Scaffolds 2024 Digest: Week 11
This post is a text digest of the Scaffolds Podcast. To listen to the original episode, visit the following link: Scaffolds Podcast on Spotify
On this week’s episode of Scaffolds, I talk about Apple Maggot, which should be showing up sooner than later. Kerik gives us insight on continued disease management, and Anna gives us our state of the state update on degree day accumulation and trap captures.
Entomology with Monique Rivera
This week I have a relatively quick update. So first I wanted to talk about the 2024 Virtual Orchard meetup series. The first one is going to be held on Thursday, June 6 at 07:00 PM. The topic for this first meeting is going to be water wisdom, navigating tree fruit production through drought and deluge. This is a joint effort between Michigan State University, the Cornell Cooperative Extension Lake Ontario Fruit Team and Washington State University. Pre-registration is not required to attend and I’m going to include the Zoom link in the show notes.
So, we’re heading into the part of the season where we need to start thinking about apple maggot flies, and I think that I have a bit of a longer, maybe not time-wise long, but a long bit of information to share with you specifically about apple maggot. So I think we’re expecting the first appearance of apple maggot flies in wild apple trees and abandoned orchards in Eastern New York shortly. I think that in Western New York we’ll see them a little bit later. But this all depends on temperatures and rainfall over the next week or two.
So, the ideal way for crop scouts, consultants and growers, if they’re interested in doing this on their own, is to use traps to monitor for these apple maggot populations. This approach is not always recommended in some cases. So some orchards, if they have really high populations which require regular sprays, then what’s the point of trapping, right? Some orchards have really low populations, rarely needing sprays. So, as with most pest issues, it’s going to be important to understand the nature of your farm. And lastly, most commercial New York orchards have moderate or variable pressure, which can make this monitoring critical for timing sprays.
So, in order to detect apple maggot, yellow sticky cards have been used for over 50 years. These panels are helpful in detecting the presence overall of apple maggot flies. And what we expect is that the flies should be emerging from hibernation from the soil anytime in mid-June to early July in New York. Again, this really depends on soil temperature and overall weather, but I think we’re overall a bit pushed up this season, so it’s time to start thinking about it now. And during the first seven to ten days of their adult life, they feed on aphid honeydew and then become sexually mature. And after they’re sexually mature, they are attracted to those yellow sticky panels, and they see them as sort of these super leaves during the early stage. A few panels in an orchard can serve as an early warning device if there’s a likely apple maggot emergence site nearby. So again, those wild apples or abandoned orchards. Many flies spend time outside the orchard before searching for fruit to mate and lay eggs, making these advance warning traps somewhat difficult to use for their exact purpose. But a single catch of a sexually mature fly means an immediate spray is needed, and you could pose a major risk to your crop if you aren’t checking those traps daily in that case.
There are also some other trap options which could be arguably more effective. So, there is this red apple looking or red sphere trap shaped like a quote unquote “super apple.” And this helps to catch flies early. And allowing for twice weekly checks, there’s a one-to-two-day response time before spraying with those traps. Research shows that these traps can use a higher threshold than the traditional yellow panels with five flies per trap as the new threshold for spraying. So it’s recommended to hang three volatile baited spear traps in a 10 to 15 acre orchard on the outside row, facing any probable apple maggot migration direction. So, an example would be if you have an orchard that’s backed up to a woodlot where you know there are wild apples or an abandoned orchard, this might be the way to deploy those traps.
So, the point of hanging traps is to check them. I know it sucks. It’s not fun. Uh, feels like a frivolous activity. But if you make the effort to put them out, checking them periodically and spraying when the average catch per trap is at five or more apple maggots captured. And I think for this, you know, another key thing is that the proper identification of apple maggot is critical. And there’s tons of resources for this online.
If you have a home apple planting, you can try trapping out local apple maggot populations with these red sphere traps. And this can moderately protect fruit. It’s not going to guarantee that you will not have apple maggot damage. So one of these sphere traps is recommended per 100 to 150 apples. There are a bunch of different types of traps and lures available. So permanent sphere traps, which are wood or stiff plastic; disposable sphere traps, which are a flexible plastic, are just two examples. So the disposable traps last one season and are cheaper. And there are other traps that you use from year to year that can be more difficult to clean and more time consuming. And you can get apple volatile lures for use with any trap.
So I think that’s the next pest on our radar to be thinking about. Next week, I’ll be joined by Anna Wunsch to talk about viruses in apple trees. So, looking for that discussion next week. See you then.
State of the State with Dr. Anna Wallis
And now for the state of the state, your weekly roundup of phenology and degree day accumulations from the major fruit production regions of the state. As usual, I’m Anna Wallis from the New York State IPM program at Cornell, and I’ll be sharing information aggregated from the regional specialists across the state.
Now that we’re moving into June, let’s have a quick look back at the spring and the month of April. It’s been a record warm spring all three months; March, April, and May have been warmer and wetter than average. Pretty soggy in some places. Over the month of May, 2 to 3 inches were recorded at most NEWA weather stations, and in April 3 to 4 inches were recorded. Last week was somewhat warm, but not quite as hot as the previous week. High temperatures earlier in the week were only up in the upper sixties [°F] in many places, and then in the upper seventies by the end of the week. Relative humidity was very high across most of the state in most of the week. Precipitation that was recorded at most NEWA weather stations ranged from a quarter of an inch to a full inch, mostly recorded earlier in the week, Monday and Tuesday [May 27-28], with some sites mostly in the Hudson Valley and some lake sites recording precipitation on Thursday last week in the forecast, both the 6 to 10 day and 8 to 14 day outlooks on the NOAA Climate Prediction center are predicting normal to slightly cooler than average temperatures, and wetter than average conditions. Rain is expected for most of the rest of the week, in most places throughout the state for the latter part of this week, and that’s probably good timing [as] we haven’t had much rain for the past few days.
Phenology across the state now. We continue to be well ahead of degree day averages across the state, mostly owing to that really warm period a couple of weeks ago in the early spring. With the warm weather and the wet conditions, we’ve seen a huge increase in activity in both phenology and in pest complexes. We’re concluding the thinning window in most places in the state, wrapping it up, maybe in the northern part of the state, and so most people are wrapping up their thinning sprays and beginning to think about return bloom sprays. In the Hudson Valley, apples are between 20 to 30 mm, depending on variety, location and the amount of thinning that’s been done. Cherries are starting to color. Peaches and nectarines are also sizing nicely. In Western New York, the Lake Ontario region, Geneva, and similarly in the Capital Region, fruit is pretty similar, maybe slightly smaller. Fruit is ranging from 20 to 25 end of the thinning window. In the Champlain valley, we’re approaching 20 mm in many places and varieties, also near the end of the thinning window.
Looking at some upcoming pest events, we have a long list to report today, starting with plum curculio. We’ve seen a lot of activity in unmanaged or lower managed areas. The insects tend to move into the orchard starting at petal fall. As we’ve reported in the past couple of weeks of the podcast, at this point in most of the state, we have reached the end of that window and they’re moving into the orchard. That’s typically around 308 degree days, base 50, after petal fall. And so at this point, most of those insects have moved into the orchard and cover sprays should have been able to manage them.
Looking at some of the lepidopterans, both OFM and codling moth flights are ending in many places. And so now is a good time, this week, early in this week, or at the end of last week, sort of the window opened for insecticide application, targeting larvae, in northern locations, that might be toward the end of this week. That’s typically around 200 to 250 degree days base 50 after the biofix. Obliquebanded leafroller trap captures have been recorded in a few different places. It’s our second week in a row in a couple of Hudson Valley sites, and so we know these insects are beginning to be active, but it’s a little bit too early to be applying any insecticides targeting summer larvae yet.
We’re seeing more and more aphid activity, both green apple aphids and rosy apple aphids, as well as woolly apple aphids. Remembering that the green apple aphids will typically be on the shoot tips and kind of curling the leaves backwards. Rosy apple aphids tend to curl the leaves quite a bit more and sometimes can turn them pink, so they can be pretty easy to spot. Woolly apple aphid we’re still seeing mostly on old pruning cuts, usually two or older year pruning cuts, typically around the vascular ring that you see on that cut. Typically, we’re finding them with wool. This week we’re getting the first reports of woolly apple aphid moving out into those leaf axils, so be looking for that.
We’ve been seeing a little bit of tarnished plant bug injury, just a small amount of feeding this year. They’re usually more of a problem when it’s a dry season. So the insect will be looking for some kind of water source. And that injury again looks like sort of dimples in the fruit. We’ve been seeing and having reports of leaf hopper damage and saw fly damage. Leaf hopper damage is going to look like curling back of the newest leaf tissue and sometimes yellowing along the edge. At this point in time, sawfly damage looks similar to lep internal fruit damage, with boring into the fruit and then frass coming out of those holes. So you can be looking for that damage.
San Jose scale crawlers are expected to be active around this time, too, so if you’re monitoring for those crawlers using double sided tape around the trunk or a limb near an active infestation, you can be checking those traps now, for crawlers. Now is a good time to begin sampling for European red mites. Beginning in June we use a threshold of two and a half mites per leaf, and we use sequential sampling to determine whether any action is needed for management. So you would start by sampling 20 leaves for each from five trees and inspecting each of them to see if there’s presence or absence of mites. And so you’d use two and a half mites per leaf as present and anything less would be absent. Next, you could use the mite sampling chart in the Cornell guidelines to determine if you have enough leaves with presents to warrant action or if you should continue sampling.
Apple leaf curling midge is a pest that’s becoming more and more of a problem in some locations throughout the state. We’ve been seeing it for a couple of weeks now. It tends to curl the leaves back pretty aggressively, and then they get a little bit brittle. So you can uncurl those leaves to see the nymphs, which turn bright orange before they pupate and fall to the ground.
Moving into diseases, we are getting the first reports and observations of fire blight strikes in Eastern New York, in a couple of places in the Hudson Valley and in the Capital Region. You can be sending samples to Kerik Cox’s lab for testing for streptomycin resistance, and we encourage you to do that. Primary scab season is finished for the season, but we are detecting abundant lesions in unmanaged places and in a couple of managed blocks, so be vigilant looking for those to make sure that you don’t need to be on top of managing secondary scab, especially with the cooler, humid weather. It can quite easily get out of hand, and more spores can be available for infection. We’re continuing to see a lot of powdery mildew across the state. It’s becoming more and more prevalent with the continued warm, humid weather, so be looking for that. Rust is also becoming more prevalent, so you can be looking for the bright orange sporulation on leaves. We’re seeing frog eye leaf spot or black rot lesions on leaves now too. And we’re beginning to see the very earliest sooty blotch and fly speck so you can be inspecting your fruit for summer diseases and making sure to stay on top of your management for those summer diseases.
Looking at cherries and berries we’re continuing to monitor for spotted wing drosophila across the state and we have had our first trap captures across much of eastern New York from the Hudson Valley up into the Capital Region. The trap captures have been in really low numbers, between two and five or eight insects per trap in both jar and sticky red cards, so we know that that insect is present and most of these traps have been in fruit that is still unripe. Just a reminder that we are switching over to a new blog. This is the berry pest monitoring network and we’ve sent a couple of different blog posts reminding people to switch over. We are continuing to cross post first trap captures and other blog posts to both the new blog and the old spotted wing drosophila blog. But we encourage everyone to move over to the new blog so that you can be sure to be getting the most accurate information. We encourage both berry growers as well as cherry and grape growers to subscribe too, if they’re interested in getting updates about spotted wing drosophila. And as you’re selecting your insecticides for managing this insect, we have posted the quick guide for insecticides on the Cornell Fruit Resources page as well as the regional fruit team websites so you can be using that quick guide to select insecticides and rotate insecticides to help manage resistance.
And now here are the current degree days in major fruit producing regions across the state. Throughout the season we’ve been aligning this information with previous work done by Art Agnello relating to Macintosh phenology and degree days base 43. In Geneva, we’re currently at 1046; Highland at the Hudson Valley Research Lab, 1126; Clifton Park, 1006; Peru 840; Medina, an inland 1022; Appleton North, a lake site 895; Fairville, an inland site 961; and Williamson, a lake site 958.
That’s all for this week and good luck until next time.
| McIntosh Phenology and DDs (43F BE) (avg +/- std) | |
| Phenological Stage | DD Accumulation |
| Silver tip | 58-106 |
| Green tip | 99-144 |
| Half-Inch Green | 150-201 |
| Tight Cluster | 206-257 |
| Pink | 267-316 |
| Bloom | 344-415 |
| Petal Fall | 439-523 |
| Phenology & DDs for NY NEWA Stations from 1/1 – 6/3 | ||
| Station | DD Accumulation | Stage |
| Geneva | 1046 | Fruit Sizing |
| Highland (HVRL) | 1126 | Fruit Sizing |
| Clifton Park | 1006 | Fruit Sizing |
| Peru (Forrence) | 840 | Fruit Sizing |
| Medina – Inland | 1022 | Fruit Sizing |
| Appleton North – Lakeside | 895 | Fruit Sizing |
| Fairville (The Apple Shed) – Inland | 961 | Fruit Sizing |
| Williamson (DeMarree) – Lakeside | 958 | Fruit Sizing |
Phenology & DDs for NY NEWA Stations from 1/1 – 6/3
Station || Stage || DD 43F || Rainfall (in) week past || Rainfall (in) May
Geneva || fruit sizing || 1046 || 0.32 || 2.23
Highland (HVRL) || fruit sizing || 1126 || 0.98 || 3.8
Clifton Park || fruit sizing || 1006 || 0.6 || 2.93
Peru (Forrence) || fruit sizing || 840 || 0.41 || 2.37
Medina – Inland || fruit sizing || 1022 || 0.35 || 3.17
Appleton North – Lake || fruit sizing || 895 || 0.49 || 1.9
Fairville (The Apple Shed) – Inland || fruit sizing || 961 || 0.25 || 2.1
Williamson (DeMarree) – Lake || fruit sizing || 958 || 0.39 || 1.91
*all DDs Baskerville-Emin, B.E
Upcoming Pest Events
Pest/Phenology Event || DD Base 43˚F || Approx. Date
ERM Sample – 2.5 mites/leaf || 1-Jun
OBLR traps set out || 1-Jun
Black stem borer – 1st flight peak || 681 ± 170 || 1-Jun ± 9 days
RBLR – 1st flight ending || 753 ± 140 || 2-Jun ± 8 days
American plum borer – 1st flight peak || 784 ± 183 || 3-Jun ± 9 days
Codling moth – 1st flight peak || 768 ± 206 || 3-Jun ± 12 days
STLM – 1st flight ending || 813 ± 128 || 5-Jun ± 9 days
OBLR – 1st adult catch || 884 ± 90 || 9-Jun ± 6 days
OFM – 1st flight ending || 825* ± 126* || 12-Jun ± 8 days
Peachtree borer – 1st adult catch || 1032 ± 266 || 15-Jun ± 11 days
San Jose scale – 1st flight ending || 1039 ± 182 || 16-Jun ± 8 days
Black stem borer – 1st flight ending || 1056 ± 198 || 19-Jun ± 9 days
STLM – 2nd gen. 1st adult catch || 1063 ± 91 || 16-Jun ± 6 days
San Jose scale – 1st crawlers observed || 1124 ± 91 || 19-Jun ± 8 days
Dogwood borer – 1st adult catch || 964 ± 230 || 12-Jun ± 9 days
American plum borer – 1st flight ending || 1344 ± 144 || 29-Jun ± 7 days
Apple Maggot Traps Set Out (in orchard) || 1-Jul”
ERM Sample – 5.0 mites/leaf || 1-Jul
Comstock mealybug tape traps set out || July 1 (ENY), July 15 (WNY)
OFM – 2nd flight starting || 1180* ± 136* || 29-Jun ± 5 days
*Base temperature for OFM 45F
NEWA Help Desk Frequently Asked Questions and Table of Contents. https://help.nysipm.org/hc/en-us/categories/16994462926231-NEWA-Network-for-Environment-and-Weather-Applications
Quick Guide for Apple Insect Pests https://help.nysipm.org/hc/en-us/articles/23290226665751-NEWA-Quick-Guide-for-Apple-Insect-Pests
NY Tree Fruit Pest Monitoring Network
https://blogs.cornell.edu/treefruitpests/
Interested in collaborating and contributing trap capture data? Contact Anna Wallis aew232@cornell.edu
Berry Pest Monitoring Network – NEW Blog!
https://blogs.cornell.edu/berrypests/
Quick Guides for SWD Management