Weekly Report 5/8/2025 | NY Tree Fruit Pest Monitoring Network

This is the second post of the 2025 season for the Tree Fruit Pest Monitoring Network. Each week we’ll provide a short summary of trap captures and pest activity in orchards from across NY State. Look for more detail and regionally specific management recommendations from your local CCE and regional teams.

Weather and Phenology across the state now

Across New York, orchards are at various stages of bloom! In Highland at the Cornell AgriTech Hudson Valley Research Lab, bloom began on Friday 4/25 with a few King blossoms opening up. Average bloom date at the Hudson Valley Research Lab is approximately 5/2, with the earliest on 4/16 and the latest 5/16. We are currently nearing petal fall in that block and many other locations across the region, although there is still a considerable amount of viable bloom in many blocks and varieties. In Geneva at Cornell AgriTech, bloom is in full swing. Average bloom date in Geneva is 5/10, standard deviation of 6 days.

Last weekend and early this week, the entire state of NY experienced an extremely wet weather trend with nearly 2″ of precipitation recorded at most NEWA weather stations. Many people are taking opportunities with breaks in the weather to recover for disease management. Forecasts indicate a warmer, dryer trend going into the next two weeks across most of the state.

Approximate apple phenological stages recorded in locations across NY State

Record these biofixes for your orchard!

Location	Green Tip	1/2″ Green	Tight Cluster	Pink	Full Bloom	Petal Fall
Highland (HVRL)	3/30	4/7	4/16	4/21	4/26	5/7
Geneva	4/8	4/15	4/21	4/26	.	.
Clifton Park	4/8	4/15	4/20	4/26	.	.
Peru	4/15	4/23	4/28	.	.	.

Phenology & DDs for NY NEWA Stations from 1/1 – 5/5

Station	Stage	DD 43F	DD 50F
Geneva (AgriTech North)	Bloom	419	218
Highland (HVRL)	Early Petal Fall	559	311
Clifton Park	Bloom	424	227
Peru (Forrence)	Pink	325	156
Medina – Inland	Bloom	361	181
Appleton North – Lake	Bloom	290	134
Fairville (The Apple Shed) – Inland	Bloom	410	202
Williamson (DeMarree) – Lake	Bloom	355	165

*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

Apple Scab primary infection season is well underway. Infection events were indicated by the NEWA scab model over the weekend (5/3-4), with 20-30% ascospore discharge in most locations. Continuous, combined infection events lasted through Wednesday in many locations. The model indicates primary apple scab season is nearly over in both the Hudson Valley, but maintaining coverage a little longer is advised, particularly if there is any risk that primary scab was not fully controlled and secondary spores (conidia) may be present.

Fire blight is of risk wherever blossoms are open. Infections were indicated by the NEWA fire blight model over this past weekend as well. Temperatures have been sufficient for growth of the bacteria on the flowers, followed by ample rain and humidity needed to produce an infection event. The model now includes an option to enter streptomycin application date, to help indicate risk up to five days into the future.

Powdery mildew will likely become more active soon. The first symptoms have been observed in both the Hudson Valley and Western NY. However, after significant rainfall, risk should be much lower, as the pathogen cannot survive in free water. The first infections take place on new developing shoots and flower clusters, after emerging from buds, where the pathogen overwinters. Followed by secondary infections, visible as powdery white sporulation on new shoot terminals. Management for this disease should begin around second cover.

Rust diseases are very active now across the state, thriving in the ample rainfall. Cedar apple rust galls in cedar trees were very active in our scouting this week, with robust teliospores visible producing ample teliospores that can infect susceptible apple tissue at this point in the season.

Insects

Now is the time of year to be checking traps and recording the first 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/.

Oriental Fruit Moth biofix as been recorded in many locations throughout the state. If you have had a past history of damage and trap catches are high (>10/trap/week), specific management is recommended. 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. These caterpillars can cause damage to stone fruit in which adults lay eggs near fruit buds in fall of the previous season, then the first generation emerges and tunnels into terminals, causing flagging of terminals. In apples, OFM will tunnel into fruitlets, similar to codling moth, but does not feed on seeds.

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

Codling Moth first trap captures have been recorded in both the Hudson Valley and Geneva. Traps should be placed at approximately bloom to monitoring first adult flight. Then use the NEWA CM Model to predict when egg hatch will occur an when to time insecticide, after first ‘sustained’ trap capture (i.e. two weeks of consecutive trap captures) has been recorded.

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

Lesser Apple Worm is also active around the state. It is a minor fruit pest, but frequently captured in OFM traps. These moths may be slightly smaller and have a more defined, metallic wing pattern, compared to the dusty brown appearance of OFM.

Spongy Moth was also observed last week in the Hudson Valley. This is an uncommon pest of tree fruit, but in past seasons (including 2024) populations were significant enough in many locations to cause damage to leaf and even fruit tissue. People handling fruit or working in the orchard may also have an allergic reaction to the insects.

Tarnished Plant Bug has been observed in most of the state. These true bugs have piercing sucking mouthparts that they insert into the new flower buds to feed. You will find the insects or droplets of sap (clear or amber in color). White sticky cards can be used to monitor for these insects, placed along the border of plantings, where insects are emerging from overwintering sites in hedgerows. Recommended action threshold for management is an average of 3 TPB/trap over 5 traps.

Obliquebanded Leafroller overwintering larvae are present in many orchards. Look for very small green caterpillars in flower clusters and terminal leaves. You may see frass, feeding, and webbing together of leaf and floral tissue. Trapping for adult flight of the first seasonal population will begin around petal fall. Monitoring for this generation will occur later in the season, late June to early July.

Plum Curculio damage has been observed on developing fruitlets in the Hudson Valley. Fruitlets become susceptible once they reach approximately 4-5mm in diameter. Adults typically become active after a few nights with temperatures of 55-60 degrees F, and move into orchards from hedgerows. Management typically begins at petal fall. Coverage should be maintained up to 308 DD Base 50 after petal fall. Use the NEWA PC Model to determine when you’ve reached the 308 DD Threshold.

Black Stem Borer has become very active in the Hudson Valley. Activity has been observed for the past few weeks in EtOH soaked bolts. Pay particular attention to trees with stress, including drought, too much water in the soil, winter damage. Look for frass in the lower part so the trunk, with small round entry holes.

Apple leafcurling midge first trap captures were recorded this week across NY State. This is an insect that sporadically causes damage in New York. Over the past few years we have received increasing reports of damage, particularly in isolated locations in Western NY and the Champlain Valley. Emergence is typically near TC, then rapid increase 3-4 generations per year in NY. Damage is evident a bit later, as tightly curled terminal leaves, curling inward rather than outward like leafhopper damage, and very brittle to the touch.

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.

Pest/Phenology Event	DD Base 43˚F		DD Base 50˚F		Approx. Date
	mean	std dev	mean	std dev	mean	std dev
Pink (McIntosh)	289	26	139	21	3-May	7 days
OFM Traps set out	Pink
Oriental fruit moth – 1^st adult catch	229*	44*	126	33	2-May	8 days
RBLR – 1^st flight peak	303	75	150	48	4-May	9 days
STLM – 1^st flight peak	337	71	168	45	7-May	8 days
Full bloom (McIntosh)	378	35	192	25	10-May	6 days
OBLR Overwintered Gen. Sample	Bloom
Codling Moth Traps set out	Bloom
Lesser appleworm – 1^st catch	420	144	217	88	13-May	12 days
American plum borer – 1^st catch	457	64	240	45	16-May	7 days
OFM – 1^st flight peak	369*	91*	223	57	15-May	11 days
Codling moth – 1^st adult catch	475	85	249	55	18-May	7 days
San Jose scale – 1^st adult catch	533	88	284	61	21-May	8 days
Cherry fruit fly traps set out	20-May
STLM – 1^st sap-feeding mines observed	472	129	241	76	18-May	13 days
Petal fall (McIntosh)	479	42	252	32	18-May	6 days