Codling Moth Larval Emergence Beginning In Highland. June 1st, 2020

1st gen. CM larva.

Codling moth (CM) has been flying at the HVRL since 15th May (Biofix for NEWA). Biofixes for codling moth along South Ohioville in New Paltz on 24th May and in Clintondale and Milton on 25th May.

Emergence of CM larva along the eastern Illinois mountain range in Highland & Marlboro predicted by the NEWA site for the 30th May, roughly 8-10 days later in cooler sites (New Paltz & Clintondale) with later biofix dates.

Apply the first spray for control of overwintering CM at 250 DD after first catch (June 1st in Marlboro & Highland sites earlier CM emergence, closer to the river). Plum curculio will still be active at this time and a broad spectrum material should be selected to control both of these pests at this time in high risk PC orchards. If internal worm damage has been observed in past years in an orchard, CM populations may be resistant to organophosphate and synthetic pyrethroid insecticides and other classes of materials may be more effective.

In orchard sites where CM injury to fruit has been observed, the use of newer lepidopteran insecticides should be employed to control the 1st generation. Materials containing Chlorantraniliprole (Altacor, Voliam Flexi WDG) or Cyantraniliprole (Exirel, Minecto Pro, Besiege) and Cyclaniliprole (Verdepryn 100SL) have excellent activity against CM. Both Cyantraniliprole and Cyclaniliprole have strong activity against plum curculio at highest labeled rates.

The Mirid bugs including Tarnished plant bug (TPB) feeding has been observed in early set fruit with TPB present in fruit clusters during observations made last Friday.

Generally, low European red mite have been observed to date due to cool temperatures and heavy rains experienced during the pre-bloom through petal fall period. That said, there are Hudson Valley orchards experiencing bronzing from ERM over the past two weeks now that weather is in a warming trend.

Lepidopteran ‘worm’ & leafroller: Significant feeding of developing terminal shoots has occurred in untreated apple over the past week with feeding on fruitlets in untreated trees. Increased feeding is likely to occur as we move past the thinning window with moderating temperatures. Curled foliage containing live lepidopteran larva is present in many commercial orchards that have not used materials targeting the larva. Materials to manage CM (Altacor, Spintor (Entrust), Spinetoram (Delegate), Chlorantraniliprole (Altacor, Voliam Flexi WDG) or Cyantraniliprole (Exirel, Minecto Pro, Besiege) and Cyclaniliprole (Verdepryn 100SL) will also control leafroller activity.

Rosy apple aphid (RAA) are also present in high numbers this season, causing leaf curl and misshapen dwarfed fruit. Insecticides used to control Plum Curcuilo, specifically thiomethoxam (Actara), a neonicotinoid, will reduce RAA. The addition of imidacloprid (Admire) or acidamdiprid (Assail) can also

Plum Curculio adult, scar and egg.

In-Depth: Plum Curculio (PC): Cool temperatures have kept the lid on migrating populations of PC over the past two weeks, delaying and or reducing oviposition in stone fruit in many locations in the Hudson Valley. However, as temperatures have climbed into the 80’s after petal fall and fruit size increasing across apple varieties, we observed the first sting from PC on fruit on May 25th with 18% injury to untreated apple along orchard borders (See Scouting Report for all insects).

We are looking at >18% PC injury in our untreated Ginger Gold in a heavily infested corner of our research orchard, in plots along an abandoned orchard to the north, a hedge row and woodlands to our east and south. In year in which warmer temperatures are present during bloom we would be looking at 50% injury by this point in time. PC activity is highly dependent upon temperature.

PC Model: We are presently at 196DD towards the 308DD representing complete migration of PC into orchards and insecticide residue no longer needed for PC. NOAA weather is predicting complete PC migration to occur on the 7th of June.

The model used to calculate the end of PC emergence begins at 95% petal fall of McIntosh. The majority of eggs deposited into fruit by overwintering plum curculio in the Northeast is completed in apples once 308 DD base 50 has been reached. (developed in studies conducted by by W. H. Reissig, J.P. Nyrop, and R. Straub (Environmental Entomology; 1053-1060; 1998; titled “Oviposition Model for Timing Insecticide Applications Against Plum Curculio (Coleoptera:Curculionidae) in New York State”).

In choosing insecticides for PC management, considerations should be made based on the mode of action of the active ingredient. John Wise, Michigan Stat Fruit Entomologist, discusses the Lethal, Antifeedant and Curative activities of insecticides that may be helpful in your decision making in tree fruit PC management. It can be found in the article titles ‘Effectively controlling plum curculio in stone and pome fruits‘.

Plum Curculio: CALS Guidelines 2020

We recommend maintaining residual protection from the high rate of an effective insecticide for PC. Take note that residual activity is no longer effective when 2 inches of cumulative rain occurs within the first 10 days after application, 1.5 inches of cumulative rain occurring from 10-14 days after application, or 14 days has passed since the previous application with no rain event. Rains later this week may reduce residual with 0.2 inches predicted for Wednesday / Thursday.

Application modeling for CM Trap Captures 2019

Codling moth: The Tortricid complex of Red Banded Leaf Roller (RBLR), Oriental Fruit Moth (OFM), and Codling Moth are now in flight with the Obliquebanded Leafroller (OBLR) still in the larval stage moving toward pupation. The most important of the internal lepidopteran being codling moth, has taken flight with the first adult male found in pheromone traps last week, on May 15th in Highland. The degree day CM model has accumulated 122DD toward the 220 accumulated degree days (base 50°F) to forecast larval emergence. We are predicting 1st CM larva emergence within the next 5 days or May 30th this season.

Over the past 18 months, the loss of sound fruit at pack out from codling moth appears to be fairly universal in the northeast. Over the past few years we have seen a rise in CM numbers in traps and in orchard infestations. In 2016, a third generation emergence in September gave rise to relatively high losses, providing a foothold of CM to establish in many regional orchards.

Conventional material options are listed in the Cornell Guidelines.

CALS Guidelines for Adult Codling Moth at PF

An additional option is to apply a granulosis virus formulation at 200-250 DD 50°F. High moth pressure requires 2-3 sprays for the first generation, but in lower pressure orchards (with counts of less than 5 moths per trap per week), you can control CM with a single spray timed at 350 DD 50°F.Codling moth granulosis virus. Formulations include Cyd-X, Cyd-X HP, Madex HP by Certis. Fruit monitoring for CM infestation is essential using granulosis virus.

Codling Moth Granulosis Virus contains an insecticidal baculovirus, Cydia pomonella granulovirus, which is specific to the larval form of the codling moth, and is registered for use in apples, pears, and (Cyd-X only) plums. This biological insecticide must be ingested in order to be effective, after which the viral occlusion bodies dissolve in the larval midgut and release infectious virions. These enter the cells lining the digestive tract, where they replicate; eventually, the other tissues are infected and the larva stops feeding and eventually (within 3-7 days) dies. After death, the larva disintegrates, releasing billions of new occlusion bodies, which may infect other codling moth larvae upon ingestion. No adverse effect to fish, wildlife or beneficial organisms has been observed; it has a low bee-poisoning hazard.

Insecticide Resistance Development in Codling Moth:

The organophosphate class of insecticides, including Guthion (azinphos-methyl) and Imidan (phosmet) have been used since the 1960’s, for over 50 years, to manage the codling moth. The development of resistance by codling moth to Imidan is likely if its reoccurring use has been for Plum Curculio and or OBLR management during mid-summer. Consistent use during the past ten years or more increasing resistance potential. Those specific timings would provide some level of control of CM while providing various rates of residual exposure. Low rates of residual increase the selection for resistance during the early and mid-summer generations of the pest. A scenario, such as the switch from Guthion to Imidan in season long program use would affect the same target site (nerve receptor sites for ACh, acetylcholinesterase) within the insect to contribute to resistance.

In the Hudson Valley to date I don’t believe resistant strains are widespread, even though we are hearing of increasing reports of CM damage to tree fruit. The broad availability and use of insecticides that include the different IRAC classes of active ingredients for plum curculio from PF to 2nd cover and mid-summer management of OBLR, would reduce region-wide resistance of CM to any one specific insecticide class. We have seen the use of these materials to include Avaunt, Exirel, Calypso, Carbaryl, pre-mixes including pyrethroids or pyrethroids alone. Insecticides of various classes for the overwintering OBLR used at PF would likely impact CM to a lesser degree when used at petal fall timing.

There haven’t been recent studies to detect phosmet resistance to CM in NY that I’m aware of. In Michigan, a study in 2008 detected a 7-8 fold level of resistance in orchard site specific CM populations to codling moth (see abstract from work done by John Wise in Mich. State below). However, no resistance to acetamiprid (Assail) and spinosad (Delegate, Spintor, Entrust) was detected in the study.

That said, it’s very likely we have codling moth populations resistant to older insecticide classes, including pyrethroids and OP’s in orchards throughout the Northeast.

Insecticide rotation: I would suggest the use of specific materials for CM be employed during 1st-2nd cover and again in mid-July, when model predictions for larva emergence are called for AND in orchards with reoccurring fruit injury from CM. The use of Assail to manage apple maggot during 2nd generation CM larval emergence has been a good option, as it’s been shown to be one of the better materials against both CM & AM. The use of Delegate, Altacor at 1st – 2nd cover would reduce the resistance potential while picking up a few lingering overwintering OBLR. Mating disruption and granulosis virus are also good choices in conventional and organic production systems.

Remember to rotate classes for EACH GENERATION and not each spray during a generation, to reduce the potential for insecticide resistance.

Pest Manag Sci. 2008 Sep;64(9):881-90. doi: 10.1002/ps.1576. Resistance of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), larvae in Michigan to insecticides with different modes of action and the impact on field residual activity.

Mota-Sanchez D1, Wise JC, Poppen RV, Gut LJ, Hollingworth RM.

The codling moth is one of the principal pests of apple in the world. Resistance monitoring is crucial to the effective management of resistance in codling moth. Three populations of codling moth in neonate larvae were evaluated for resistance to seven insecticides via diet bioassays, and compared with a susceptible population. In addition, apple plots were treated with labeled field rate doses of four insecticides. Treated fruit were exposed to neonate larvae of two populations from commercial orchards.

RESULTS: Two populations of codling moth expressed two- and five fold resistance to azinphos-methyl, seven- and eight fold resistance to phosmet, six- and tenfold resistance to lambda-cyhalothrin, 14- and 16-fold resistance to methoxyfenozide and sixfold resistance to indoxacarb, but no resistance to acetamiprid and spinosad. The impact of the resistance to azinphos-methyl, measured as fruit damage, increased as the insecticide residues aged in the field. In contrast, fruit damage in methoxyfenozide- and lambda-cyhalothrin-treated fruit was observed earlier for resistant codling moth. No differences in efficacy were found for acetamiprid.CONCLUSIONS: Broad-spectrum insecticide resistance was detected for codling moth. Resistance to azinphos-methyl, lambda-cyhalothrin and methoxyfenozide was associated with reduced residual activity in the field. Broad-spectrum resistance presents serious problems for management of the codling moth in Michigan.