Codling moth injured apple fruit. Photo: G. Krawczyk, Penn State
Codling moth and Oriental fruit moth issues
The third generation codling moth adults will be active and potentially depositing eggs until at least the mid September, while OFM larvae can infest fruit as late as in the mid October. The higher the temperatures during September and October, the more likely the CM /OFM new infestation may happen. In most orchards, no control is currently needed, as earlier activities likely eliminated the threat from these two pests. However, if the pheromone traps located in orchards are still detecting activity of CM and/or OFM moths, additional management may be necessary to avoid worms in fruit at harvest. With the harvest in mind, only products with a short Pre-Harvest Interval can be used. Most of products recommended for the late season control of BMSB (see the list under the BMSB update), also have good activity against CM/OFM complex, however the CM/OFM specific products such as Altacor ®, Delegate® or Exirel® will not control BMSB. If only CM/OFM need to be controlled, an organically approved product Madex HP (Cydia pomonella granulosis virus, CpGV) also offers effective option against CM and OFM, while Cyd-X HP will control only CM. Also, although it is still somehow experimental use, sprayable mating disruption products Checkmate OFM-F and Checkmate CM-F should disrupt the mating of both pest species and reduce the potential for finding CM and OFM injured fruit at harvest.
Codling moth larvae feeding inside the fruit (left), and CM adult in pheromone trap (right).
Brown marmorated stink bug update
As it usually happens about this time of the season, during last two weeks we started to observed increased numbers of brown marmorated stink bug nymphs collected in BMSB monitoring traps placed around commercial orchards. Traps placed on or under the trees located on the border of woods as well as traps placed in the first row of orchards, which rarely collected stink bugs for most parts of this season, now started to collect many BMSB nymphs and adults. Since not every orchard will experience the same pressure from BMSB, cautious scouting and monitoring of the orchard surrounding vegetation should be very helpful in deciding if any special stink bug control treatment(s) is necessary. It is important to remember that the absence of stink bugs during the season, does not guarantee that they will not become abundant in the orchard just before harvest. BMSB is not an orchard resident pest and whatever management tactics were utilized to control BMSB during the season in any particular block, cannot guarantee or prevent new individuals from infesting/re-infesting the site just prior to the harvest.
Although during this year the movement from summer hosts to orchards is happening later than during previous years, it still represents a significant danger to fruit. It is not too late to deploy BMSB monitoring traps into your orchard, at least in the areas of possible highest BMSB pressure. The BMSB monitoring lures and traps from AgBio 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.
The incessant feeding of nymphs and adults can potentially cause significant injury especially to later maturing apple cultivars. Fresh injuries from stink bug feeding are initially almost undetectable, but after 10 to 14 days, the injury (i.e., corking) should become very apparent. If BMSB feeding occurs just prior to harvest, it is quite possible that at harvest time, affected fruit will exhibit no visible signs of injury, but the characteristic depression on the fruit surface will develop later, during the storage time. Late season feeding can be very intensive, as adult stink bugs are trying to accumulate enough resources to survive the winter.
Insecticides still remain the most effective BMSB management tool, however none of the available products will be able to protect fruit perfectly from at least some damage. Early detection of feeding BMSB will help to limit the damage but not eliminate it completely. The most effective products will control only the individuals present in the orchard at the time of the application (i.e., direct contact activity), but they will not stop newcomer BMSB adults from at least initially probing the fruit as each probing equals an injury. Most of the effective insecticides provide only a few days of residual protection. The results of our residual bioassays revealed that most of the recommended insecticides provide sufficient residual control of BMSB nymphs for at least 7 or even 12 days after the application (higher rates of product usually provide longer residual activity).
(Left to Right) Container type BMSB monitoring traps from Ag-Bio Inc. and Sterling International, and sticky traps for BMSB monitoring from AlphaScent Inc. and Trece Inc.
The following list includes insecticides with good activity against BMSB adults and nymphs, as well as the pre-harvest (PHI) information for each product. The BMSB adult efficacy rating is based on our laboratory and field bioassay results conducted at Penn State's Fruit Research and Extension Center.
- Acetamiprid (IRAC Group 4A) (Assail 30 SG); 7-day PHI on pome and stone fruit, no more than 32.0 oz of formulated product per acre per season, BMSB adult direct contact mortality at 72 hours - about 87%.
- Bifenthrin (IRAC Group 3) (Brigade WSB, Bifenture EC, Bifenture 10DF); products are registered under Special Section 18 Emergency Exception Registration for the 2017 season – 14-day PHI on apples, peaches and nectarines. BMSB adults direct contact mortality and BMSB nymphs residual mortality (at 7 days) were at 100 percent.
- Clothianidin (IRAC Group 4A), (Belay); 7-day PHI on apples and pears; 21-day PHI on peach, no more than 0.2 lb AI per acre/per season is allowed, BMSB adult direct contact mortality at 72 hours - 100%.
- Dinotefuran (IRAC Group 4A) (Scorpion, Venom,); products are registered under Special Section 18 emergency registration until Oct 15, 2017; 3 days PHI on pome and stone fruit, no more than 2 applications of this active ingredient per season, BMSB adult direct contact mortality at 72 hours – about 98%.
- Fenpropathrin (IRAC Group 3) (Danitol); 14-day PHI on apples and pears; 3 days on stone fruit. No more than 0.8 pound of AI is allowed per acre/season, BMSB adult direct contact mortality at 72 hours) – about 82%.
- Imidacloprid (IRAC Group 4A) (Admire Pro, Leverage (imidacloprid mix with beta- cyfluthrin)); Admire Pro has 7-day PHI on pome fruit, 0 days PHI on stone fruit, no more than 0.5 lb AI per season; Leverage SC 360 has 7 day PHI on pome and stone fruit, no more than 0.044 lb AI per acre of beta cyfluthrin and/or 0.088 lb AI per acre of imidacloprid. Admire Pro BMSB adult direct contact mortality at 72 hours – about 87%; while for Leverage the BMSB adult direct contact mortality at 72 hours – about 93%.
- Lambda-cyhalothrin (IRAC Group3) (Warrior II with Zeon Technology, Taiga Z); 21-day PHI on pome fruit, 14-day PHI on stone fruit, BMSB adult direct contact mortality at 72 hours – about 72%.
- Methomyl (IRAC Group 1A)(Lannate); 14-day PHI on apples; 7 days on pears; 4 days on peaches; 1 day on nectarines (PA only). On apples no more than 4.5 pounds of AI/acre is allowed, on peaches no more than 5.4 pounds of AI per acre/season; on pears no more than 1.8 pounds of AI per acre/season, BMSB adult direct contact mortality at 72 hours – about 90%.
- Thiametoxam (IRAC Group 4A) (Actara, Endigo); 35-day PHI for both products on pome fruit, 14-day PHI on stone fruit, no more than 0.2 lb AI lambda-cyhalothrin containing products or 0.172 lb AI (stone fruit) or 0.258 lb AI (pome fruit) of thiametoxm containing products per season. For Actara the BMSB adult direct contact mortality at 72 hours – about 95%, for Endigo the BMSB adult direct contact mortality at 72 hours - 100%.
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.