Brown marmorated stink bug injury on apple. Photo: G. Krawczyk, Penn State
No control is necessary for any of the above pests, unless the pheromone traps placed in orchards detect the extended flight of the codling moth, the so called "second peak", as we just observed in our apple orchards at the Penn State Fruit Research and Extension Center (FREC).
In such situation when high numbers of codling moth (CM) adults are still collected in the pheromone traps, an additional insecticide application directed against codling moth might be necessary. The next best timing to control both leafroller species will occur after the start of their second generation flights, usually in late July or early August. Pheromone traps provide the easiest tool to accurately assess the pest pressure in orchards and to answer the question "if and when" active pest management is needed. Combined with the egg hatch developmental models, the trap information helps to decide when the treatment(s) should be applied to be the most effective.
Left: Tufted apple bud moth in pheromone trap. Right: Obliquebanded leafroller injured new growth on apple tree. Photos: G. Krawczyk, Penn State
Oriental fruit moth (OFM)
According to egg hatch models provided by the SkyBit Inc. for the Biglerville area, the second generation Oriental fruit moth (OFM) egg hatch is currently under way (50 percent egg hatch as of June 22). In most orchards the flight of the second OFM generation is usually very low and no special control is required, however if more than 15 OFM males are collected per trap/week, then special OFM targeting insecticide application may be warranted.
Spotted wing drosophila (SWD)
Based on our experience from the last few seasons, end of June is a good time to search for the first male adults of spotted wing drosophila (SWD). Growers with late sweet cherries and sour cherries as well as blueberries and black raspberries should pay very close attention to possible movement of this pest into their plantations. Traps are very effective tool to detect increasing populations of SWD.
Left: Spotted wing drosophila hiding under a raspberry. Photo: K. Demchak, Penn State. Right: Spotted wing drosophila male. Photo:A. Surcica, Penn State
Brown marmorated stink bug (BMSB)
It is time to start again seriously plan for the activities related to the monitoring and management of the brown marmorated stink bug. The BMSB monitoring lures and traps from Ag-Bio Inc., AlphaScent Inc., Sterling International, and Trece Inc. are commercially available either directly from the manufacturer, specialty stores or stores like Walmart, Lowe's or Home Depot. Although different lures and trap designs are available, all of them should provide adequate information about the presence or absence of the stink bugs and potentially about the necessity of a specific stink bug management treatment.
The most popular BMSB traps are the clear plastic sticky traps (Photo 1) and the pyramid shaped traps with a bug capturing container (Photo 2). The clear sticky traps are very effective in monitoring BMSB adults, but are not as effective in monitoring BMSB juvenile stages. The container based traps are initially more difficult to assemble (and more expensive) but, if placed in direct contact with a vegetation, they will provide very accurate monitoring for both, BMSB nymphs and adults. Additionally, under higher pressure from stink bugs, the container traps can be easily emptied from collected stink bugs and reused, while the sticky traps will need to be replaced. Although each trap and lure combination vary in the efficacy of captured stink bugs, all of them are excellent source of information about the actual local presence of BMSB.
Photo 1. Brown marmorated clear sticky traps baited with BMSB lures from various manufacturers: left to right--AlphaScent, Ag-Bio, and Trece. Photos: G. Krawczyk, Penn State
Photo 2. Brown marmorated stink bug container type traps: left to right--Dead-Inn stink bug trap (from Ag-Bio Inc.), Rescue stink bug trap (from Sterling International) and Dual funnel trap (from Trece, Inc.) Photos: G. Krawczyk, Penn State
The BMSB adults are strong migratory pests, capable of moving long distances and aggregating in any location. Newly arrived BMSB adults, if not detected and controlled, are capable to cause a serious fruit injuries in orchards. Unfortunately, since the injuries caused by the BMSB adults are difficult to detect until about 10-14 days after the feeding, often the stink bugs may be already gone from the site before the feeding symptoms are detected. On another hand, the detection of BMSB nymphs in traps, almost always warrants the necessity of immediate BMSB control, likely with an effective insecticide application. Brown marmorated stink bug nymphs, in contrast to BMSB adults, are resident pests in the orchard. If the BMSB nymphs are not controlled, starting from the second instar, they will continuously feed and unfortunately, every time nymphs are feeding, the fruit injury is created, which will result in deformed fruit and/or corky area just under the skin of the fruit. As with most insects, the BMSB nymphal development is weather depended but usually it takes about five weeks for the BMSB nymph to become adult.
Clear sticky trap with BMSB adults (Fall 2016) Photo: G. Krawczyk, Penn State
The list of effective insecticide options is limited and includes products only with few distinctive modes of action: pyrethroids (IRAC Group 3A): Bifenture® EC and 10DF and Brigade® WSB (the same active ingredient, bifenthrin), Danitol® (fenpropathrin), and Warrior® (cyhalothrin); neonicotinoids (IRAC Group 4A): Actara® (thiametoxam), Assail® (acetamiprid), Belay ® (clothianidin) and Venom® and Scorpion® (the same active ingredient - dinotefuran); one carbamate product (IRAC Group 1A), Lannate® (methomyl) and some products including combinations of two different insecticide chemistries such as in Endigo® or Leverage®.
While trying to limit the impact of BMSB on fruit, please remember about potential negative impact of BMSB effective insecticides on various beneficial organisms and native bees present in the orchard, seasonal limits for the number of insecticide applications per season and the mandatory pre-harvest intervals of various products.
Seasonal Activity of Fruit Pests
2017 season weekly average captures of adult moths in pheromone traps located at the Penn State Fruit Research and Extension Center, Biglerville, PA (Adams County)
Abbreviations: RBLR - redbanded leafroller; STLM - spotted tentiform leafminer; OFM - Oriental fruit moth; CM - codling moth; TABM - tufted apple budmoth; OBLR - obliquebanded leafroller; DWB - dogwood borer; PTB - peach tree borer; LPTB - lesser peach tree borer
Accumulated degree-days base 43°F from Jan 01 for each reported year (courtesy of SkyBit, Inc.)
The accumulated degree-days for the last date of the current year (July 01) mentioned in the table are based on the weather forecast.