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Entomology Update with Monique Rivera
Well, folks, it looks like we’re off to a weird start to the season with a week of summer weather and now in western New York, cooler and wetter conditions. Maybe a weird start is more like a stumbling start because it will warm up again for a day or two in western New York, and then go right back to cool and wet. But either way, we are collectively heading towards Pink, and there are, as always, some insects to consider and think about treatments for.
If San Jose scale is a concern, it’s not too late to include a treatment for this. There are still options until foliar development progresses to the point where coverage will decline. So the real aim of this treatment is to make contact with the woody parts of the tree and hopefully make contact with any eggs or immatures that are there. So if you’re focused on getting an oil applied for this, there’s still time for a 1% oil spray through tight cluster again to cover those woody surfaces. If you think you will need more control, there are other insecticidal options to add. In particular, I would consider Centaur or Esteem, both of which are insect growth regulators.
So last week I spoke about the idea of bulletproofing IPM programs, and I think a good thought experiment about that would be to think about what your management program would look like if Organophosphates and Pyrethroids, for example, were eliminated. The idea of this is kind of ridiculous because organic management can use Pyrethrins, which are the direct plant extract, but in all honesty, at higher levels this is being considered. And it’s something that along our journey here on Scaffolds, I probably will continue to mention, because if we don’t think about it now, I really think that it will sneak up on the industry as things start to be considered for elimination. And so it would be good to start to think about again what your program would look like if you could not use whole classes or mode of actions of insecticides. It would be really helpful to your future programs to start considering that. Not that I know that this is coming down the pike in New York State, but I do know that in California, before I left, I was asked to review the use of pyrethroids, which is the beginning of that consideration.
Pathology Update with Kerik Cox and Liga Astra Kalnina
Let’s talk a little bit about fireblight, since that’s going to be on everybody’s mind for the next coming couple of weeks. I want to start off talking a little bit about the 2022 season. In 2022, there was some devastating firefight, but it was pretty much stuck in the Finger Lakes region with some weather coming at the end of petal fall, just after petal fall right at the end of May.
Last year, the season was pretty cool, low risk bloom that seemed to linger in the area for this region. And then we got these really hot, stormy, high fire blight risk weather right at the end of bloom and petal fall right, particularly in the Finger Lakes area. I mean, these are the perfect conditions for fire blight. Got a lot of systemic shoot blight infections right in the Finger Lakes only. But interestingly, this pattern was pretty much like the previous year – cold bloom, hot petal fall and post petal fall weather.
The good news is, for most farms east and west of the Finger Lakes, this period of hot weather was either too late or just not severe enough to lead to infections. There were some outbreaks in Wayne county, but the situation was not as dire or widespread in the areas beyond. Many growers that were using strong bacterial programs to the end of bloom were able to manage it, while others may have experienced some short outbreaks of shoot blight during storms or shortly after petal fall.
Plantings on Long Island and Hudson Valley were well beyond bloom and able to escape these infections.
With the early hot spring that we’re experiencing right now before bloom, we should remain vigilant and prepare for these higher risk periods of erratic hot weather that often come with storms. These periods, just like the one last week, ended with a big storm, and now we’ve got cold weather. So growers need to be prepared from start to finish and during the susceptible period, from bloom all the way to petal fall, and finish strong with their most effective options.
So what are we looking at right now? The Hudson Valley is in bloom or on the cusp of bloom. Temperatures this past weekend were in the 80s. Risks were extreme or even higher, particularly for the early flowering cultivars and pears. We’re now in a cold spell for a couple of days, but by the end of the week, we’re going to be back in another spurt of high 70s, low 80s throughout the state. In western New York king bloom could occur this weekend, which will be important to watch the weather, particularly in cider blocks and pears.
Follow the extension specialist alerts and fire blight predictions. If you’re concerned about carryover inoculum from fire blight last year, go ahead and think about applying prohexadione calcium with or without that little bit of Acibenzolar-S-methyl at pink, and this will slow down vigorous growth in trees if they start to move really fast. And also that slowdown of growth will slow any migration of bacteria that creep in through the system should infections occur later.
So we did just pass a really big ascospore release this past weekend. In a lot of regions, especially when we’re thinking about the Hudson Valley, there’s another infection event predicted this weekend as the weather is warming back up again, and there’s another 19% ascospore release being predicted. It would be a good thing to make sure you apply a fungicide maybe Saturday. There are some good options. You could do Tesaris or Miravis or maybe Inspire Super or Cevya if you also have rust, but you can choose any option that you might have, any SDHR or DMI that you have on hand.
If your apples are already at pink, this predicted warm weekend might push them into bloom. If your trees are in bloom, consider applying Streptomycin Friday as there is an infection predicted on April 22. Blossom Protect could also be a really good option, but as Kerik said, please take tree vigor, fire blight history, and cultivar susceptibility into account when you’re making these applications. And we might check back in later in the week if these conditions change.
When we’re looking at Capital District, there’s also a moderate infection predicted for apple scab as well as there’s 24 hours of leaf wetness predicted this weekend. There’s only 12% of ascospores being released. So, depending on when your last fungicide application was, maybe Friday or Saturday would be a good day to apply a biological. Or if you’re very worried, maybe you should apply a single site fungicide as well. With the weather getting warmer, the same thing goes for Capital District as well. There might be a fire blight infection predicted on the 22nd as well. Maybe you should apply Blossom Predict on the 21st, but check back on NEWA to see what your specific station is telling you.
When it comes to Wayne County and Niagara, there’s currently no infection predicted. Maybe there’s like between two and 3% of spores being released or not at all. So just maintain your desired fungicide coverage and there’s no need to worry about fire blight as no first blossoms have yet to be opened.
The same thing kind of goes for Champlain Valley as well. There is predicted of between five and 7% spore release, so maintain your desired fungicide coverage as well.
The big thing is to think about Finger Lakes actually this weekend as well as we have another 15% ascospores being predicted to be released. Make sure you make a single site application Friday before the rain. You could either do Cevya, Aprovia, Merivon, or any single site that you might think might work best for you. Most cultivars right now are in tight cluster, some are showing a little bit of a pink right now. There is no risk of fire blight, but keep monitoring them and maybe we’ll check back at the end of the week and update you on that as well.
And the last one I haven’t talked about yet is Long Island. Long Island survived a massive amount of ascospores being released this past weekend. I think it was close to like 45 or maybe up to 60% in some stations, but it looks like it’s a drier week this week for Long Island. There is some leaf wetness predicted this weekend, but currently there’s no infection event predicted, so just keep monitoring. We will probably check back in later this week.
State of the State with Anna Wallis
As always, the information I’m sharing are my own observations and aggregated from the regional specialists around the state. Remember that degree days are a measure of heat accumulation and a good indicator of pest activity and tree phenology early in the season. Insects are cold blooded, so their activity is directly related to the amount of heat they experience. Tree phenology similarly is well correlated with temperature and heat accumulation, although there are many other factors that also contribute to the activity of both.
For a quick reminder of how degree days are calculated, check out the video recorded by Art Agnello explaining the basic apple insect targets and IPM practices linked in the show notes. This video is part of a series that was created for the Apple IPM intensive workshop offered by Cornell in the New York State IPM program.
Apple IPM Intensive Workshop playlist: https://www.youtube.com/playlist?list=PLoNb8lODb49vifrm9Tla4GmAVhlIL0527
Apple Insect Targets and IPM Practices (including explanations of Degree Day calculations):
So after the warm temperatures last week, we accumulated tons of degree days for phenology early in the season. We’re keeping track of Degree Day base 43 Fahrenheit since January 1, and last week we had about 20 to 30 degree days per day and 100 to 150 over the course of the week, depending on the location. This is closer to what we might expect in a normal week in the middle of the summer in most of the state.
If last week was the week of heat. In Kerik’s words, the beginning of this week put everything on pause over the past three days. The total accumulated degree days is only between 10 to 20 degree days so far, but by the end of the week, temperatures are expected to increase again and phenology will pick up.
In the Hudson Valley and southern locations, pink lady opened some king blooms as early as Thursday last week, with quite a lot of bloom opening on Saturday and Sunday. From the unseasonably warm temperatures, McIntosh in Dutchess County were starting to open some kings on Monday. Cherries were in full bloom on Saturday in Ulster County, and a few peach blossoms that survived the February cold snap were up as well.
Honeycrisp remained behind in the Lake Ontario region. Fuji, Honeycrisp, and Gala were at the early tight cluster stages in inland and lake sites on Monday. Early pink of the King was noted on Gala and an inland site in Marion Wayne County. Remember, inland sites tend to be a little bit more advanced because they aren’t as moderated by the cool lake. However, this year many of the warm weather systems have been coming from the south rather than from our upper Midwest neighbors, so things are not that different in Geneva this week. Most apples are at tight cluster or open cluster in a few early blocks and varieties. I saw the first pink tissue in McIntosh this morning. Peaches are beginning to bloom. Cherries, plums, and apricots are in bloom. Most started to bloom Thursday or Friday last week.
In the Capital Region, growers are seeing tight cluster, possibly early pink. With the cooler weather, things should hopefully progress more slowly over the next two weeks, as we hope in the whole rest of the state too.
In the Champlain Valley, McIntosh in Peru is now at half inch green or more, with some cluster leaves beginning to unfurl. Honeycrisp is also at about a half inch or so on average.
In Macintosh, pink usually occurs at about 265 to 315 degree day base 43 and bloom at 340 to 415 as of the end of the day.
Tuesday, April 18 degree day accumulations across the state were as follows:
You can also find the average degree day ranges correlated with phenology and pest management in the Cornell guidelines.