Photo 1. Apple fruit injured by first-generation codling moth larvae. Photo: G. Krawczyk, Penn State
Moths of the second generation codling moth (CM), the third generation of Oriental fruit moth (OFM) as well as the second generations of tufted apple bud moth (TABM) and obliquebanded leafroller (OBLR) are either already started or are ready to start their next generation activities.
Codling moth, Oriental fruit moth, Tufted apple bud moth, Obliquebanded leafroller
The juvenile stages of all four species are capable of causing severe fruit injuries detectable at harvest. The CM and OFM larvae are the most common larvae feeding inside fruit (Photos 1 and 2), while the TABM and OBLR are responsible for the injuries on the surface of fruit (Photos 3 and 4). Although the egg hatch developmental models provide a reasonable estimation of the best timings to control each pest, only the site-specific monitoring of each pest population accurately assesses the pest pressure in an individual orchard and should be used to determine “when” and “if” the treatment is needed. Since individual moths are almost impossible to detect, the visual observations of injuries caused by previous generations are only the “other best option.”
If the handling of the earlier generation(s) was successful, there is a chance no control or only a very limited pest management program will be necessary. If insecticides are needed, products from IRAC Group 28 (ryanodine receptor modulators) such Altacor®, Exirel®, Minecto Pro®, and Besiege® or a single product (Delegate®) from the IRAC Group 5 (nicotinic acetylcholine receptor agonists; spinosyns) are highly active against CM, OFM, TABM, and OBLR larvae. For the highest efficacy, insecticides used for the management of CM and OFM need to be applied before larvae enter the fruit, which usually happens in less than 24 hours after the egg hatch. After larvae are already inside the fruit, no product can manage them.
In orchards using an effective CM or OFM mating disruption treatment, only leafroller control may be necessary, and products such as Intrepid ® (ecdysone receptor agonist, IRAC Group 18) will provide effective leafroller control. To prevent the development of insecticide resistance, it very important to rotate various modes of action of insecticides when controlling successive generations of the pest. For example, if Altacor was used earlier this season, no products from IRAC Group 28 should be used again this season. The potential alternatives should be products from another IRAC group(s). In orchards managed with products approved for organic production, applications of codling moth granulosis virus (Madex® HP or Cyd-X®) should start right at the beginning of the moth flight and be repeated at intervals no longer than seven days. Madex HP should also provide good control of Oriental fruit moth larvae. Leafrollers can also be managed by applications of products containing Bacillus thuringiensis (Dipel®) or spinosyns (Entrust®).
Photo 2. Peach fruit injured by Oriental fruit moth larvae. Photo: G. Krawczyk, Penn State
Photo 3. Tufted apple bud moth larvae in leaf shelter. Photo: G. Krawczyk, Penn State
Photo 4. Feeding on mature fruit by obliquebanded leafroller larvae. Photo: G. Krawczyk, Penn State
Brown marmorated stink bug and Spotted lanternfly
It is time to again to think seriously about monitoring brown marmorated stink bug. During late summer and fall, high numbers of BMSB adults are capable of moving into orchards from the surrounding vegetation such as woods or field crops. The migrating BMSB adults and nymphs developing from eggs deposited in orchards potentially can cause significant damage to fruit until the harvest. The on-site monitoring remains the best indicator if treatments 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.
Detection of BMSB nymphs (Photos 6A, 6B) in monitoring traps placed in orchard warrants the need for an application of an effective insecticide. With all “traditional pests” also potentially present in the orchard, it is critical that the choice of insecticides directed against other pests would take into consideration the possible control of BMSB population present in orchards at the time of application. During the 2018 season the Environmental Protection Agency granted again the Section 18 Special Emergency Registration for the use in Pennsylvania of two additional active ingredients: pyrethroid bifenthrin (IRAC Group 3A) sold as Brigade ® WSB (FMC Corporation) and Bifenture ®10DF and EC (United Phosphorus Inc.), and a neonicotinoid insecticide dinotefuran (IRAC Group 4A) sold as Venom® (Valent USA LLC.0 or Scorpion® (Gowan). The Section 18 registrations for both active ingredients expire on October 15, 2018.
The complete list of BMSB effective insecticide options includes products with only few distinctive modes of action: pyrethroids (IRAC Group 3A) such as Bifenture® EC and 10DF and Brigade® WSB (the same AI, bifenthrin), Danitol® (fenpropathrin), and Warrior® (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).
With at least 12 more weeks of possible BMSB activity to go (until mid-October on late-maturing apple varieties), it is essential for growers to plan ahead with the choice of products utilized against BMSB. Preserve the most effective options, especially with the shortest Pre-Harvest Intervals (PHI), for applications when the pressure from this pest increases in the latter part of this season, usually in September and early October.
While looking for the brown marmorated stink bug, please also pay attention to the newest invasive pest, the spotted lanternfly. Discovered in 2014 in south-east Pennsylvania, during the fall of 2017 season this pest was observed in high numbers in fruit orchards and vineyards.
For more information about SLF, please visit the Penn State Extension spotted lanternfly web resources.
Spotted lanternfly is a quarantine insect in the 13 southeastern counties in Pennsylvania, and anyone finding this insect outside of the quarantine area is asked to notify the Pennsylvania Department of Agriculture.
If SLF management is needed in fruit orchards, insecticides active against BMSB should also be useful for the control of SLF nymphs and adults.
Photo 5A. Spotted lanternfly nymphs on a tree of heaven. (Ailanthus sp.) Photo: Jenna Ulrich, Penn State
Photo 5B. Spotted lanternfly adults on an apple tree. Photo: G. Krawczyk, Penn State
Photo 6A. Brown marmorated stink bug nymphs and adults on soybean. Photo: G. Krawczyk, Penn State
Photo 6B. 2nd instar brown marmorated stink bug nymphs next to BMSB egg mass. Photo: T. Hass, Penn State
Woolly apple aphid
Woolly apple aphid (WAA) colonies are being observed in some orchards across the region. Most WAA colonies are starting around wounds or leaf petioles and continue to increase and move as the season progress. Tiny parasitic wasp Aphelinus mali and syrphid flies (Heringia calcarata and Eupeodes americana) predatory larvae are very effective in natural control of WAA colonies. Unfortunately, the beneficial insects are also susceptible to many synthetic pesticides and the natural control of WAA can easily be disrupted by the use of pyrethroid and neonicotinoid insecticides applied to manage other pests such brown marmorated stink bug or leafhoppers. If insecticidal control is needed for WAA, control the most effective products are Diazinon® (various formulations) and Movento®. Both of these products, if applied at the correct timing, should also help with the management of second summer generation of San Jose scale crawlers.
Photo 7. An aerial colony of woolly apple aphid on apple branch Photo: G. Krawczyk, Penn State
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 pest management recommendations, refer to the Insect and Mite Control Toolbox.
Seasonal Activity of Fruit Pests
2018 season weekly average captures of adult moths in pheromone traps located at the Penn State Fruit Research and Extension Center, Biglerville, PA (Adams County)
Accumulated degree-days base 43°F from Jan 01 for each reported year (courtesy of SkyBit, Inc.)