Higher numbers of new JB adults are usually noticed following rain events, with moisture helping the JB adults exit their soil shelters. Also, observations of the grape plants and some apple cultivars such as Honeycrisp or Enterprise help in early detection of increasing JB populations. Japanese beetle adults seem to prefer those plants and colonize them faster than other potential hosts. If insecticides are needed to manage JB excessive damage, products recommended for the control of brown marmorated stink bug (BMSB) should also provide effective control of JB. If the control of BMSB is not necessary, and only JB needs to be controlled, insecticides containing carbaryl (such as in Sevin®) should provide good control of JB.
Japanese beetles injuries on of apple tree foliage. Photo: G. Krawczyk, Penn State
Brown marmorated stink bug (BMSB)
If brown marmorated stink bug nymphs are present in any orchard, the insecticide treatment is the only effective way to prevent injuries to the fruit. During last week observations, we noted an increased presence of BMSB nymphs in apple, peach and cherry orchards. While the BMSB control in apples and peaches by now become a standard practice, the necessity of BMSB management in cherries is somehow confusing. Although the harvest of cherries is almost completed, the cherry trees even without fruit will still support the developing BMSB populations, which later in the season can contribute to the BMSB invasion into neighboring stone and pome fruit orchards.
The list of effective insecticide options against BMSB includes limited number of insecticides: pyrethroids (IRAC Group 3A) such as Bifenture® EC and 10DF and Brigade® WSB (the same AI, bifenthrin), Danitol® (fenpropathrin), and Warrior® (ƛ-cyhalothrin); neonicotinoids (IRAC Group 4A) such as Actara® (thiametoxam), Assail® (acetamiprid), Belay ® (clothianidin), Venom® and Scorpion® (dinotefuran); and one carbamate product (IRAC Group 1A), Lannate® (methomyl).
The on-site monitoring still remains the best indicator if treatment targeting BMSB are necessary. 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.
Brown marmorated stink bug second and third instar nymphs (left) and BMSB adult (right). Photo: G. Krawczyk, Penn State
Pear psylla (PP)
Pear psylla (PP) populations are still present in many local pear orchards especially on still growing terminals located inside the tree canopy. Nymphs and adults of this pest can be effectively controlled by treatments of Danitol®, or Endigo®, or Centaur® WDG, or Exirel ®, or Delegate® plus adjuvant. While still effective, additional applications of Surround may not be too practical anymore as the product residue will most likely to be highly visible at harvest. Excellent coverage of the entire tree canopy including all still growing terminals with effective products is crucial for the successful pear psylla control.
Pear psylla nymph (left) and adults (right) on pear foliage. Photo: G. Krawczyk, Penn State
Wooly apple aphids (WAA)
Early July is a good time to re-evaluate orchards for the presence of wooly apple aphids (WAA). If WAA are observed in the orchard, application(s) of Movento® or Diazinon® should provide effective control of this pest. Movento is translaminar within plants and provides good systemic activity against live WAA but for the maximum efficacy of this product, an addition of surfactant is required. Effective WAA biological control agents include syrphid flies Heringia calcarata and Eupeodes americana and tiny wasp Aphelinus mali, however their presence in orchards is easily disrupted by applications of broad spectrum insecticides such as pyrethroids or neonicotinoids applied for the control of various other fruit pests.
Wooly apple aphid fresh (left) and advanced (right) colony on apple branch.Photo: G. Krawczyk, Penn State
Moths and leafrollers
As the first generations of codling moth (CM), tufted apple bud moth(TABM) and obliquebanded leafroller (OBLR) are completed and the second generation of Oriental fruit moth (OFM) is also almost concluded, early to mid-July is a perfect time to check for any signs of injuries caused by these pests during the early part of the season. If fruit or foliage injuries are detected, a special attention need to be placed to prevent their re-occurrence later in the summer. At this time of the season, the Oriental fruit moth injuries are most easily detected by searching for shoot flagging on peach and apple trees (Photo 1 below) or a frass produced by feeding larvae usually located at the fruit calyx or stem end (Photo 2 below). If present, the codling moth injury which can be found only on apple or pear fruit, should be easily detected as visible small tunnels starting usually on the side of the fruit, with some frass around it and leading to the seed chamber. Tufted apple bud moth larvae usually create a shelter from an older leaf and the larva feeds inside the shelter (Photo 3 below), while the OBLR larvae usually feed in the rolled leaves on the top of the terminal (Photo 4 below).
The visual observations of currently existing injuries combined with the on-site pest monitoring utilizing sex pheromone traps should be used to decide if management treatments are needed for the next generation of these pests, which will become active later in July and/or August. The male moth captures of CM, OFM, TABM and OBLR in the pheromone traps should also be helpful in deciding about the best timing for the control activities.
Photo 1. Injury on peach (left) and apple (right) shoots caused by early season Oriental fruit moth larvae. Photo: G. Krawczyk, Penn State
Photo 2. Apple fruit injured by the Oriental fruit moth larvae with frass at the calyx end of fruit (left) and fruit injured by codling moth on the side of the fruit (right) with San Jose scale symptoms near the calyx end (four small red dots with bright center.) Photo: G. Krawczyk, Penn State
Photo 3. Tufted apple bud moth shelter created by the feeding of the first generation larvae. Photo: G. Krawczyk, Penn State
Photo 4. Leaf shelter on the top of the terminal made by developing obliquebanded leafroller larvae. Photo: G. Krawczyk, Penn State
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 Toolbox.