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WNC Orchard Insect Populations

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Insect trap in apple orchardMay 24, 2022

Codling moth remains the key insect of concern at this time. Egg hatch degree-day (DD) model accumulations range from about 440 DD in Henderson County to 600 in Cleveland County. While first-generation codling moth can potentially be a concern up until 800 to 1000 DD, depending on population density, the most critical period for protection is typically between about 300 to 800 DD. Rain, cool nights and moderate daytime temperatures over the next 4 to 5 days will likely suppress moth activity.

Tufted Apple Bud Moth (TABM): In lower elevation orchards (<1000 ft) we are approaching the wide window of opportunity for tufted apple bud moth control. Control of this leafroller is easily achieved with one application of a recommended insecticide anytime between 800 and 1200 DD after biofix. DD accumulations range from about 590 in Henderson County to 800 in Cleveland County. In lower elevation orchards control of this generation can be achieved with an application anytime between now and the first week of June. In Henderson County, where TABM populations are generally the highest in this region, the window for control is expected to be during the first two weeks of June. For those monitoring TABM activity, it is important to remember that egg laying does not begin until pheromone trap captures peak, so do not be concerned about high trap captures at this time.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2022 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
May 9 May 16 May 23
Codling moth  4.0 2.0 1.0
Oriental fruit moth 9.0 3.0 4.5
Tufted apple bud moth 16.0 18.0 42.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 0.0 6.0
Lesser appleworm 10.0 5.0
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial)
Brown marmorated stink bug (unsprayed) 0.0 0.0 1.0
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer 7.0 38.0 80.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 33.0 18.0 28.0
San Jose scale 0.0 0.0 0.0
Ambrosia beetle (all species) 1.3 2.0 6.3

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2022 Accumulated Degree Days

HENDERSON COUNTY
May 9 May 16 May 23
Codling moth (Biofix: April 22) 200 296 429
Oriental fruit moth (Biofix: April 12) 390 519 686
Tufted apple bud moth (Biofix: April 27) 193 321 488

About degree-day models


2022 Pest Trends (click to enlarge)

Chart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trends


PREVIOUS UPDATES

May 17, 2022

Codling Moth, European Red Mite

Codling moth remains the key pest that poses a threat to apples. This is also a time to consider a preventive miticide application for those using this approach in specific orchards or cultivars.

Mountain Horticultural Crops Research Station apple orchardCodling Moth

Egg hatch degree-day models range from about 300 DD in Henderson County to about 440 DD in lower-elevation Cleveland County. In Henderson County, this week is optimum timing for an initial insecticide in orchards with historically low population densities. In orchards with moderate to high populations of codling moth, last week was optimum timing for the first insecticide application. In orchards using mating disruption, it is doubtful that an insecticide is necessary unless pheromone traps are consistently capturing moths.

In orchards at lower elevations where DD accumulations are greater than 400, applications at this time should be based on intensity of moth captures in pheromone traps. If there is no trapping being conducted, it would be wise to assume populations are high and to make a total of 3 applications at 2-week intervals during the first generation. In lower-elevation orchards using mating disruption for codling moth, it is recommended that a single insecticide be applied against the first generation codling moth. This application should coincide with tufted apple bud moth DD accumulations reaching about 800, which is expected to occur next early next week.

Preventive Control of European Red Mite

In orchards with a history or European red mite problems, several options are available for preventive control that usually provides season-long suppression. These include Apollo, Savey, Zeal, Envidor and Agri-Mek. For resistance management purposes, rotate products with different modes of action annually. Apollo and Savey are the same mode of action (MOA group 10A), so do not use either of these in successive years. Agri-Mek should be applied at petal fall to first cover, and either a horticultural oil or penetrating adjuvant should be used to maximize uptake by leaves – if using oil do not use within 14 days of using Captan.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2022 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
May 2 May 9 May 16
Codling moth  12.0 4.0 2.0
Oriental fruit moth 12.0 9.0 3.0
Tufted apple bud moth 7.0 16.0 18.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 0.0 0.0
Lesser appleworm 0.0
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial)
Brown marmorated stink bug (unsprayed) 1.0 0.0 0.0
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer 0.0 7.0 38.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 45.0 33.0 18.0
San Jose scale 0.0 0.0 0.0
Ambrosia beetle (all species) 2.3 1.3 2.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2022 Accumulated Degree Days

HENDERSON COUNTY
May 2 May 9 May 16
Codling moth (Biofix: April 22) 104 200 296
Oriental fruit moth (Biofix: April 12) 260 390 519
Tufted apple bud moth (Biofix: April 27) 62 193 321

About degree-day models


May 10, 2022

Apple fruitCodling Moth and San Jose Scale

With petal fall sprays complete, the insects of interest during the next few weeks are first generation codling moth and San Jose scale. San Jose scale management options were discussed in last week’s update.

Codling Moth

The codling moth degree-day (DD) model is an excellent tool for timing insecticide applications, while pheromone trap captures can help determine the frequency of applications over the next three to four weeks. Under moderate to high populations, which are usually associated with some damage the previous year and pheromone trap captures greater than 5 to 10 per week, an initial insecticide application should be made about 250 DD after biofix. Under low population densities, initial application can be delayed until about 350 DD. Biofix in Cleveland County (1000 ft elevation) and Henderson County (2000 ft elevation) occurred on 15 and 22 April, respectively. Wilkes County is generally between these dates, depending on elevation of the orchard. As of 9 May, cumulative DD were 340 DD in Cleveland Co. and 210 in Henderson Co. NOTE: In orchards using mating disruption for codling moth, a single insecticide application at approximately 600 DD is recommended, which will coincide with timing for tufted apple bud moth.

To help avoid the development of insecticide resistance, it is important to use different modes of action against first and second generation (which occurs in July) codling moth. For instance, if a MOA group 28 insecticide is used (e.g., Altacor, Exirel, or Verdepryn) against the first generation, regardless of how many times it is applied, do not use any of these insecticides against the second generation in July. Alternatively, if Delegate (MOA group 5) is used for first generation control, do not use this product in July. While these two groups have the highest efficacy ratings against codling moth, other insecticides that will provide good control under low to moderate populations include Assail, Intrepid, Imidan, and Rimon. The rotation stipulation also holds for use of these insecticides, so if one of these products is used during the first generation, it should not be used in July, and vice versa.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2022 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Apr 25 May 2 May 9
Codling moth  8.0 12.0 4.0
Oriental fruit moth 10.0 12.0 9.0
Tufted apple bud moth 0.0 7.0 16.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 0.0 0.0
Lesser appleworm
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial)
Brown marmorated stink bug (unsprayed) 0.5 1.0 0.0
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer 0.0 0.0 7.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 24.0 45.0 33.0
San Jose scale 0.0 0.0 0.0
Ambrosia beetle (all species) 2.0 2.3 1.3

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2022 Accumulated Degree Days

HENDERSON COUNTY
Apr 25 May 2 May 9
Codling moth (Biofix: April 22) 41 104 200
Oriental fruit moth (Biofix: April 12) 172 260 390
Tufted apple bud moth (Biofix: April 27) 62 193

About degree-day models


May 3, 2022

Person checking ambrosia beetle trapPetal Fall to First Cover Sprays

Depending on location, some are still applying petal fall sprays and others are approaching first cover. Last week’s update focused on petal fall and the importance of choosing an insecticide effective against plum curculio and oriental fruit moth. However, there have been some questions about the efficacy of insecticides recommended at petal fall against green fruitworm, which was not included in the relative efficacy table because of its sporadic occurrence. Nonetheless, any insecticide with a rating of 4 or more against oriental fruit moth is also highly effective against green fruitworm, including Assail, Imidan, Verdepryn and Voliam Flexi.

As we approach the first cover spray, attention will turn to the codling moth and San Jose scale.

Codling moth

Biofix for the codling moth degree-day model was set as 22 April at the Mountain Horticultural Crops Research Station in Mills River (elevation 2,067 ft). Biofix in lower elevation orchards such as Cleveland County generally occurs about one week earlier. As of today (3 May), about 120 DD have accumulated in Henderson County. In Cleveland County, assuming a biofix date of 15 April, approximately 220 DD have accumulated.

In orchards with moderate to high codling moth populations, an initial insecticide application should be made at 250 DD, which will occur later this week in lower elevation orchards (about 1000 ft). At higher elevations, such as Henderson County (about 2,000 ft), 250 DD is predicted to occur in 8 to 10 days. However, in orchards with low codling moth populations, initial insecticide applications can wait until about 350 DD. Finally, insecticides targeting first generation codling moth are generally not needed in orchards using mating disruption for codling moth, but monitoring with pheromone traps can help determine if a supplemental application is needed.

Next week’s update will focus on codling moth insecticide options and resistance management strategies.

San Jose Scale (SJS)

With prebloom Lorsban (chlorpyifos) no longer an option for San Jose scale, greater focus is now placed on timing applications for emergence of first generation crawlers, which occurs near the first cover spray (see figure below).

Two commonly used and excellent materials for SJS are Esteem and Centaur, and for resistance management they should be rotated annually. It should also be noted that under low codling moth pressure Esteem will also serve as an effective codling moth control, primarily due to its ovicidal activity. Other insecticides that will provide good control of SJS at first cover include Diazinon 50W, Assail, and Movento.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2022 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Apr 20 Apr 25 May 2
Codling moth  0.0 8.0 12.0
Oriental fruit moth 21.0 10.0 12.0
Tufted apple bud moth 0.0 0.0 7.0
Redbanded leafroller 3.0 0.0 0.0
Obliquebanded leafroller 0.0 0.0 0.0
Lesser appleworm
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial)
Brown marmorated stink bug (unsprayed) 0.0 0.5 1.0
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer 0.0 0.0 0.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 6.0 24.0 45.0
San Jose scale 0.0 0.0 0.0
Ambrosia beetle (all species) 11.0 3.5 1.5

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2022 Accumulated Degree Days

HENDERSON COUNTY
Apr 20 Apr 25 May 2
Codling moth (Biofix: April 22) 41 104
Oriental fruit moth (Biofix: April 12) 87 172 260
Tufted apple bud moth (Biofix: April 27) 62

About degree-day models


Bee on apple flowerApril 26, 2022

Petal Fall Spray Options

Insects to be targeted with insecticide sprays at petal fall include Plum Curculio, and possibly Oriental Fruit Moth (OFM), and Rosy Apple Aphid. The need for control of the latter two is dependent on what, if any, insecticide was applied before bloom. Prebloom insecticide sprays typically target rosy apple aphid and San Jose scale, but since they can both be controlled at petal fall or first cover with the proper selection of insecticide(s), prebloom insecticide sprays usually are not necessary. (Note: oil at green tip is always recommended to suppress European red mite and San Jose scale populations and reduce risk of infestations later in the season). Finally, if mating disruption is being used for OFM and codling moth, OFM control with insecticides is not necessary.

Plum Curculio: This remains one of the most common causes of insect damage to apples in this region, and effective control is highly correlated with petal fall sprays. Although the severity of damage varies considerably among orchards, plum curculio is ubiquitous and can cause damage in virtually every orchard. In orchards with a history of problems, sprays should be made as quickly after petal fall as possible. In orchards where damage is historically low, there is usually a longer buffer period and sprays can be slightly delayed. However, 1st Cover is often too long to wait.

Rosy Apple Aphid:  Rosy apple aphid is a sporadic pest, but it can be difficult to monitor and control with curative applications of insecticides. Most neonicotinoids and closely related insecticides are effective against RAA, and effective control can be achieved before bloom at Pink, or after bloom at petal fall.

Oriental Fruit Moth:  Biofix at the research station in Henderson County was set on 12 April, and off the mountain in Cleveland County it typically occurs about one week earlier. In orchards using mating disruption for OFM, insecticidal control of the first generation is not necessary, so focus on plum curculio and rosy apple aphid if relevant. However, where mating disruption is not used, an insecticide effective against this pest is recommended to control the first generation.

Insecticide Options:  Because of the importance of plum curculio, only those insecticides with activity against this pest are recommended at petal fall. Below is a table of depicting the relative efficacy of various insecticides targeting pests at petal fall. San Jose scale and preventive control of European red mite are not included here, because 1st Cover is generally a more effective timing. Also, insecticides that may aggravate San Jose scale or European red mite populations (mostly pyrethroids) are not recommended at petal fall.

Relative Efficacy of Insecticides for Petal Fall

(─ no activity, 1 = least effective, 5 = most effective)
Insecticide (active ingredient) Plum Curculio Rosy Apple Aphid Oriental Fruit Moth European Red Mite
Actara (thiamethoxam) 5 5 2
Assail (acetamiprid) 3 5 4
Belay (chlothianidin) 4 5 3
Avaunt (Indoxacarb) 4 4
Imidan (phosmet) 5 4
Verdepryn (cyclaniliprole) 4 5
Agri-Flex (abamectin + thiamethoxam) 5 5 2 5
Voliam Flexi (thiamethoxam + chlorantraniliprole) 5 5 5

Learn more about southeastern apple insect pests at the Apple Insect Management page.


2022 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Apr 12 Apr 20 Apr 25
Codling moth  0.0 0.0 8.0
Oriental fruit moth 12.0 21.0 10.0
Tufted apple bud moth 0.0 0.0 0.0
Redbanded leafroller 2.0 3.0 0.0
Obliquebanded leafroller 0.0 0.0 0.0
Lesser appleworm
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial)
Brown marmorated stink bug (unsprayed) 0.0 0.0 0.5
Spotted tentiform leafminer 2.0 0.0 0.0
Dogwood borer 0.0 0.0 0.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 1.0 6.0 24.0
San Jose scale 0.0 0.0 0.0
Ambrosia beetle (all species) 2.0 11.0 3.5

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2022 Accumulated Degree Days

HENDERSON COUNTY
Apr 12 Apr 20 Apr 25
Codling moth (Biofix: April 22) 41
Oriental fruit moth (Biofix: April 12) 0 87 172
Tufted apple bud moth (Biofix TBD)

About degree-day models


Apple flowersApril 5, 2022


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2022 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Mar 21 Mar 28 Apr 4
Codling moth  setup
Oriental fruit moth 0.0 2.0 0.0
Tufted apple bud moth setup
Redbanded leafroller 8.0 1.0 2.0
Obliquebanded leafroller setup
Lesser appleworm
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial)
Brown marmorated stink bug (unsprayed) setup
Spotted tentiform leafminer setup
Dogwood borer setup
Peachtree borer setup
Lesser peachtree borer setup
San Jose scale setup
Ambrosia beetle (all species) 0.0 1.5 0.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2022 Accumulated Degree Days

HENDERSON COUNTY
Codling moth (Biofix TBD) n/a
Oriental fruit moth (Biofix TBD) n/a
Tufted apple bud moth (Biofix TBD) n/a

About degree-day models