“We continue to monitor for mites. Beneficials have been controlling mites in most orchards. Those are mainly sixspotted thrips and a few predatory mites. One block did require a treatment, but predators have otherwise been taking care of mites, which is reassuring.
“Younger almond orchards are a different situation. In first-leaf orchards, we always end up with spider mite pressure, and it’s rare that we don’t have to spray a first-year orchard for mites. We encourage growers to keep orchard centers undisturbed after April, with no disking, floating or other activity that stirs up dust. We are planning miticide applications in first- and second-leaf orchards where we have concerns. In third-leaf orchards, we’ll make applications where problems persist, but that’s not as common.
“Planning is underway for hull split sprays in our Nonpareils, and that is trending a few days ahead of July 1. Strategy, materials and navel orangeworm phenology are all factors to consider. Based on the predictive models, this next generation of navel orangeworm will likely coincide with hull split.
“Growers who opted to not front-load fertilizer in March, April and May are still applying small amounts. They increased fertilizer during nut fill and will back off to smaller quantities in June through August. The almond trees are more likely to take up needed nutrients as they utilize water during the warmer months. Growes are going with about 15% of the year’s total in July and in August ahead of harvest but won’t apply anything after harvest.
“In walnuts, codling moth counts are low. Husk fly traps are going in place. Parasites are keeping aphid pressure to a minimum. We find it easier to prevent botryosphaeria with a fungicide spray than to wait for it to gain a foothold. Growers with drip irrigation and micro-sprinklers are applying small amounts of fertilizer through their systems every week or every other week as needed.
“A few pistachio orchards required mealybug treatments. Those growers are adding a material for botryosphaeria.
“Certain fertilizers are also applied through the irrigation systems. We emphasize nutrient plant health during pistachio nut fill, which runs from the end of June through early August.
“Cotton is at 8 or 9 nodes. Lygus counts remain low, with minor square loss.
“Tomato growers aren’t dealing with pests yet. The plants are mostly well established, despite the wide range of planting dates from the beginning of April through May 20. We sprayed fresh tomatoes for thrips as those populations developed, but worms haven’t warranted action.”
Franz Niederholzer, UC Farm Advisor, Colusa, Sutter and Yuba Counties
“Over the last couple of weeks, we’ve been in a pattern with hot temperatures during the week and lower temperatures over the weekend. Last weekend (5/30-31), thunderstorms developed, with a half-inch of rain in places, then the temperatures bounced back to 100 this week. But this weekend (6/6-7), we’ll drop into the mid-70s with a 20% chance of rain.
“I haven’t heard of or seen any uptick in disease following the scattered rain this past month, but it can take several weeks for symptoms to show. Despite cooler periods over the past couple of weeks, evapotranspiration numbers are running at 100% to 110% of average.
“Growers should start considering when to taper down on irrigation if they plan to take a strategic water-deficient irrigation (SDI) approach as we move into early hull split. The target for hull rot prevention with SDI is -14 to -18 bars on the pressure chamber once Stage 2B hull split arrives.
“With heavier soil and sprinklers, you’ll need to reduce total irrigation soon to reach those target numbers by the end of this month. In orchards on drip irrigation or lighter soils, you probably don’t need to start as early, given a smaller soil water bank. Don’t try this without access to regular pressure bomb scheduling.
“The overall strategy is to slowly back off on the length of irrigation sets, not to eliminate sets. That induces the moderate stress needed to gradually manage hull rot. Then hold that level for two weeks in early hull split. Don’t go back to full irrigation until harvest dry-down ahead of shaking.
“Hull split is within a month now. Kernels were filled as of last week in many orchards in the lower Sacramento Valley. Prepare for early hull split applications, which likely will begin in the last week of June. Don’t base your planning on early July for the start of spraying. We’ll know how the timing will run when we get closer. But it’s better to be prepared and wait a bit longer if necessary than to suddenly scramble to spray earlier than you expected.
“Navel orangeworm and peach twig borer degree-day totals are 810 and 1,116, respectively, at Nickels Soil Lab as of Thursday, June 4. These numbers use an early, mid-March, biofix.
“It will be interesting to see if the second-generation pattern matches those biofix dates. Right now, the PTB moth patterns are not following what you would expect from a mid-March biofix, but I think widespread May sprays in this area may have reduced PTB moth populations, making moth catches harder to interpret over time.
“Walnut husk fly catches started earlier than normal this year. Typically, the timing is mid- to late June, but this year they began appearing in traps in early May. This year, those traps already should be up because of this early trend.”
Todd Fukuda, Weinberger and Associates, Hanford
“Almonds remain steady and show minimal plant bug damage. We continue to monitor but probably won’t need to spray anything until hull split. Timing for hull split appears to be on target compared to previous years. The last week of June would be the earliest we would spray, but most likely we’re looking at the first part of July.
“Mite populations remain low. We didn’t see any flare-ups from the first heat wave and hope this last round of heat didn’t flare populations, either. Late-season tissue diseases – rust and alternaria – also remain low.
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