Weekly Update 8/12/2025

This is the fourteenth post of the 2025 season for the Tree Fruit Pest Monitoring Network. This will be the last regular post for the 2025 season! Monitoring will continue as collaborators are able up to harvest, with blog posts as needed. Look for more detail and regionally specific management recommendations from your local CCE and regional teams.

Weather and Phenology across the state now

Tree fruit crops continue to look excellent leading up to harvest across NY. In orchards throughout the state, apples continue to size and color. Trees have mostly reached terminal bud set, in which the trees stop growing new leaves and shoots, and begin to move toward harvest and fall rest. Hand thinning continues. Summer pruning and reflective fabrics are being applied to increase fruit color in some locations. Stone fruit harvest is well underway in most of the state.

As we near harvest, regional teams have started producing weekly maturity reports. Sign up for these updates for regional and variety-specific information. Comparisons of DD accumulations and seasonal conditions indicate predicted harvest will be slightly later than the last two seasons, particularly in WNY. Generally, across the state DD accumulations are slightly behind the 2024 season and considerably behind 2023, both of which were very early harvest years compared to averages. At this point in the season DD Base 39F from 4/1 to present is used to make comparisons. In WNY Craig Kahlke is predicting an average of ~6 days behind 2024, with inland sites closer to last year (about 2 days behind) and lake sites being up to 10 days behind. Using Craig’s approach, we also compared DD accumulations in other regions. In the Hudson Valley, degree day accumulation is similar to last season, approximately 2 days behind. The Capital Region and Champlain Valley approximately 5 days behind as well.

DD Base 39F Accumulations for 2025 and 2024 from 4/1 to 1/1  

Over the past two weeks, most of the state experienced a slight cooling trend followed by a return to very hot conditions with very minimal rainfall. Scattered storms and a cool front around the end of July brought cooler weather and isolated rain, with accumulations of >1″ in the Hudson Valley, nearly 3/4″ in the Capital Region, and several tenths of an inch in other locations, while other places recorded less than 1/10 during this period. Aside from this event, insignificant rainfall has been recorded across the state. Irrigation is critical as crops continue to approach harvest to facilitate fruit sizing.

Hot weather continues this week. In the Hudson Valley, highs are in the 90s (F) and heat advisories were issued again. Highs in the rest of the state are reaching into the low 90’s, and lows are predicted to be in the 60s. These hot temperatures are less than ideal approaching harvest, especially concerning coloring. Temperatures are expected to cool off at the end of the week to mid 70’s or 80’s, with potential rainfall of nearly 1/2″ in most locations on Saturday, and some isolated storms during the week. Long term forecasts by the NOAA Climate Prediction Center indicate a possible change in this trend. Both 6-10 and 8-14 day outlooks anticipate cooler than average temperatures, less than average precipitation is still expected.

Extreme weather the month of July appears to be a pattern. The Northeast Regional Climate Center indicated there was extreme precipitation across the region in 2025, either in the form of drought with some places reporting one of the hottest and driest on record, and other locations reporting as much as 234% of normal rainfall. A list of events over the past decade summarized other extreme weather events in July for the Northeast.

Approximate apple phenological stages recorded in locations across NY State 

Record these biofixes for your orchard!

Phenology & DDs for NY NEWA Stations from 1/1 – 8/11

*all DDs Baskerville-Emin, B.E

Upcoming Pest Events

Fact sheets for tree fruit pests can be found on the Cornell IPM Fact Sheet website. More information on the NEWA Models can be found on the NEWA website and in this NEWA Quick Guide for Apple Insect Pests. 

Diseases

Summer diseases are of primary concern at this time. Symptoms of various fungal diseases are abundant in unmanaged locations, including Black Rot or Frogeye Leaf Spot, White Rot, Bitter Rot, and Sooty Blotch Flyspeck. Black typically begins as round brown lesions on leaves, with a purplish edge. Fruit may also be infected, beginning as small black spots, then encompassing the fruitlet, which will eventually turn into a mummy. White rot does not infect the leaves, fruit infection begin similarly as small spots, but the progress to rot the core of the fruit, and is typically lighter in color and very wet. Both over winter in damaged or diseased woody tissue. Bitter rot causes characteristic lesions on the fruit with concentric rings, and produces orange sporulation. We are observing abundant black rot foliar lesions, and early fruit spots of these rots in low managed orchard in the Hudson Valley, where there has been plenty of opportunity for infection and disease development with all the rainfall. Sooty Blotch and Flyspeck are superficial diseases, causing black to greenish diffuse spots on the surface of the fruit.

Leaf spot symptoms with various biotic and abiotic causes are being observed in many locations across the state. Symptoms may be caused by the pathogens such as Marssonina (apple blotch) and Glomerella (bitter rot), as well as physiological disorders such as necrotic leaf blotch, and other environmental injuries (yellowing due to excessive moisture and/or poor nutrition, chemical injury, and mechanical damage). It is critical to properly diagnose the damage observed to ensure effective management.

Powdery mildew continues to be active on new growth on terminal shoots. The hot humid conditions, which we are experiencing now, are ideal for rapid development of new infections. This disease will become less problematic as trees approach terminal bud set and stop producing new shoots and leaves. The pathogen typically infects the newest terminal shoots, and hardened off leaves are less susceptible. Continue to scout for secondary infections now, visible as powdery white sporulation on new shoot terminals.

Insects

Throughout the season, continue to be checking traps and recording the biofixes for economically significant insects. A biofix is a biological indicator, observed in the field/orchard, used to start model calculations. Many models use a unique biofix, which must be recorded at the particular location of interest. Examples include 50% green tip, first sustained trap capture of moths (e.g. 2 consecutive weeks of adult captures). Specific biofixes used in NEWA can be found online: https://newa.cornell.edu/default–biofix–dates/. 

Apple Maggot activity has been detected in all regions of the state since the beginning of July. Trap counts are variable, as this can be a sporadic pest. In some locations trap captures have increased rapidly over the past two weeks to over 40, while most locations in commercial orchards remain below threshold for managment. This insect typically emerges around the end of June in Geneva and starts laying eggs in fruit early in July. Red sphere traps coated with tanglefoot (sticky) and with an apple or pear essence lure should be set at the edges of orchards, especially in area where you have known pressure. Three traps are recommended. Management is recommended when you reach an average of 5 flies per baited trap or 1-2 flies per unbaited trap. Traps should then be cleaned and the counts and thresholds reset.

European red mite and Two Spotted Spider Mite infestations have been reported in many regions. The hot dry weather is especially idea for rapid generations of these insects, especially in areas where it is very dusty. Use the diagrams in the Cornell Guidelines for sequential sampling methods and thresholds for management. Now that we are in August, threshold for management is now 7.5 mites/leaf higher than June or July. Make sure to flip leaves over and use magnification to see these tiny insects!

Obliquebanded Leafroller flight of the summer generation is over in across the state. Biofix (first trap capture) was reported in many locations several weeks ago in most locations. Insecticides targeting larvae at 350 DD43 after the biofix. A second generation of OBLR is typically observed as this insect prepares to overwinter, with flight beginning in Geneva at approximately 2413 DD43 or approximately Aug. 7 +/- 9 days. This generation overwinters as young larvae, which become active early in the spring prior to bloom. This generation can be scouted for at Tight Cluster in apples, and can be managed with a Bt application where pressure has been high in the previous season.

Codling Moth second generation is active or wrapping up across the state.  Where first generation was managed successfully the second generation is of low concern, and trap captures are low. The flight of the second generation in Geneva typically begins around 1887 DD43, of July 20, with peak flight at approximately August 6 +/- 1-2 weeks. In the Hudson Valley, the second generation is primarily over, with peak flight about 2 weeks ago. Management should be in place this week in this region. In WNY and the CV, second generation moths peak flight is over and larvae are active. protection should be in place now.

When selecting materials for managing codling moth, rotate IRAC groups (Modes of action) for resistance management. Use the same mode of action for a given generation, rotate to a new MoA for the second generation.

Management timing for insecticides:

• Insecticides targeting eggs: 150–175 DD 50 after biofix (note, Rimon may only be used once per season in NYS)
• Insecticides targeting hatching larvae: 230–250 DD 50 after biofix
• Follow up 14 days later
• Second Generation larval emergence can be roughly approximated based on first generation: 1250-1300 DD after 1st gen. biofix.

Oriental Fruit Moth third generation flight is predicted soon. Where management of the first two generations has been successful, the third generation is very low concern. Third generation typically begins in Geneva at approximately 2275 DD45 or August 9 +/1 9 days. Throughout the state our trap captures remain low. Use the NEWA OFM Model to forecast when egg hatch will occur and time insecticides. Management typically coincides with petal fall and other insect management at this critical timing. An additional cover is recommended approximately 10-14 days after the petal fall application.

Management timing:

• 170-200 DD 45, hatch of first generation larvae around petal fall
• 1150-1200 DD 45, hatch of second generation (after first gen biofix), approx. late June in Geneva

Woolly apple aphid activity continues to be reported in many locations. Populations have begun moving out into the canopy over the past month. Look in axils of leaves, where leaf connects to a new shoot. Make sure to pull aside branches and look inside the canopy where these insects are well protected by the leaves and their woolly covering. There are some natural enemies, including a parasitic wasp that can lay eggs inside aphids, leading to a parasitized black mummy aphid with round exit holes.

Stink Bugs, including Brown Marmorated Stink Bug (BMSB) and several native stink bug species all are active at this time. These insects typically move into the orchard from the hedgerows. You can monitor with a tedder (pyramid) trap using the appropriate pheromone lures. For these traps, the management threshold is 10 insects/trap. A clear sticky panel trap with pheromone lures can also be used. Thresholds have not been formally developed, but we recommend a lower threshold, approx. 3-4/week. A 2019 management update can be found here: https://rvpadmin.cce.cornell.edu/uploads/doc_744.pdf  and a 2023 update in the Fruit Quarterly Fall 2024 Issue.

Spotted wing drosophila trap captures have increased dramatically in most places the past two-three weeks. Once this insect emerges, it is typical for populations of this insect to increase rapidly. It is important to be monitoring in your location because emergence can vary by year, weather, and location. You can also check for fruit infestation by using a salt flotation test for larvae in the fruit. Check the Berry Pest Monitoring Network for updates.

Cherry Fruit Flies including several native species and the invasive European Cherry Fruit Fly are active now. Begin management as soon as fruit begins to blush. The quarantine for ECFF now includes all of Cayuga, Erie, Genesee, Monroe, Niagara, Onondaga, Ontario, Orleans, Oswego, Senaca, and Wayne Counties. This update was made by the NYSDAM following trap captures in these counties in 2024.

Upcoming Phenology & Pest Events Table

Reference: Table 7.1.4. Degree-day accumulations (from Jan. 1) corresponding to selected fruit phenology and arthropod pest events. Cornell Tree Fruit Guidelines.

Additional Resources

Weather

Northeast Regional Climate Change Monthly Maps
https://www.nrcc.cornell.edu/regional/monthly/monthly.html

NOAA Climate Prediction Center (forecasts and outlooks)
https://www.cpc.ncep.noaa.gov/products/forecasts/

Sunburn

Fruit Quarterly Article on research at the HVRL, also explaining types of sunburn.
https://nyshs.org/wp-content/uploads/2016/10/Reig-Pages-5-10-from-NYFQ-Book-Fall-2016.pdf 

NEWA and Pest Forecasting

NEWA Help Desk Frequently Asked Questions
https://help.nysipm.org/hc/en-us/categories/16994462926231-NEWA-Network-for-Environment-and-Weather-Applications

NEWA Help Desk Apple Insect, Disease, and Crop Management Forecasts
https://help.nysipm.org/hc/en-us/sections/17011505301783-Apple-Insect-Disease-and-Crop-Management-Forecasts

Quick Guide for Apple Insect Pests
https://help.nysipm.org/hc/en-us/articles/23290226665751-NEWA-Quick-Guide-for-Apple-Insect-Pests

Apple IPM Intensive Workshop playlist:
https://www.youtube.com/playlist?list=PLoNb8lODb49vifrm9Tla4GmAVhlIL0527

Apple Insect Targets and IPM Practices (including explanations of Degree Day calculations):
https://youtu.be/NwyBAcvbpUs

Virtual Orchard Scout Training webinar recording on the New York State Integrated Pest Management Program (NYSIPM) YouTube channel.
https://www.youtube.com/watch?v=OtyOWCL1Q2A

Online Course, BF224: Tree Fruit Scouting.
https://smallfarmcourses.com/p/bf-224-tree-fruit-scouting