Scaffolds 2024 Digest: Week 18
On this week’s episode of Scaffolds, I talk about starting to think about BMSB or brown marmorated stink bug. Kerik talks about apple scab symptoms on the fruit versus the leaves and disease forecasting for Marssonina, powdery mildew and fire blight. And last, Anna gives us our state of the state update on degree day accumulation and trap captures.
Monique Discusses Brown Marmorated Stinkbug
Monique: Well, everyone, it’s that time of the year. It’s time to start thinking about brown marmorated stink bug. We are headed towards harvest, barreling towards harvest even, and this year has been more dry, I would say overall, than last year. So it could be a year where we see a lot of stink bugs, but can’t be sure yet. Obviously in the Hudson Valley there is the most intense pressure for this insect. However, it can strike at any time, but it’s particularly bad on later varieties. So if harvest goes quickly, then maybe this won’t even be as much of an issue because the fruit won’t be in when they move in, but I’m assuming that they are also moved up. However, there’s lots of other tasty things out there right now for them to be invading, such as sweet corn. When it comes to this insect, I think one of the key things to know is how to identify it, and there are some other species that look really similar. So there’s two other in particular brown colored species that you can easily mistake for a brown marmorated stink bug. The first one is the spined soldier bug, and this can be confused with BMSB, but it’s overall a beneficial insect and the key differences are that it has spined shoulders, meaning that it has like almost thorn looking shoulders, and this occurs with a black band on the primary wings at the abdomen end. BMSB has rounded shoulders and lacks this banded wing pattern. Spined soldier bug also is more it can be slightly smaller than BMSB, but if you don’t have a good search image for BMSB, then that’s not super helpful. But anyway, I think it’s important to know the difference between these two in particular because spined soldier bug is a very effective, well, effective predator on a variety of arthropods. Apparently, they feed on up to and maybe more than 90 different insect species, including Mexican bean beetle, European corn borer, diamondback moth, and more. The first instar nymphs of the spined soldier bug have a blackish head and a thorax with a reddish abdomen, which is similar to a BMSB first instar. But BMSB first instars have an orange or red abdomen, black head, and these dorsal stripes. So that’s one way you can tell the difference between the nymphs. In addition to this spined soldier bug, there’s another stink bug species, the brown stink bug, very creative name that also looks very similar to BMSB. And it also is a fruit feeding stink bug, and that can cause the same or trigger the same management strategies. It can cause deformities resembling a cat’s face in peaches. And this is similar to BMSB overall. So I think the main thing here is to know the difference between BMSB and the spine soldier bug to make sure you’re not mistaking this beneficial predator for the pest insect.
Figure 1: Spined soldier bug (Source: University of Kentucky)
Figure 2: Spined soldier bug (University of Florida Entomology)
Figure 3: Pentatomidae – Euschistus ictericus aka Brown stink bug (BugGuide.net)
When it comes to monitoring BMSB, there are some pheromone-based trapping methods. You know, a bunch of different traps out there, but typically what’s used is either a clear sticky card or one of those black pyramid traps. And apparently, Cornell has been monitoring BMSB since 2011 and their understanding of where they’re coming up across the state. However, we found in our work that the trap captures don’t necessarily correlate with in-field damage. I think in the late season, what we were overall getting a sense of from our work is that it’s really the late instars and in particular the adults that cause the most late-season damage. The nymphs, yes, you’re going to want to not have them mature in field when they’re still fruit.
Overall, I think the take home message here is that it’s time to start thinking about BMSB. Are they in your orchard? You know, have scouts take a look either beating cloths or with traps, and it’s not completely clear what the threshold is. However, if they start moving into your field and you want to target the looking at the edges, because they do move in on the edges, it can cause this pest can cause a lot of damage very quickly. So it’s really important to get that first detection. So even though the trap captures don’t necessarily correlate to infield damage, having the trap to tell you when they’re moving in the field, I think is a good approach. Of course, the main treatment for these insects when they are in the field are pyrethroids, which are very hard on natural enemies. So I think that the key is to maybe not spray if you don’t have them, but it’s about figuring out whether you have them or not. And that’s why I think those pheromone-based traps are good and getting them out before the fruit is completely mature to see if you’re getting any detections early on. So putting them on now, since we’re probably a good month from harvest, some varieties three weeks or less too. So depending on where your apples are in their maturity and thinking about getting traps up and then remembering that they are particularly attracted to Honeycrisp, this has been throughout the literature, so being sure to keep a special eye on those blocks and blocks that are along wooded edges. And that’s all I have for this week, and I will talk to you guys again next week.
State of the State with Dr. Anna Wallis
Anna: 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 always, I’m Anna Wallis with the New York State IPM program at Cornell and I’ll be sharing information aggregated from the regional specialists and my observations.
Starting with a quick recap of the month of July, extreme weather has been the theme. Heat and humidity, storms and drought have been recorded across the northeast. This past week, Monday and Tuesday primarily, a front moved across the upper Midwest and northeast and there were numerous tornado, severe wind and other severe weather reports. In New York. Tornadoes were significant, perhaps the most tornadoes in a single month on record, but that’s still just preliminary data according to the NOAA Storm Prediction center and the Northeast Regional Climate Center. High wind and hail reports were concentrated in western New York, the Lake Ontario Region and in the Capital Region. There were specifically storm reports on the NOAA Storm Prediction center or hail reports in Genesee, Ontario, Courtland, Erie, Madison, Herkimer, Oneida, Hamilton, Saratoga and Warren over Monday and Tuesday. This is following the previous week of extreme rainfall recorded in many places in New York, Vermont, and New Hampshire with flash flooding and up to three to seven inches of rainfall due to Hurricane Beryl that came through on July 11. In other parts of the region in the northeast, states such as Maryland, West Virginia and Pennsylvania are reporting extreme drought. So overall extreme weather across the northeast after the beginning of the week last week with the extremely hot severe weather, we had a quick break in the weather with cooler temperatures; Highs went from being in the upper eighties to in the seventies [°F] for most of the state. Precipitation was again sporadic across the state. In some locations, two to three inches were recorded over the course of last week, but in other places, less than a 10th of an inch was recorded. Looking at the forecast going forward for this week and next, unfortunately, we’re back to excessive heat and humidity. Both the six-to-ten and eight-to-14-day outlooks in the NOAA Climate Prediction Center are predicting above average temperatures again and near normal to slightly above average precipitation. The long-term forecast for the rest of the season also continues to predict hotter than average and wetter than average weather, and that’s for the months of July, August, and September leading up to and through apple harvest.
Looking at phenology across the state now, we’re mostly at terminal bud set on most apple varieties, although we do see some new growth after all of the rainfall. Fruit is continuing to size and color well and most people are focusing on getting cover sprays on in between the rain and wind events. As we’ve reported the past few weeks, because of the early season and hotter than average season, we’re expecting a slightly earlier than normal harvest. Be sure to be paying attention to your phis, your pre harvest intervals as you’re selecting materials at this point in the season. In addition to apples, peaches, plums, and the last of cherries are now harvesting; Blueberries continued harvest; Raspberries are near the end and other berries are either ripening quickly or finishing up harvest accelerated by all the rain and the hot conditions.
Now, looking at some upcoming pest events, apple maggot is one of the primary insects that we’re paying attention to now. We’re continuing to get reports of catches on red sticky spheres at this point in the season in many locations in the state. In many locations we are not at threshold or no trap captures have been reported. But in some problem areas, trap captures are significantly over the thresholds. So early in the season, we monitor for apple maggot using yellow sticky cards as the adults emerge. But at this point in the season, we’ve moved to using red spheres with a coating of the sticky tangle foot, which is to capture ovipositing females. So the threshold for those traps is five per baited trap or one to two per unbaited trap.
Codling moth and OFM second generation are also insects that we’re paying attention to at this time. Typically, these insects emerge their second generation and we see a flight in our trap captures. And then we use those biofixes for the second generation to predict egg hatch and larval emergence. If you’re using that second generation biofix, we would time our insecticide applications to 200 to 250 degree days base 50 after that second generation emergence of the moths. Or you can use the first generation emergence or biofix in the spring to predict the second generation. So if you’re using your first generation biofix, that would be about 1200 to 1300 degree days base 50 after that first generation biofix. In both situations in the Hudson Valley, we’re expecting that larval emergence at this time and in the Capital Region in Western New York, perhaps a couple of days later, and then a few days after that in the Champlain Valley. It’s important for both of these insects with multiple generations per season that we’re rotating chemistries. So make sure that you’re using a different mode of action to make sure that you’re managing resistance to pesticides in your orchard.
For oblique banded leaf roller trap captures are now very low and insects are too large for management. We’re also continuing to see mite activity in orchards.
So European red mite and two spotted spider mite that can cause brown bronzing in the canopy. And then you can look closer and see some of the rasping or kind of speckled feeding on the newest leaves. We’re also seeing a lot of natural enemies, including predatory mites and lacewing larvae in the canopy that are helping combat those insects.
Woolly apple aphid continues to be active this season. We’re seeing colonies increasing both on old pruning cuts and continuing to move out to leaf axles. Many of the places that we’re scouting, we’re also seeing active parasitism. So we’re seeing small black aphid mummies with circular exit holes where the aphid has been parasitized by parasitic wasps.
Brown marmorated stink bug and other stink bugs are active at this time in the season. This is the second generation of most of these stink bugs and that nymphs are active now. We’ve seen feeding on peaches, which can look like cat-facing sort of an indent in the fruit. We haven’t seen very much damage on apples yet. It’s still a little bit early. Remember that they tend to move in from other places, so if there’s a cornfield or something nearby your orchard that gets harvests, they will quickly jump over to the nearby crop. You can be monitored monitoring for brown marmorated stink bug using a tedders trap. The threshold for those tedders or pyramid traps is ten traps, ten insects per week. Or there are also clear sticky panels, and these don’t have an official threshold, but we recommend three to four insects per week. We’ve had a couple of reports of European corn borer, which is a sporadic insect in orchards. The damage can look like wilting shoot tips, which can easily be confused with fire blight. But if you look for the inconspicuous entry holes that are usually hidden deep in the axles of the newest leaves, you can see a little bit of a hole and frass, and then if you cut it open, you can see the inside. And that’s an easy way to distinguish European corn borer. OFM can also cause similar feeding, typically more early in the season that shouldn’t be confused with other things that can cause wilting, like fire blight.
Speaking of diseases, this season, fire blight continues to be relatively tame, so knocking on wood or crossing fingers. Aside from a few known problem areas in New York, we haven’t heard too many reports. If you do have reports of fire blight, be sure to submit a sample to Kerik Cox’s lab.
We are continuing to see scab lesions popping up in commercial orchards. It was a particularly tough scab season this year and so keep on the lookout for secondary scab.
Powdery mildew appears to have calmed down a little bit, at least for now. This pathogen can’t survive in free standing water, so after all the rain, it seems to be a little bit less.
Sooty blotch and fly spec we continue to be on the lookout for this disease complex, with all the rain we’ve had this season and there have been plenty of infection events.
We’ve seen a few sporadic fruit rots, primarily bitter rot, showing up in a couple of places. You can be looking for growing brown circular lesions, often with concentric circles, and orange fruiting bodies developing. If you cut the fruit in half through the lesion, it will also look v-shaped.
We’re also seeing a lot of frog eye leaf spot or Botryosphaeria, particularly in the Hudson Valley, which can look like lesions that are defined and circular, somewhat depressed on leaves, and these often have very small black fruiting bodies in the center of those lesions. We’re also starting to get more reports and observations of yellow leaf spotting, so this is often Marssonina, glomerella or necrotic leaf blotch, can also be related to many forms of phytotoxicity. So if you would continue sending us your photos so we can help you with diagnosis and just be aware of what’s going on around the state.
Also around this time we start to see more tree decline, and so there are lots of reasons why trees can decline and collapse. We usually start to see this as trees get closer to harvest and they’re supporting so much fruit growth. Dr. Jason Londo at Cornell is doing a lot of research on this along with his student Ken, and so they have a survey out that is meant to collect information and reports of tree decline, and we’re asking you to complete that survey. That’s being distributed in regional newsletters from extension teams, and we’ll also include the link in the show notes.
Looking quickly at berries and cherries, spotted winged drosophila trap captures continue to climb in many places. This is typical of this insect – once the populations get established or are present for the season, we see the populations accelerate really rapidly. In some places, trap captures are still relatively low due to the harvest of a certain crop or sufficient management by insecticides and other practices. The first trap captures were reported in Franklin and St. Lawrence counties last week and the previous week. This is interesting because it’s similar to last season, 2023. So compared to most of the rest of the state, 2024 trap captures were early in most locations and for probably environmental reasons, and the specific locations where we’re monitoring trap captures in Franklin and St. Lawrence were similar in 2023 and 2024. Again, if you want to continue to get updates about spotted wing drosophila and other berry pests, and if you’re a cherry grower that’s interested in getting spotted wing drosophila updates, we would like you to subscribe and confirm your email for the new Berry Pest monitoring network blog where you’ll get reports for spotted winged along with other berry pests including cherry fruit worm, cranberry fruitworm and blueberry maggot.
And now here are the current degree days from the major fruit producing regions throughout the state. Throughout the season, we’ve been aligning this information with previous work done by doctor Art Agnello relating to McIntosh phenology and degree days base 43 Fahrenheit. As of July 22, the degree day accumulations base 43 were Geneva 24 35; Highland at the Hudson Valley Research Lab, 2603; Clifton Park, 2444; Peru 21 51; Medina an Inland site 2355; Appleton North a Lake site 2207; Fairville an inland site 2312; and Williamson a Lake site 2344. As always, you can see this information and a list of upcoming pest events in the show notes. That’s all for this week, and good luck until next week.
Phenology & DDs for NY NEWA Stations from 1/1 – 7/22
Station || Stage || DD 43F || Rainfall (in)
Geneva || fruit sizing || 2435 || 1.37
Highland (HVRL) || fruit sizing || 2603 || 1.97
Clifton Park || fruit sizing || 2444 || 1.31
Peru (Forrence) || fruit sizing || 2151 || 1.6
Medina – Inland || fruit sizing || 2355 || 1.26
Appleton North – Lake || fruit sizing || 2207 || 0.67
Fairville (The Apple Shed) – Inland || fruit sizing || 2312 || 1.48
Williamson (DeMarree) – Lake || fruit sizing || 2344 || 1.9
*all DDs Baskerville-Emin, B.E
Upcoming Pest Events
Pest/Phenology Event || DD Base 43˚F || Approx. Date
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
OBLR Summer Gen. 1st Sample || 10-Jul ± 5 days
STLM Summer Gen. 1st Sample || 9-Jul ± 7 days
RBLR – 2nd flight starting || 1367 ± 105 || 29-Jun ± 6 days
AM – 1st catch || 1509 ± 285 || 4-Jul ± 12 days
Lesser peachtree borer – peak catch || 1234 ± 470 || 25-Jun ± 19 days
STLM – 2nd flight peak || 1563 ± 207 || 6-Jul ± 8 days
Codling moth – 1st flight ending || 1557 ± 262 || 6-Jul ± 12 days
Peachtree borer – peak catch || 1579 ± 465 || 7-Jul ± 19 days
Lesser appleworm – 2nd flight starting || 1768 ± 339 || 14-Jul ± 12 days
OFM – 2nd flight peak || 1450* ± 147* || 11-Jul ± 9 days
American plum borer – 2nd flight starting || 1850 ± 290 || 16-Jul ± 11 days
RBLR – 2nd flight peak || 1721 ± 232 || 13-Jul ± 7 days
San Jose scale – 2nd flight starting || 1804 ± 170 || 15-Jul ± 8 days
Codling moth – 2nd flight starting || 1887 ± 313 || 20-Jul ± 13 days
Dogwood borer – peak catch || 1611 ± 226 || 8-Jul ± 10 days
STLM – 2nd flight ending || 2167 ± 177 || 28 Jul ± 8 days
American plum borer – 2nd flight peak || 2290 ± 285 || 1-Aug ± 8 days
OFM – 2nd flight ending || 2044* ± 233* || 31-Jul ± 7 days
ERM Sample – 7.5 mites/leaf || 1-Aug”
Cherry fruit fly traps in || 1-Aug
San Jose scale – 2nd flight peak || 2312 ± 174 || 3-Aug ± 9 days
Apple maggot – peak flight || 2394 ± 247 || 6-Aug ± 10 days
Codling moth – 2nd flight peak || 2327 ± 349 || 6-Aug ± 13 days
RBLR – 2nd flight ending || 2419 ± 273 || 7-Aug ± 10 days
STLM – 3rd flight starting || 2420 ± 196 || 6-Aug ± 7 days
Comstock mealybug – 2nd gen. crawlers emerging || 2429 ± 195 || 8-Aug ± 12 days
OBLR –2nd flight starting || 2413 ± 201 || 7-Aug ± 9 days
OFM – 3rd flight starting || 2275* ± 290* || 9-Aug ± 9 days
Lesser appleworm – 2nd flight peak || 2607 ± 463 || 15-Aug ± 23 days
RBLR – 3rd flight starting || 2715 ± 214 || 19-Aug ± 10 days
STLM – 3rd flight peak || 2755 ± 222 || 19-Aug ± 9 days
OFM – 3rd flight peak || 2625* ± 137* || 27-Aug ± 12 days
*Base temperature for OFM 45F
Apple Tree Decline Survey
Apple decline research is hindered by an incomplete understanding of where it is occurring and what its symptoms look like on different rootstock/scion combinations. Please consider taking this survey, even if you haven’t observed apple decline in your orchard blocks! Your participation will help drive research focus in the right direction and aid in the creation of informative extension documents. https://forms.gle/NpRkDEZmTB6EPUh98
Virtual Orchard Scout Training #1
https://www.youtube.com/watch?v=OtyOWCL1Q2A
Virtual Orchard Scout Training #2
https://www.youtube.com/user/NYSIPM
Berry Pest Monitoring Network – NEW Blog!
https://blogs.cornell.edu/berrypests/
Quick Guides for SWD Management
https://fruit.cornell.edu/spottedwing/management/
https://fruit.cornell.edu/spottedwing/
NOAA NWS Storm Prediction Center
https://www.spc.noaa.gov/
U.S. Drought Monitor
https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?Northeast