Control of Fruit Insect Pests During the Early Summer Season

The adults of the first generation oriental fruit moth (OFM), codling moth (CM), tufted apple budmoth (TABM) and obliquebanded leafroller (OBLR) are active now, and while the flight of the first generation OFM is almost over, the remaining pest species are very active right now. The first generations codling moth and tufted apple budmoth are depositing eggs and will continue for the next few weeks. OBLR will start egg deposition within the next few days, and the larvae will become visible in the next couple of weeks.

The first complete or two halves of insecticide application for the control of CM should have already been applied in most orchards. The second and possibly third CM applications should coincide almost perfectly with the expected timings for effective control of TABM and OBLR. The first and second week of June should be ideal timing for the second CM and first TABM treatments (the exact timing will vary by location). Then, about two weeks later, if necessary, CM, TABM, and OBLR can be controlled again at the same time (first treatment timing against OBLR, second against TABM and possibly third CM treatment). If Altacor®, Exirel®, Besiege®, Voliam® Flexi, Delegate®, Intrepid® or Rimon® are to be used for TABM and OBLR control, usually 1 or 2 complete, precisely timed applications of those products per brood are recommended.

Applications of Altacor, Exirel, Voliam or Delegate, will also provide excellent control of codling moth neonates if they are still present in orchard. If applying two complete sprays dedicated only against TABM, the first application should be applied at about 10-30 percent egg hatch followed by a second application (if necessary) at about 60-70 percent egg hatch.

The low rate of Intrepid (10-12 oz/acre) also should provide excellent control of TABM larvae, but this rate of Intrepid will not control codling moth or Oriental fruit moth. If only one complete application of insecticides is needed against TABM, this single application can be made at 30-40 percent egg hatch.

Since young OBLR larvae prefer to feed inside growing terminals, the insecticide coverage of fresh growth plays a critical role in the control of this pest. The better the coverage, the better the larval control achieved. Additional insecticides recommended for the control of both leafrollers during this time of the season also include Bacillus thuringiensis products (most are approved for organic production).

The weekly moth captures data at the Fruit Research and Extension Center (FREC) for major fruit pests are posted at the FREC website.

Weekly applications of organically approved codling moth granulosis virus as in Cyd-X® or Madex HP® will provide good control of codling moth but will not impact leafrollers or other insects, including beneficial species.

Obliquebanded leafroller injured growing terminal on apple (left) and tufted apple budmoth larvae feeding on foliage (center) and fruit (right). Photo: G. Krawczyk, Penn State

Oriental fruit moth injuries on a peach terminal (left) and apple fruit (center), and CM injuries on apple fruit (right) Photos: G. Krawczyk, Penn State

Pear psylla control

The recent warm weather stimulated a big increase in populations of pear psylla (PP). An action threshold of 1 nymph per leaf is recommended. If chemical control is required, neonicotinoids such as Admire® Pro (7 fl oz/ac), Actara® 25WP (5.5 oz/ac), Assail® 30SG (8 oz plus a quart of summer oil) or Endigo® ZC (6.0 fl oz/ac) should be effective for psylla control. In our recent studies, we also observed high efficacy of products such as Exirel (20.5 oz/ac) and Delegate (7.0 oz/ac) on various stages of pear psylla.

Other PP management insecticide options with different modes of action include applications of Centaur® (34.5 oz/ac), Sivanto® (14 fl oz/ac) or Movento® (9.0 fl oz/ac). Good coverage of Surround could also help to control pear psylla, although the product residues on fruit may create potential marketing issues.

Apple aphid/spirea aphid complex

New colonies of apple aphid and spirea aphid are being observed in many orchards across Pennsylvania. The aphid colonies are observed largely on new terminals with fresh foliage. In most cases, the aphids should be controlled very effectively by natural enemies such as syrphid larvae, lacewing larvae, aphid midge, ladybird adults and larvae, and some Braconids wasp. If an average of more than 4.2 leaves per shoot are infested by aphids and less than 20 percent of colonies have predators within the colony, an insecticide application may be needed to lower the aphid population. Please remember to use pesticides with low toxicity to the predators.

Apple aphid/spirea aphid colony of new apple terminal (left); predatory syrphid larvae feeding on aphids (center) and lady beetles (right) Photos: G. Krawczyk, Penn State

Periodical cicada in the south-western part of Pennsylvania

For the last two weeks, growers with orchards located in the south-western part of Pennsylvania (Allegheny, Armstrong, Beaver, Cambria, Clarion, Crawford, Fayette, Forest, Huntington, Indiana, Lawrence, Mercer, Venango, Washington and Westmoreland counties) are observing increased numbers of the Brood VIII periodical cicada adults.

Within 7 to 10 days after the males begin "singing," the female cicadas start depositing eggs in small pockets located primarily on young branches. The cut to create the pocket to deposit eggs and the consecutive dieback of those branches are the main visible damage caused by periodical cicadas. After hatching, the larvae will drop to the ground and spend the next seventeen years feeding on roots of plants. If necessary, the management activity should be directed mostly to protect young trees.

Although the mechanical barriers such as nets are very effective in protecting individual trees, on larger areas insecticide applications provide the most effective control of periodical cicadas. Broad spectrum insecticides from the pyrethroids (e.g., Asana, Danitol, Warrior) or neonicotinoids (e.g., Actara, Admire Pro, Assail) should be very effective against cicadas, providing both direct and residual activity. Under heavy extended pressure from periodical cicada, multiple applications of insecticides may be necessary. For more information, please see Penn State's Periodical Cicada Factsheet.

Periodical cicadas on an apple tree (left and right) and injuries caused by egg deposition by cicada on a young branch (center). Photos: G. Krawczyk, Penn State

Brown marmorated stink bug update

Brown marmorated stink bug (BMSB) overwintering adults have typically completed their movement away from overwintering shelters. This year the numbers of BMSB adults appear to be lower than in previous years, and in a majority of the orchards, no special stink bug control activities are required at this time. If eggs or nymphs become detectable, application of effective insecticides will be necessary to prevent early-season injuries to fruit. Early season fruit injury usually results in severe deformations of fruit at harvest, impacting marketability. As the eggs and nymphs are expected at any time now, this may be a perfect time to restart BMSB monitoring in fruit orchards.

EPA Section 18 Emergency Exemption Registration for products containing bifenthrin for use against the brown marmorated stink bug

This year, as during last few years, the active ingredient bifenthrin, belonging to the group of pyrethroids IRAC Group 3A, received a special Section 18 Emergency Exemption Registration from US EPA (May 24, 2019). Three commercial products with bifenthrin are available for growers to use against brown marmorated stink bug: Brigade® WSB (FMC Corporation, Philadelphia, PA), Bifenture® EC (United Phosphorus Inc., King of Prussia, PA) and Bifenture® 10DF (United Phosphorus Inc.).

According to the product labels Brigade WSB is recommended at the rate from 12.8 to 32.0 oz, Bifenture EC at the rate of 5.12 to 12.8 fl oz, and the Bifenture 10DF at the rate of 12.8 to 32 oz per acre. Bifenthrin can be applied up to two times per season, with at least 30 days interval between applications. Growers who plan to use products containing bifenthrin need to have the Section 18 label available before application. Under the Section 18 Registration, products containing bifenthrin can be used on apples, peaches, and nectarines (bifenthrin already has a full registration on pears) up to 14 days before harvest (14 d PHI, 12 h REI).

Please remember, another formulation of bifenthrin, Brigade 2EC is not included in the Section 18 Emergency Registration, and this product is not registered for use on fruit except for pears. The section 18 emergency exemption registration for products containing bifenthrin will expire on October 15, 2019.