Plum Curculio adult on young apple fruit. Photo: G. Krawczyk, Penn State
Oriental Fruit Moth (OFM)
The Oriental fruit moth (OFM) degree-day based developmental model (courtesy of SkyBit Inc.), forecasts about 95 percent OFM egg hatch around May 7th. What it means from practical perspective, roughly 95 percent of OFM larvae are already inside growing peach and apple terminals or inside developing fruit. Although the OFM flight differs from orchard to orchard and area to area, any insecticide used at this time for OFM control will likely be effective only on the remaining 5 percent of the OFM larval population. Larvae already feeding inside growing branch terminals and inside fruit are protected from insecticides and will not be controlled by any insecticide treatment.
Oriental fruit moth injuries on peach terminal. Photo: G. Krawczyk, Penn State
Codling Moth (CM) and Tufted Apple Budmoth (TABM)
In the Biglerville area, the sustained flight of codling moth (CM) started on April 25th (biofix) while for tufted apple budmoth (TABM) biofix was established on May 1st. If use of mating disruption dispensers is planned for control of CM, this is the last time to place dispensers in the orchards for season long effective control of this pest. It is still too early for use of insecticides to control either CM or TABM. The optimal timing for the first insecticide application against codling moth should be scheduled at about 250-350 DD50 (degree days base 50°F) after the biofix. With colder weather in the forecast for the next 5-7 days, this timing for the CM control is expected to occur around mid-May.
Fresh codling moth injury on apple. Photo: G. Krawczyk, Penn State
Plum Curculio (PC)
In contrast to the CM and OFM situation, plum curculio (PC) adult weevils are present in the orchards and with the first few days of warmer weather, are set to cause damage to developing stone and pome fruit. For effective control of this pest, the PC model from Cornell University recommends continuous insecticide coverage until cumulative accumulation of 308 DD50 after petal fall. With this year's weather, the insecticide treatments against PC may be needed until the traditional second cover timing. The most effective insecticides for the PC control include Avaunt, Imidan, Assail and Exirel.
Brown Marmorated Stink Bug (BMSB)
During last two weeks we started to capture brown marmorated stink bug adults in traps placed around fruit orchards. Although the numbers of captured BMSB are still very low, traps baited with one of the three most common lures: Stink Bug Xtra Combo (from Ag-Bio,Inc.), TR-BMSB plus TR-GSB 3237(from Trece Inc.) and Stink Bug Rescue lure (Sterling International, Inc.) seems to provide solid information on potential movement of adults into orchards. If Assail is used against plum curculio, it should also provide good control of BMSB.
Brown marmorated stink bug adult and nymph on foliage. Photo: G. Krawczyk, Penn State
Bifenthrin, the active ingredient belonging to pyrethroid insecticide group (IRAC Group 3A), received a special Section 18 Emergency Exemption Registration from US EPA (April 20, 2017). Bifenthrin can be applied up to two times per season, with at least 30-day interval between applications. Three commercial products are available for Pennsylvania growers to use against brown marmorated sting bug: Brigade® WSB, Bifenture® EC and Bifenture® 10DF. This Section 18 Emergency Exemption registration for products containing bifenthrin will expire on October 15, 2017.
All pheromone traps for monitoring the most common fruit pests should already be in place in orchards. If hand applied mating disruption materials (Isomate, CheckMate or CideTrak products) are planned for the control of CM, dogwood borer, peach tree borer or lesser peach tree borer, it is not too late to place pheromone dispensers in orchards. Since the flight of the first generation OFM is almost over, the mating disruption products targeting OFM should be placed in orchards before the start of the second generation flight.
In the Biglerville area (Penn State FREC orchards), the 2017 season biofix for Oriental fruit moth was established on April 05; spotted tentiform leafminer on April 01, codling moth on April 25, and tufted apple bud moth on May 01. Biofix for obliquebanded leafroller is not yet established in the south-central PA.
The insect pest control updates presented are for South-central Pennsylvania based on observations in Adams County. To view the insect hatch and trapping data for all major insect pests, please visit the Penn State Fruit Research and Extension Center (FREC) website. For control recommendations, refer to the Insect and Mite Control Toolboxes.