Here is this week's issue of AgFax Tree Crops California.
OVERVIEW
After a relatively dry January, rain has come on like gangbusters in California during February. After some showers late last week, heavy rainfall hit most growing areas starting Monday and was expected to continue off and on throughout much of this week. More precipitation is expected into next week. Impact on the almond crop may vary by location and how far along the trees are in the bloom cycle.
Growers have been scrambling to apply full bloom sprays or pink bud spray. It seems the biggest concern during bloom is brown rot disease. After full bloom, red leaf blotch and anthracnose could also pose a threat. The good news is that the recent storms have generally been accompanied by relatively cool weather that may ward off pests or disease. There was some worry that warmer weather might accompany next week’s storms, at least in the south.
Things are pretty quiet for pistachios and walnuts. Ther’s talk about scheduling mealybug spraying in a month or so for pistachios. For the most part, walnuts remain dormant.
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CROP REPORTS
Justin Nay, PCA, CCA, president, Integral Ag Inc., Chico:
Rain: We’ve had a lot of rain. There are a lot of trees under water. Wind hasn’t been much of a factor, but it has interfered with potential aerial applications or sprays. Most everybody got something on before the weekend, in between rain events and in front of this week’s rain, but we were moving into full bloom in a lot of the almond blocks. With a full week of rain and more rain forecast next week, we’re trying to find windows for when we can accomplish our next treatment before the one last week wears off. There was expected to be a lot of clamoring for aircraft for a few small windows of clear weather during the later part of this week.
Almonds in bloom with some water accumulating in Colusa County. Photo courtesy of Justin Nay.
Brown rot: The main disease while we’re blooming is brown rot. Last week some growers started pink bud sprays on some varieties. Then we bloomed very rapidly and moved into full bloom. Some growers at the end of last week were putting on full bloom sprays or pink bud sprays, mostly targeting brown rot. Now, as we exit full bloom and start into petal fall, we’re getting leaf out, so now we have to worry about red leaf blotch, anthracnose and brown rot all at the same time. If we can’t spray until the end of next week, we’re going to have the potential for picking up a number of different diseases and a number of pathogens.
Frost: In the north state, there could be five or six days of rain next week as well as frost. Some areas could drop to 26 degrees, and they could see some significant damage. Most of the flowers are no longer yellow-centered flowers, so it does look like the bees have already done a lot of work. Perhaps the bad weather this week won’t be as impactful, at least for a lot of Northern California ranches, as it would be as if we had full bloom into the rain.
Pistachios in standing water in Colusa County. Photo courtesy of Justin Nay
Walnuts/pistachios: Most of the pruning is wrapped up on walnut trees. There is still some hedging going on, a little bit of pruning and some preemergents if growers had swept their berms. For the most part, walnuts are dormant. On pistachios, we’re doing a few late preemergents, there’s a little bit of pruning going on, and we’re starting to have conversations about gill’s mealybug sprays in a month or so.
Rain: We’re definitely grateful for the rain — but it couldn’t have picked a more challenging window. Most areas were expected to receive between 1 or possibly 2 inches this week. The timing is what makes it difficult. Almond orchards moved from almost zero bloom to full bloom in just five or six days. That rapid progression didn’t leave much opportunity to get first bloom sprays out ahead of the storms. The latest system started last weekend, and we weren’t expecting much relief until this past Wednesday. So now we’re in the middle of full bloom trying to squeeze in applications between rain events starting this week. It’s been tight, and every window matters.
Nonpareil and Monterey almond trees at night in Tulare. Photo courtesy of Nathan Stewart
Strategy: At this point, the next steps depend heavily on crop stage once the weather clears. If we’re moving into petal fall with new leaves pushing, that’s one management strategy. If we’re still sitting in full bloom, it’s a different approach altogether. We’re evaluating orchards carefully and preparing to adjust quickly. As soon as conditions allow, we’ll also be lining up the first fertilizer applications in almonds. In the meantime, growers are doing what they can -- chipping brush, mowing weeds and trying to stay ahead where field access permits.
Disease: With extended wet conditions, disease management is top of mind. Brown rot, shot hole and red leaf blotch are the primary concerns right now. The immediate goal is making sure every block receives at least one fungicide spray. Seeing when the storm lets up will dictate what we do on the second fungicide. The challenge will be determining whether we can get in with ground rigs or if conditions will force us to go by air.
Dormant spray: The rain itself hasn’t caused damage to almond trees so far. However, days of prolonged leaf wetness does raise concerns about brown rot. The silver lining is that temperatures during this storm have been below 50 degrees, which may help limit disease development. In a few areas where we’ve seen minor mite pressure the last couple of seasons, growers are beginning to reconsider winter dormant spray programs as part of their long-term management.
Walnuts/pistachios: Compared to almonds, walnuts and pistachios are relatively calm at the moment. In pistachios, we’re scheduling mealybug applications in blocks that experienced pressure last season. Walnuts, however, are not requiring much attention right now -- they’re in a holding pattern as we monitor conditions.
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Dan Prentice, PCA, Prentice Ag Consulting, Bakersfield:
Rain: We had a couple of showers early in the week. There was a significant amount of rain but a lot of drying in between. As far as the rain event, it was not the worst-case scenario for the almond bloom. We had some pretty good wind alternating with rain. This week’s rain started around mid-morning on Monday. More rain was forecast for Tuesday night and Wednesday. It looks like another storm is going to be moving in Tuesday and Wednesday of next week. We’re in a bit of a wet pattern.
Almond blooms on a Monterey almond tree near Shafter. Photo courtesy of Dan Prentice
Bloom/disease: Everything has some level of bloom going on. I have a few orchards that are nearing full bloom, some that are at 20%, 30% or 40% bloom. The timing of the rain is not ideal. The first system was relatively cool, which was helpful. It looks like the system that is coming in next week is going to be warmer with temperatures in the 60s. That will be a little more concerning for disease development. Brown rot is the primary disease we’re concerned with at bloom time. It develops a lot more readily with warmer temperatures. I have not seen any diseases or pests yet, but it won’t be long. Things are moving along very quickly. The bloom happened really fast. We’re starting to see leaves pushing out in most areas already. That’s a little on the early side.
Impact: Almonds can withstand rain OK as long as we’re getting our fungicides on and keeping the disease down. If it’s raining and the bees aren’t active, that could have an impact. But the bees can make up for it pretty quick when the weather is right. I wouldn’t anticipate that the weather we’re having right now will have too much of an impact on the crop.
A Nonpareil/Monterey orchard nearing full bloom near Shafter. Photo courtesy of Dan Prentice
Pistachios: The pistachios are doing pretty good. There’s nothing going on there yet. We’re about five or six weeks away from bud break starting in pistachios. Guys are still doing some herbicide work, cleaning up brush and things like that.
