Nymphs are rapidly becoming adults and have been found increasing in our regional trap captures. Traps continue to exceed threshold in Highland, Marlboro and New Paltz in Ulster County, Fishkill in Dutchess and Campbell Hall in Orange County traps over the past week. All life stages along 8 commercial blocks in mid-Hudson Valley orchard sites have been observed this past week. Movement to apple foliage and fruit continues.
Over the past 22 days we have had 0.83″ of rain. Dry weather causes host plants of stink bug to dry out, reducing available moisture for these insects. Tree fruit then become more attractive, especially along the orchard edge where native and the invasive brown marmorated stink bug can gain easy access. Keeping an eye on both traps and fruit is critical this time of year.
Trap numbers of stink bug in combination with scouting, should precede management during BMSB population build-up. Review labels for pre-harvest intervals (PHI) when choosing materials as the most effective materials have 14 DTH constraints.
When thresholds are exceeded (10 adults / trap weekly) or stink bug become visible along the orchard edge, border row applications should begin. These should then be followed by alternate row, then whole orchard applications as movement of native and BMSB populations begin to migrate into orchards. As stink bug are orchard edge opportunists, the majority of the injury to fruit will occur along the 30′ perimeter edge.
We have found that waiting for fruit injury to ‘appear’ after stink bug are observed in traps and on trees prior to management will allow for economic injury to occur. In most years the expression of feeding injury will take from 10 to 14 days for darkened depressions and corking of feeding sites to manifest. To reduce injury, management is required upon the insects arrival into the orchard. As most insecticides for other insects are relatively ineffective against the stink bug insect complex, it is critical to make decisions on selection of the most effective insecticides available for this pest.
The brown marmorated and native green stink bug are arboreal insects, residing in woodland habitat. However, when populations continue to rise through July into August, increasing numbers of adults and nymphs can be observed on tree fruit. his has occurred over the past two weeks. Increasing presence of the insects in trees will result in injury in peach, pear and apple rows bordering woodlands and hedgerows. Nymphs ranging from 2nd to 5th instar of both species have been observed feeding on fruit along the orchard perimeter this week.
This newly developing partial second generation will significantly increase BMSB population in woodlands. As host quality from the arborial woodland habitat declines, increasing migration to tree fruit is very likely through the end of August on through to the end of October. Increased scouting should be based on recent and upcoming Tedders trap captures. This will be especially important if weather turns dry with irrigated tree fruit becoming a favored host of BMSB as adults begin to feed more intensively as they prepare for their overwintering phase.
Monitoring: Remember that trap captures combined with scouting for the various life stages of the insect along the orchard perimeter rows should be the basis for insecticide applications. Unlike most other pests, we should not be using IPM thresholds based on stink bug feeding that results in fruit damage. As expression of the injury occurs 7-10 days or longer after feeding, you would have missed your opportunity to reduced injury if you postpone preventative applications while waiting on injury that has already occurred to become visible.
Use a conservative presence and trap threshold on through harvest. Finding a single BMSB or green stink bug in the tree canopy within 100′ of scouted perimeter row would be considered a conservative threshold. Driving along the orchard will likely spook the insects. You’ll need to stealth your way quietly around the orchard…its good exercise in the early evening or morning. Green stink bug tend to remain low while BMSB tend to move to the tops of the trees to feed.
Management: When selecting insecticides for border row, alternate row and whole orchard applications you should consider constraints on your markets. If weather turns to drought, then longer residue based on the active ingredient minimum residue level (MRL) could become an issue, especially in EU markets and Israel. Review your options carefully with regards to harvest dates, PHI’s, re-application intervals and seasonal A.I. volume.
When BMSB populations dramatically increase during late season, migration into orchards can be dramatic. BMSB have been known to funnel down to the last variety standing (such as the high value Pink Lady). In which case applications in late October may be warranted!!
Applications of insecticides selected for whole orchard applications should also have strong efficacy for apple maggot, obliquebanded leafroller and 3rd generation codling moth if CM infestations from 1st or 2nd generation are active, which may also require management.
One of the most effective tools for use to manage BMSB is the active ingredient bifenthrin in a number of formulations.
Bifenthrin has a 12 hr. re-entry interval, 14 day pre-harvest interval and a 30 day re-application interval.
We received notice that the EPA has approved the Section 18 application for bifenthrin for use against the brown marmorated stink bug for 2019. Links below provide access to PDF copies of the Section 18 labels for materials containing the A.I. bifenthrin.
Labels should be made available to the applicator during bifenthrin applications. These can be printed or available as digital files such as PDF’s on tablets or smart phones. The exemption is valid through October 15th 2019 as a “Section 18 EXEMPTION under FIFRA, FOR DISTRIBUTION AND USE ONLY IN Columbia, Dutchess, Orange, Ulster, Monroe, Orleans, Wayne and Niagara Counties this year. Use in any other counties is prohibited in NEW YORK STATE”.
For all Bifenthrin products, the Section 18 permit can be used in apple, peach and nectarine. Do not apply more than a total of 0.50 lbs ai/acre per season. Apply as necessary to maintain control using a minimum of 30‐day spray intervals, 14-day pre-harvest interval and a 12 hour REI. Bifenthrin labels include: