Codling moth management options for Michigan apples

Jackie Perkins<albertj9@msu.edu> and Julianna Wilson<jkwilson@msu.edu>, Michigan State University Department of Entomology - June 12, 2024

Updated from an original article written by John Wise and Larry Gut, Michigan State University Department of Entomology.

Optimize first generation codling moth management by using the degree-day model to time interventions and scouting to track thresholds.

An apple with frass and damage on it caused by codling moth. — Photo 1. Fruit damage and frass from codling moth larva. Photo by Jackie Perkins, MSU.

Codling moth biology

The codling moth is a key fruit-feeding pest of apples and pears. Codling moth begin to develop into pupae from overwintered larvae at around the pink bud stage of apples. Adults emerge beginning with apple bloom, with continuous emergence of adults for about six to seven weeks. On warm evenings when temperatures are above 60 degrees Fahrenheit, female moths will sit in the upper third of the tree canopy and call males by emitting a species-specific pheromone blend. Males find calling females, they mate, and then females lay their eggs on leaves near developing fruit. Eggs typically start to hatch one to two weeks after they are laid. We can expect two generations of codling moth each growing season in Michigan.

An apple cut in half with codling moth larva on the inside. — Photo 2. Codling moth larva inside an apple. Photo by Mark Longstroth.

Setting a biofix for the codling moth model

Male moths can be lured into traps baited with a synthetic pheromone blend. The first date of sustained captures of males in traps is used to set a biofix for the codling moth degree-day model, which uses accumulated degree-days for predicting key pest life stages and helps target the proper timing for management. You can access the codling moth degree-day model on Michigan State University Enviroweather.

Setting the biofix for codling moth requires setting up a trap with the right lure at the pink bud stage. The right lure depends on whether or not mating disruption products are being used to suppress codling moth. In orchard blocks that are not under mating disruption, the 1x lure can be used for both setting a biofix and monitoring for action thresholds (Table 1). In orchard blocks that are under mating disruption, use a trap with a 10x lure to set your biofix, but then use the 1x lure when monitoring for thresholds (Table 2).

If you didn’t set up traps in time to set a biofix specific to your farm, you should contact your local Michigan State University Extension fruit educator about regional biofixes that have been set. To get the most benefit from interventions against first generation codling moth, growers should treat a block after moth captures have been recorded and the accumulation of degree-days required for a particular action, as indicated in Table 1 for undisrupted blocks and Table 2 for disrupted blocks.

Table 1. Codling moth degree-day (DD) model and insecticide timings for controlling the first generation in blocks NOT using pheromone mating disruption. DD calculations use a 50 F base temperature.
Timing	Event	Action
Pink bud	Development of overwintering larvae	Use 1x lures, and set traps in upper third of canopy, near orchard edge or in areas with expected high pressure, one trap for every 2 acres. In large uniform blocks, one trap for every 5-10 acres is acceptable. In undisrupted blocks, 1x lures are used for both setting a biofix and monitoring for thresholds. Add lure change reminder to calendar.
Biofix	First sustained moth captures	Set DD = 0 Action threshold: an accumulation of 5-7 moths in any one trap; use biofix + DD to select product type based on timing.
		In blocks with HIGH pressure:	In blocks with LOW pressure:
100 DD from biofix	First generation egg laying (oviposition)	Treatment #1: timing for an ovicide material.
250 DD	Start of first generation egg hatch	Alternate treatment #1: timing for a larvicide material.
350 DD	First generation egg laying and hatch	Treatment #2: timing for a larvicide material if an ovicide was applied at 100 DD	Treatment #1: delayed timing of first application of larvicide materials
500-650 DD	Peak of first generation egg hatch	Timing for additional larvicide if threshold is exceeded. Reset cumulative count after treatment.
1000 DD	Expected end of first generation activity	Check fruit for damage (Photos 1 and 2); this will be an early indicator of second generation pressure.

Table 2. Codling moth degree-day (DD) model and insecticide timings for control of the first generation in blocks that ARE under pheromone mating disruption. DD calculations use a 50 F base temperature.
Timing	Event	Action
Pink bud	Development of overwintering larvae	Set up trap with a 10x lure to determine biofix in mating disrupted blocks. Use traps with 1x lures to monitor pressure and determine action thresholds. Set traps in upper third of canopy, near orchard edge or in areas with expected high pressure. For threshold monitoring use one trap for every 2 acres. In large uniform blocks, one trap for every 5-10 acres is acceptable. Add lure change reminder to calendar.
Biofix	First sustained moth captures	Set DD = 0 Action threshold (in disrupted blocks): 1 moth in a trap baited with a 1x lure; use biofix to select product type based on timing.
		In blocks with HIGH pressure:	In blocks with LOW pressure:
100 DD from biofix	First generation egg laying (oviposition)	Treatment #1: timing for ovicide materials.
250 DD	Start of first generation egg hatch	Alternate treatment #1: timing for larvicide materials.
350 DD	First generation egg laying & hatch	Treatment #2: if an ovicide was applied at 100 DD	Treatment #1: delayed timing of first application of larvicide materials
500-650 DD	Peak of first generation egg hatch	Timing for additional larvicide if threshold is exceeded.
1000 DD	Expected end of first generation activity	Check fruit for damage (Photos 1 and 2); this will be an early indicator of second generation pressure.

Targeting eggs

Rimon (novaluron) is an insect growth regular (IGR) that has strong ovicidal activity, thus codling moth egglaying is the optimal timing for this material (Tables 1-3). Rimon applied at codling moth biofix plus 100 DD also provides excellent control of obliquebanded leafroller, and suppression of plum curculio (sublethal effects on subsequent generation).

Targeting larvae

Most insecticides registered for use against codling moth are aimed at killing larvae, and thus are typically applied beginning at 250 DD post biofix (Table 3). To prevent pesticide resistance developing in codling moth populations on your farm, it is strongly recommended that insecticides from one chemical class (e.g., same mode of action) be used for the duration of first generation, and a different chemical class selected for use against second generation.

Delegate (spinetoram) is in the spinosyn class of insecticides (IRAC Group 5) and will provide excellent control of either first or second generation codling moth. It kills larvae as they hatch and begin feeding, thus should be applied at the larvicidal timings indicated in Tables 1 and 2. Delegate also has very good activity against obliquebanded leafroller, suppression activity on apple maggot, and limited lethal action on plum curculio when ingested (Table 4). Entrust (spinosad) is an OMRI approved spinosyn insecticide that will provide fair to good control of codling moth, but good control requires precise timing and excellent coverage since this material must be ingested by the larvae and may take days to cause mortality. Also, an adjuvant is strongly recommended when using Entrust.

Altacor (chlorantraniliprole), Exirel (cyantraniliprole) and Verdepryn (cyclaniliprole) belong to the diamide class of insecticides (IRAC Group 28). They will provide excellent control of either first or second generation codling moth, as well as obliquebanded leafroller and oriental fruit moth (Table 4). Exirel and Verdepryn also provide good to excellent control of green apple aphid and rosy apple aphid, as well as good control of plum curculio and apple maggot (Table 4).

The neonicotinoid (IRAC Group 4A) Assail (acetamiprid) will provide very good control of codling moth with a residual action of 10-14 days. This compound is primarily larvicidal, but also has some ovicidal activity when applied over the top of the egg. Assail is a fairly broad-spectrum material. The major secondary targets of neonicotinoids are the sucking insects, specifically aphids (green apple aphid and rosy apple aphid) and leafhoppers (Table 4). The initial application of Assail targeting first generation codling moth will also provide control of plum curculio, oriental fruit moth, San Jose scale crawlers and spotted tentiform leafminer. Belay (clothianidin), another neonicotinoid registered for use in pome fruits, is not as effective for second generation codling moth.

Beleaf (flonicamid) targets a different neural pathway (IRAC Group 29) and is also labeled for codling moth, but research trials have indicated that its best use is against the first generation only. Beleaf is a good material if you are also targeting early season aphids (green apple aphid and rosy apple aphid).

Proclaim (emamectin benzoate) is in the avermectin class of insecticides (IRAC Group 6). It has provided good control of first generation codling moth in trials at the Trevor Nichols Research Center and in on-farm demonstration trials. Proclaim also has very good activity against obliquebanded leafroller.

Spear-Lep (GS-omega/kappa-Hxtx-Hv1a) is a peptide-based biopesticide (IRAC Group 32) that must be tank mixed with a material containing Bt and ingested by early instar larvae. It provides good control of codling moth, cutworms and leafrollers and is best used against first generation codling moth.

Another biopesticide is the Granulosis virus (Cydia pomonella granulovirus (CpGv) e.g., Cyd-X, MadexHP, Carpovirus, ViroSoft). This biopesticide is specific to codling moth and provides fair to good control. The virus must be ingested by larvae and may take several days to cause mortality. Apply in sufficient water for thorough coverage of tree canopy. Repeat as necessary to maintain control. Do not tank mix with lime sulfur, copper or Bt products. All formulations are approved for organic use.

There are pre-mix insecticides labeled for codling moth control that combine two active ingredients, including Besiege (chlorantraniliprole plus lambda-cyhalothrin), Gladiator (zeta-cypermethrin plus abamectin) Leverage (imidacloprid plus cyfluthrin) and Voliam flexi (thiamethoxam plus chlorantraniliprole). When these are used for codling moth control, you must not use a product in the second generation that is in the same chemical class as either of the pre-mix active ingredients to prevent the development of insecticide resistance.

There are two classes of insecticides that are not recommended for codling moth management in Michigan. These are pyrethroids (IRAC Group 3A) and organophosphates (IRAC Group 1B). Although pyrethroid insecticides provide moderate control of codling moth, their broad-spectrum activity can result in mite outbreaks. Organophosphate (OP) insecticides are also not recommended for use against codling moth because resistance to OP compounds has been detected in Michigan orchards throughout the state. In addition, populations resistant to OP compounds may also be resistant to pyrethroids.

Table 3. Chemical class, activity and timing of insecticides labeled for use against codling moth; except for the pre-mixes listed at the end, materials are listed in order of their optimal spray timing and then alphabetically within those timings.
Compound trade name	Chemical class	Life-stage activity	Optimal spray timing for codling moth	Mite flaring potential
Rimon	IGR (chitin inhibitor)	eggs, larvae	Biofix + 100 DD Residue under eggs	Low
Altacor, Exirel, Verdepryn	Diamides	eggs, larvae	Biofix + 200-250 DD	Low
Assail, Belay	Neonicotinoids	larvae, eggs & adults (limited)	Biofix + 200-250 DD	Medium
Beleaf	Pyrmidine carboxyamide	larvae, eggs & adults (limited)	Biofix + 200-250 DD	Low
Proclaim	Avermectin	larvae	Biofix + 200-250 DD	Low
Asana, Warrior, Danitol*	Pyrethroids	eggs, larvae, adults	Biofix + 250 DD	High
Delegate, Entrust	Spinosyn	larvae	Biofix + 250 DD	Medium
Granulovirus, Spear-Lep	Biopesticide	eggs, larvae	Biofix + 250 DD	Low
Imidan*	Organophosphate	eggs, larvae, adults	Biofix + 250 DD	Low - Medium
Besiege*	Diamide + Pyrethroid	eggs, larvae	Biofix + 200-250 DD	High
Gladiator*	Pyrethroid + Avermectin	eggs, larvae, adults	Biofix + 200-250 DD	Medium
Leverage*	Pyrethroid + Neonic.	eggs, larvae, adults	Biofix + 200-250 DD	High
Voliam flexi	Diamide + Neonic.	eggs, larvae	Biofix + 200-250 DD	Low - Medium

*Not recommended for use against codling moth in Michigan due to resistance issues and/or mite flaring potential when used against first generation codling moth.

Table 4. Relative activity spectrum of compounds against spring and early summer apple pests
	Primary pests					Secondary pests
Insecticide	CM	OFM	OBLR	PC	AM	STLM	GAA	RAA	LH	SJS
Rimon	***	**	***	**		**
Altacor	***	***	***	*	*	**			*
Exirel	***	***	***	**	**	**	**	***	**
Verdepryn	***	***	***	**	**		***	***
Assail	***	***		***	***	***	***	***	***	**
Belay	**	**		***	**	***	***	***	***	**
Beleaf	**	*					***	***	**	**
Proclaim	**	**	***			***
Pyrethroids†	**	**	**	**	**	**	*	*	*	**
Delegate	***	***	***	*	**	**				*
Entrust	*	*	***	*	*	***
Spear-Lep	**		**
Imidan†	***	***	***	***	***

CM-codling moth, OFM-oriental fruit moth, OBLR-obliquebanded leafroller, PC-Plum curculio, STLM-spotted tentiform leafminer, GAA / RAA -green / rosy apple aphid, LH-white apple and potato leafhoppers, SJS-San Jose scale

* Some activity, ** Better activity, *** Best activity relative to other insecticides

† Rating for CM assumes that the orchard does not have resistant populations.

This article contains pesticide recommendations based on research and pesticide regulations relevant to Michigan. However, changes in pesticide regulations occur constantly. Some pesticides mentioned may no longer be available and some uses may no longer be legal. Contact your local county Michigan State University Extension office if you have questions about particular materials.

The information contained within this article does not supersede pesticide label directions, nor is it meant to be exhaustive in terms of available materials registered for use in pome fruit against codling moth. To protect yourself, others, and the environment, always read the label before applying any pesticide.

For more information regarding pest management in commercial orchards, refer to the current version of the Michigan State University Extension Michigan Fruit Management Guide, E-154.

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).