April 28, 2025

With petal fall sprays completed throughout the region, the focus for the next few weeks will be on first generation codling moth. The codling moth degree-day model predicts egg hatch from 250 DD to about 1,000 DD. Currently, degree-day accumulations in lower elevation locations (e.g., Cleveland County) are predicted to reach 250 DD this Wednesday (April 30), while in Henderson County 250 is not predicted until May 7.

The number of insecticide applications and choice of materials to apply will depend on: 1) whether or not mating disruption is being used, 2) the intensity of codling moth populations in individual orchards, and 3) weather conditions. The best decisions are made when pheromone traps are being used to monitor the intensity of populations, and use of the codling moth degree-day model to time applications with egg hatch of the first generation.

Mating Disruption: In orchards where mating disruption has been used for 3 or more years, codling moth populations are typically so low that insecticides are usually not needed. However, pheromone trapping is still recommended to confirm the absence of moth activity and/or detect the “unexpected.”  We recommend a threshold of at least 3 cumulative moths captured over a 2-week period to dictate supplemental insecticide sprays under mating disruption (see below for lure types).

Non-Disruption Orchards: Where mating disruption is not being used for codling moth, pheromone trapping is especially important to monitor the intensity of moth populations and help determine frequency of insecticide use during the first generation. While there is not a well established relationship between moth populations and damage, a conservative threshold level of 5 moths over a one week period (using a CM L2 lure) has been successful in minimizing damage.

Pheromone Traps: The type of trap and pheromone lure used is important for codling moth monitoring programs. Either wing traps or Delta traps are recommended. Delta traps are easier to use since they have sticky cards (liners) that easily slide into and out of the trap. Plus the Delta trap provides better protection against rain. Placing traps in the upper one-third of the canopy is recommended, because moth activity is concentrated in this area. Finally, there are several types of pheromone lures available for purchase, but our recommendations have all been developed using the Trece CM L2 lure, which has a 2X rate of pheromone and should be replaced at 8-week intervals. A longer lasting lure (CM L2-P) that needs to be replaced at 12-week intervals has recently been developed and performs similarly to the CM L2.

The number of traps to deploy needs to be a compromise between detection of moths when populations are low and what is practical. One trap per 10 acres of orchard is considered the minimum, but location is probably more important. Traps should be placed at locations where moth numbers are suspected of being high, such as near packing houses, bin storage areas, or adjacent to nearby abandoned orchards.

Codling Moth Degree-Day Model: A codling moth degree-day (DD) model that predicts egg hatch of each generation was developed in the 1970s in Michigan, and has been a key tool used to time insecticide applications. The original model has been refined and updated with phenology data to different regions, including western NC. First generation egg hatch is predicted to occur from about 250 DD through 1,000 DD. However, the length of egg hatch varies considerably depending on the size of the population. Models were developed using high population densities, and only under this scenario does egg laying occur over the entire period from 250 to 1000 DD; hence, the importance of using traps to monitor the intensity of populations.

Insecticide Options: Since 2008, the apple industry has relied primarily on two groups of insecticides for codling moth control – the diamides (Altacor, Exirel, and Verdepryn) and spinosyns (Delegate). While some resistance has been detected in more northern apple areas, to date none has been suspected in the southeast. Relying on only one mode of action (diamides versus spinosyns) during a respective generation has been a good resistance management strategy. It should be noted that under low to moderate codling moth populations, initial egg hatch can occur later than 250, so using an alternative insecticide at 250 DD can help to further minimize use of the diamides and spinosyns. Among the alternatives, Assail and Imidan are the most effective alternatives. An advantage of Assail is that it also has San Jose scale activity.

Relative Efficacy of Insecticides for Codling Moth

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

2025 Average Weekly Trap Captures

April 21, 2025

The majority of apples throughout the region are at petal fall, with some later cultivars still blooming. As discussed in last week’s update, plum curculio and oriental fruit moth are the key pests of concern (see table of insecticide options below). Also, for those that did not apply an insecticide targeting San Jose scale before bloom, a product effective against that insect should be made by First Cover.

At the Mountain Horticultural Crops Research Station in Mills River, codling moth biofix occurred today (April 21). While we do not have traps off the mountain, biofix in Cleveland and Lincoln County is usually about 7 days before Henderson County, so for modeling purposes we have set biofix in those areas as April 14. Based on the weather forecast, It is anticipated that an initial insecticide application targeting codling moth (about 250 DD, early egg hatch) in the Cleveland/Lincoln County area will occur on April 29 or 30. In Henderson County, it will likely be another 2 weeks before codling moth egg hatch begins.

Relative Efficacy of Insecticides for Petal Fall

(─ no activity, 1 = least effective, 5 = most effective)

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

2025 Average Weekly Trap Captures

April 14, 2025

Petal fall is a critical time for management of plum curculio, and potentially oriental fruit moth and rosy apple aphid, the latter two dependent on what insecticides or mating disruption products were used before bloom. Also, if an insecticide targeting San Jose scale was not applied before bloom, petal fall to first cover falls in the timeframe for targeting this pest.

It is also important to note that most orchards consist of multiple apple cultivars that have differing times for petal fall, and precautions should be taken to avoid exposing bees to insecticide sprays or residues in flowers.

Petal Fall Sprays and Bee Safety

Minimizing risk of insecticide exposure to bees involves common sense and following restrictions on labels. The following guidelines should be used:

• Insecticides should not be applied before >90% of petals have fallen from blooms. Anytime before this stage risks exposing bees to insecticides. This is especially true when applying insecticides highly toxic to bees (see table below).
• Insecticides toxic to bees should not be applied before hives are removed from an orchard, regardless of the presence or absence of flowers.
• In orchards with multiple cultivars, avoid spraying insecticides until petal fall is complete on all cultivars. Attempting to spray trees that have completed petal fall but which are adjacent to those with blooms still present, will likely expose bees on blooming trees due to spray drift directly or indirectly (i.e., spray drift to flowers can contaminate nectar and pollen).

Insecticide Options for Petal Fall

Insecticide recommendations at petal fall are shown in the table below. Unfortunately, most are highly toxic to bees, especially those recommended for plum curculio – the key target at this time. Hence, the importance of waiting until >90% petal fall to make applications.

Plum curculio (PC): The key pest at this time, and the one which should be a strong basis for insecticide selection.

Oriental fruit moth (OFM): Another common pest, and the first generation can be easily managed with an insecticide applied at petal fall. However, in orchards using mating disruption and where dispensers were in place by before pink, insecticides are probably not necessary.

Rosy apple aphid (RAA): Rosy apple aphid control at petal fall is only necessary if an insecticide effective against this pest was not applied before bloom, at the tight cluster to pink stage.

San Jose scale (SJS): If an insecticide targeting San Jose scale was not applied before bloom, the window for making a post bloom spray extends from petal fall to first cover.

Preventive control of Mites: For those that prefer preventive control of European red mites, petal fall is the optimum timing if using Agri-Mek. The efficacy will noticeably decline the further from petal fall it is applied. If using insect growth regulators (e.g., Apollo, Savey, Zeal) or Envidor, it is recommended to wait until first or second cover.

Relative Efficacy of Insecticides for Petal Fall

(─ no activity, 1 = least effective, 5 = most effective)

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

2025 Average Weekly Trap Captures

April 7, 2025

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

2025 Average Weekly Trap Captures

With trees either in or approaching bloom, hopefully orchards have received an oil application at green tip for early season suppression of San Jose scale (SJS) and European red mite (ERM). Additionally, an insecticide application between tight cluster to pink is an option for additional protection against SJS, and for preventive control of rosy apple aphid. If these latter applications were not made, post bloom options remain for control these two insects.

San Jose Scale: In addition to Esteem and Centaur, which are the two most effective materials and can be applied either before or after bloom, the organophosphates Diazinon and chlorpyrifos (2025 is the last year for use) are registered for use before bloom. However, these two older materials are generally not as effective. The neonicotinoid Assail also has good activity against SJS, especially when applied after bloom.

Rosy Apple Aphid: Historically, rosy apple aphid (RAA) control has been achieved with an effective material applied either before bloom at pink, or post bloom at petal fall. However, in recent years the petal fall timing, in the absence of a prebloom spray, has not been as effective. RAA overwinters in the egg stage, and eggs begin to hatch at petal fall when they are most vulnerable to insecticides. There are several options for the pink spray, including Assail, Sivanto Prime, Versys, and Beleaf, all of which will provide good control of RAA and are among the products less harmful to pollinators.

The next Pest Update will focus on management of insects at petal fall.

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

2025 Average Weekly Trap Captures