Synopsis: Although Plum Curculio (PC) activity is in decline, any curculio remaining in the orchard will usually not move to other locations as we near the end of PC migration. However, Plum Curculio will need to be controlled (ie provided effective residual in the orchard) until 308 Degree Days (DD) have accumulated after petal fall. We are presently at 288DD in Highland NY. Confirm that the predicted residual coverage, based on 10-14 days of residual from the last spray, will provide fruit protection until the 308 Degree Day accumulations are met.
NEWA (Highland, NY Station) predicts this to occur on the 11th June at the Hudson Valley Research Lab. To determine DD accumulations for Plum Curculio Log in to the NEWA station nearest your orchard. If PC are continuing to migrate to your site (<308DD) and you are out more then 10-14 days or have had above 0.5" rain over the past 5-10 days, an application to manage PC is warranted. You will also need to manage Codling Moth at this time.
Codling Moth (CM) The fist peak of adults has has been reached and will continue to emerge, mate and lay eggs over the next few weeks.
The first sustained flight and Biofix for CM was the 17th of May and as of today (8 June) we have accumulated 308 DD50 using the NEWA model.
The first eggs were laid at about 50 DD from the biofix, with codling moth egg hatch began at 220 DD or (June 2nd at the HVRL). Adult flights are relatively heavy during this period and the majority of eggs are likely to hatch, so control is critical at this time.
We will need to consider a second spray, 10-14 days after the initial spray, to provide protection during this critical time period. The first application should have been made, approximately on the 2nd of June, timed at first hatch. Using a June 2nd application for first emergence of CM, then the 12th to 14th of June is the next window for codling moth management.
Important Consideration: We are likely seeing a reduced level of susceptibility of codling moth to our insecticide tools. In high-pressure orchards and orchards with perennial CM injury and infestations, it may be particularly important to apply other classes of materials to replace organophosphates or synthetic pyrethroids this season (Management Options Below). Materials containing Chlorantraniliprole (*†Altacor) or Cyantraniliprole (*†Exirel) have excellent activity against CM, have had less exposure to CM and thus are a good fit for first generation control and sustainable resistance management.
Observations in the research orchard…
* San Jose Scale crawlers predicted for next week…no crawlers observed on black electrical tape to date
* Commercial orchards with PC injury where Assail was used at 1st cover.
* Increasing lepidopteran larva and tarnish plant bug feeding injury to developing fruit.
The 2019 Cornell Pest Management Guidelines for Commercial Tree Fruit Production can assist in decision making during the growing season with on-line access available.
Management for Plum Curculio: After the whole orchard petal fall application is made, border applications for PC management can made to reduce migratory adults until the whole orchard application for Codling Moth needs to be applied. This may provide you the additional time necessary to more precisely target codling moth.
Generally, of the neonicotinoid class, Actara 25WDG (Thiamethoxam) @ 4.5-5.5 oz/acre is the only material in this class effective against for plum curculio. It has translaminar or systemic activity that reduce foliar feeding insects such as aphids (Green & Rosy Apple Aphid (RAA)) and leafhopper.
Avaunt (Indoxacarb), is a broad-spectrum oxadiazine labeled in apples and pears against plum curculio (High Activity), apple maggot, and European apple sawfly, with some activity also on Lepidoptera such as codling moth (Moderate Activity), oriental fruit moth and leafminers, as well as leafhoppers. The active ingredient is activated by the insect to an insecticidal form only upon ingestion or absorption through the cuticle, after which it causes paralysis by interference with the sodium flow into nerve cells. It has generally slight to no effects on beneficial insects and mites. Avuant 30WDG at the high rate of the 5-6 oz./A range will manage PC with varying degrees of activity against the secondary pest spectrum.
The pyrethroid class is effective against the PC for 7-14 days using high labeled rates. They generally reduce codling moth. However, the use of this class will disrupt the beneficial mite complex, specifically the predatory phytoseiid mite Amblyseius fallacis and Typhlodromus pyri.
Management for Codling Moth: The addition of the neonic’s, such as Assail 30SG at 2.5-4 oz/acre, or the use of Exirel (cyantraniliprole) at 13.5-20.5 fl.oz./acre will provide the additional broad spectrum activity needed for Codling Moth Management. Admire Pro 4.6SC (imidacloprid) at 2.8 fl.oz./acre, along with Assail and Exirel will provide RAA management, including green aphids and leafhopper.
The active ingredient for Exirel is cyantraniliprole, the anthranilic diamide class (Group 28), in the same class as Altacor (Rynaxypyr) with a broad spectrum of activity, which has shown strong efficacy against plum curculio. The addition of post bloom applications of Movento 240SC at 6-9 fl.oz./acre is also very effective against RAA, reduces San Jose scale residing in the trees and reduces the incidence of wooly apple aphid that can develop late into the season due to BMSB management use of pyrethroids that reduce predatory beneficial insects.
The use of pre-mix insecticides should be strongly considered here.
Additionally, note that Thiamethoxam is limited to a maximum seasonal total of 0.172 lb/A, regardless of the formulation, which can complicate mixing & matching of products during the season.’ It’s very important to know that if a full rate of thiamethoxam is essential for plum curculio management in high pressure blocks, then a pre-mix may not be the best option.
