep things wet and work spraying around irrigation, plus try to line up harvest timing. As things look now (7/21), it will probably be the first week of August when my earliest blocks are ready.
“Mites seem to be holding okay. We are having to watch borders. They’re popping up just here and there, but I haven’t seen any big mite outbreaks or blowouts. NOW are very inconsistent in almonds. We’re seeing eggs and both first and third instars, which indicates we’ve got a lot of overlapping flights. Trap counts are insignificant now because moths are going to the nuts.
“With pistachios, we’ll hit 2,200 hours next week in most of my area. I’m still watching NOW egg counts and we’re finding a lot of pea splits, so we’re lining up sprays next week. That will be more of a population-control measure. I’m estimating that the hull-split spray will be a couple of weeks after that.
“In walnuts, codling moth counts are increasing. They’ve been very light up until now. I’m thinking that we need to spray at the beginning of the third generation. If we’re lucky, that will line up with husk fly applications.
“I did make some husk fly treatments about 2 weeks ago in areas where we’ve had them in the past. Additional treatments didn’t start until last week where I thought it was necessary. With mites in walnuts, nothing is out of control, just a few hot spots and along borders.”
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