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Management for 2nd Gen. Codling Moth: Apple Maggot Trap Numbers on the Rise: July 28th, 2020

Brief: Second generation flight of codling moth Laspeyresia pomonella (L.) (CM) is subsiding as egg laying and larva hatch continues this week. The 2nd application for CM is required 10-14 days from the first application if CM management is warranted.

Orchards that have fruit injury from first generation CM this season, have high trap captures >5 adults/trap/week and or are adjacent to infested or newly abandoned orchards will require management beginning at early hatch for each generation FOLLOWED by a 2nd application 10-14d later for the late emerging larva. Timing, excellent coverage, use of most effective materials, employing effective rates and incorporating resistance management strategies are becoming more important to obtain effective codling moth control.

The 2nd gen. flight began on 13th July in the lower and mid-Hudson Valley with early larval emergence requiring management on the 19th July. For sites using July 19th as the application date for 2nd gen. CM, the ‘clean-up application’ for late emerging larva should go on this week as weather conditions permit.

2020 CM DD Model

Apple maggot, Rhagoletis pomonella flights are on the increase in regional traps with ideal conditions for emergence given recent rains. Management is critical for both of these pests this week as weather forecast conditions for applications become favorable.

CM Injury to GingerGold 6.24

Overview: We are now in the 2nd of 3 possible codling Moth generations this week in Hudson Valley commercial orchards with conditions warranting management .

Significant injury to Hudson Valley tree fruit has been observed over the past few seasons from 1st generation codling moth (CM) larva. In our untreated blocks we’ve observed 18% injury from 1st generation codling moth (CM) in Ginger Gold fruitlets this season.

The second generation of CM has started this week with the the first flight of CM adults occurring on the 12th of July as the biofix date for the HVRL. Larva have been emerging from newly laid eggs since the 22nd of July.

Many of the regions apple orchards now have resident (endemic) populations of codling moth residing in their orchards from infestations occurring over the past few seasons. Assessing fruit injury from the 1st generation of codling moth by scouting for frass at the calyx and stem end of fruit is critical for mid-late season pest management decision making.

Codling moth, similar to many other arthropods, have higher success rates under dry and hot environmental conditions. In the case of CM, high levels of larval survival can in some years be attributed to high endemic populations residing in the orchard, favorable weather conditions, reduced efficacy due to poor coverage or frequently used materials to which CM have become less susceptible, and often most ….can enter fruit due to delayed timing of insecticides well after 1st hatch of CM larva.

Conversely heavy rains can reduce CM egg laying while survival of 1st instar larvae of the codling moth have been found to be adversely affected by rainfall (Hagley (1972b)).

Rain events during the upcoming latter part of the week may produce heavy rain in pockets throughout the region depending on location, with clear skies forecast for the the next two days. Regarding CM larva, if intense rain events occur, it will likely have some adverse effect on larval populations yet will not be sufficient to manage the pest. That said, covering up for both codling moth and apple maggot is critical as application windows open beginning today into the following week with favorable wind conditions.
Focus on specific blocks where specific variety fruit injury was observed last season. Remove suspect fruit and slice through the center to look for seed feeding indicating codling moth larva presence. If codling moth injury is observed in fruit, management is required to reduce further injury during 2nd generation larval emergence.

In the mid-Hudson Valley, larval emergence will occur during the latter part of this week, requiring management in blocks with historical damage or adult trap capture exceeding >5 CM adults per week. Maintaining residue of effective insecticide on a 2 week schedule based on weather.

This insect continues to re-emerge as a primary pest of apple throughout the world. And it can be argued that codling moth has historically been the greatest threat to tree fruit production due to its endemic orchard presence, constant exposure and development of cyclical resistance to insecticide programs. During the 2016 harvest we observed very high levels of fruit infestation in Hudson Valley apple, ranging from 2% to 40% injury in commercial production, bringing a level of uncertainty to the effectiveness of the materials in our toolbox.

Management: We have passed the window for use of pheromone trapping to ‘confuse’ the initial wave of second generation CM adults in the mid-Hudson Valley. As such, are too late to effectively control this second generation CM through mating disruption unless it was applied earlier in the season.

The use of Rimon 0.83EC is most effective prior to egg laying, which too has come to pass and would be less effective applied for control of CM. We are now left with the remaining options for managing this insect using contact and feeding insecticides including granulosis virus.

A number of products are available for use in New York State. In blocks of high fruit infestation from codling moth in 2019, a possible cause may have been the use of materials ineffective against the worm during the three generation emergence periods of the larval stage, most notably the 3rd generation in September. The possibility of frequently used insecticides slipping in efficacy is also a possibility.

Presently for managing the codling moth we have standard ‘older’ classes of insecticides that include the Organophosphate, Carbamates, Pyrethroids and Pyrethroid pre-mixes that are still effective, possibly providing efficacy against the adults in the evening as codling moth female adults lay their eggs from dusk to dawn. The Neonicotinoid Assail, Anthranilic Diamides that include Altacor and Exirel, and Spinosyns including organic Entrust and conventional insecticide Delegate are very effective at managing the codling moth.

Assail, Imidan , the pyrethroids, Exirel and pre-mix formulations are also labeled for apple maggot and should be considered to address both insect pests at this time.

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 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 within 3-7 days, and dies shortly thereafter. The decomposing 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.

Codling moth granulosis virus formulations include Cyd-X, Cyd-X HP, Madex HP by Certis; Carpovirusine by Arysta LifeScience. Cyd-X 0.06SC is applied @ 0.25-0.4 qt/acre and Carpovirusine 0.99SC @ 0.25-0.4 qt/acre.

Conventional material options are listed in the Cornell Guidelines for both insect pests (Codling Moth and Apple Maggot).