Apr 28, 2015
Penn State: Spring management recommendations for pests

This year, the forecasted accumulation of degree days base 43° F for April 28, 2015, is even lower than the corresponding number for 2014. As the colder weather influences the general development of insect pests, the low temperatures are influencing moth activities and pushing this year’s biofixes to the latest dates on record. The 2015 biofixes for redbanded leafroller occurred on April 11, spotted tentiform leafminer on April 18, while as of April 22 we still did not have the biofix for Oriental fruit moth (although some individual moths were observed in traps after the warm day on April 18). Biofixes for codling moth and tufted apple bud moth are also expected to be delayed; however they should occur sometime during the bloom of apples. Establishing a correct biofix, used as the starting point for the insect developmental models, is crucial later during the season for the timing of all management activities.

BMSB

Our visual observations during the last weekend (April 18) conducted inside various structures detected increased activity of brown marmorated stink bug; however so far no adults were found feeding on outside vegetation. Brown marmorated stink bug adults overwintering inside houses appear to have survived winter in relatively good shape and are getting ready to initiate feeding on any green plants available.

Protection of pollinators

In order to maximize the protection of wild pollinators and honey bees, we continue to recommend avoidance of insecticide applications before the bloom. Most insects present in the orchard before bloom can also be effectively managed by the insecticide application(s) at the petal fall timing, which remains one of the most important treatments, setting the tone for the rest of the season. The insect pest complex present in orchards around bloom time such as obliquebanded leafroller, European apple sawfly, rosy apple aphid, Oriental fruit moth or plum curculio can be controlled at and after petal fall. Due to valid concerns with the possible pesticide direct and sub-lethal effects on the population of honey bees and other native pollinators, it is strongly recommended that growers refrain from using insecticides until bees are completely removed from orchards.

The group of pests including Oriental fruit moth, plum curculio, European apple sawfly, oblique banded leafroller, and redbanded leafroller can be effectively controlled by broad-spectrum insecticides such as Imidan, or Assail, or Calypso or Avaunt if applied shortly after bloom. Older neonicotinoids (Admire Pro and Actara) applied at the petal fall timing will provide good control of aphids and leafminers but they will not be effective against many other pests. However both products provide good contact activity against brown marmorated stink bug and plum curculio (if present in the orchard). If only leafrollers, Oriental fruit moth and leafminers are the intended target(s) of the petal fall treatment, then an application of Intrepid, or Proclaim, or Rimon should be very effective. If no dormant oil was applied during the pre-bloom period, European red mite populations can be reduced with application of Agri-Mek (or other formulations of this active ingredient) plus a penetrant (e.g., oil) applied at petal fall. Abamectin, the active ingredient in Agri-Mek, still offers good control of European red mite and spotted tentiform leafminer, and fair to good control of white apple leaf hopper. Agri-Mek should be applied before the leaves harden off, generally within 10 days of petal fall. Other acaricides such as Acramite, Envidor, Portal, Kanemite, Nexter or Zeal, although registered mainly for summer mite control can also be considered for mite control at this time of the season. The ovicidal acaricides Apollo or Savey should be applied during the petal fall to first cover period.

Orchard monitoring

It cannot be overstated how important it is to aggressively monitor all insect pests in each orchard, especially with the additional pressure coming from brown marmorated stink bug. Traps with brown marmorated stink bug attractants and sex pheromone traps for at least four main lepidopteran pests: codling moth, Oriental fruit moth, tufted apple bud moth and obliquebanded leafroller should be placed in each part of the orchard managed individually. Correctly identified and monitored insect pests can be controlled much more effectively and at a much lower overall cost if the information from insect traps is used to decide “if” and “when” management activities are necessary.

Mating disruption

Our 2014 field trials comparing various mating disruption products for the control of codling moth and Oriental fruit moth documented continuous usefulness of these products in our orchards. If mating disruption products will be used for the control of codling moth, the pheromone dispensers should be placed in orchards in the beginning of May, but no later than during the early bloom stage on apples (i.e., before codling moth biofix). Although, the best timing for placing Oriental fruit moth mating disruption products is also before the Oriental fruit moth biofix, even delayed placement of Oriental fruit moth mating disruption products should be very effective and reduce seasonal pressure from this pest during later Oriental fruit moth generations. Please see the slide with this article for the assortment of available mating disruption products available for the control of Oriental fruit moth and codling moth.

Good coverage

San Jose scale overwinters as immature blackcaps on the trunks and scaffolds of the tree. The nymphs remain dormant under their waxy covering until the sap begins to flow in the spring, and they continue to feed until bloom. Scales are especially difficult to control on large trees with rough bark. If scales were not controlled during the pre-bloom period, an application(s) of Esteem, Centaur or Movento after bloom (up to second cover) should help in management of this pest. The addition of oil will improve the efficacy of Centaur or Movento, while Esteem can be applied without oil. Similarly to early season mite control, the secret to good scale control is good coverage. Growers should use a minimum of 100 gallons per acre or more depending on the size of their trees.

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Grzegorz Krawczyk, Penn State University


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