Pressure from Stink Bugs Continues in Apple Orchards
Posted: August 26, 2011
Fresh injury on apple fruits caused by feeding of brown marmorated stink bug. Photo: Greg Krawczyk
Based on our experiences from last season, we expect that stink bug feeding will continue at least until mid-October this year. BMSB adults will continue feeding as long as weather permits or until they begin moving towards their overwintering sites. This late season feeding can be very intensive, as adult stink bugs are trying to accumulate enough resources to survive the winter. While the BMSB adults are in their overwintering shelters, they do not feed so all resources need to be gathered before moving into their shelters.
Monitoring for the brown marmorated stink bug still remains an area that requires a lot of attention. While the currently used trapping systems started capturing both adults and nymphs over the past few weeks, there are still a lot of gaps in our understanding on how to interpret these findings. The aggregation pheromone currently utilized in traps is not species-specific and it appears that it can attract higher numbers of individuals than the traps are capable of capturing. But if detection of the stink bug is the goal of the monitoring activities, then those traps should be able to serve this purpose.
Fortunately, not every orchard will experience the same high pressure from the brown marmorated stink bug. Based on our current observations (through late August), the highest numbers of brown marmorated stink bugs were observed on the edges of orchards bordering with woods or various agronomic crops. We have seen hundreds if not thousands of BMSB in some soybean and corn fields, although not every soybean/corn field has high populations. But definitive, cautious scouting and monitoring of the vegetation surrounding an orchard 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 what 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 harvest.
In order to manage possible infestations, a careful monitoring program needs to be employed. If injured fruit or stink bugs are detected, then the decision will have to be made about the best approach to manage the problem. Insecticides still remain the most effective BMSB management tool, but none of them will protect fruit from some level of 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 newcomers from at least initially probing the fruit. Remember - each probing equals an injury. Most of the effective insecticides provide only a few days of residual protection. The results of our currently conducted 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).
The following list includes insecticides with significant 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 earlier laboratory bioassay results conducted last winter and during this season.
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%.
Clothianidin (IRAC Group 4A)(Belay) – 7 days PHI on apples and pears; 21 days 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, Special Section 18 emergency registration until Oct 15, 2011) – 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 – (thiametoxam mix with lambda-cyhalothrin))- 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%.
Always read the label before applying any pesticide.
SEASONAL ACTIVITY OF FRUIT PESTS
2011 season - weekly captures of adult moths in pheromone traps located at Penn State FREC Biglerville, PA (Adams County):
Species 7/07 7/14 7/21 7/28 8/04 8/11 8/18 8/25
RBLR 11 6 1 16 19 22 31 24
STLM 65 161 137 52 27 39 123 159
OFM 6 3 2 2 32 22 27 30
CM 15 43 26 20 25 45 20 19
TABM 1 3 4 4 4 2 2 2
OBLR 0 1 1 2 1 3 0 0
Key to acronyms: RBLR - redbanded leafroller; STLM - spotted tentiform leafminer; OFM - Oriental fruit moth; CM – codling moth; TABM – tufted apple bud moth; OBLR – obliquebanded leafroller.
DEGREE-DAY TABLE: 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 (Sep 01) mentioned in the table are based on the weather forecast.
Site/Date 7/28 8/04 8/11 8/18 8/25 9/01
Biglerville, 2011 3029 3281 3512 3716 3919 4122
Biglerville, 2010 3145 3366 3612 3833 4043 4248
Biglerville, 2009 2637 2858 3078 3310 3541 3743
Biglerville, 2008 2727 2955 3150 3335 3529 3710
Biglerville, 2007 2732 2974 3218 3433 3603 3819
Biglerville, 2006 2771 3043 3260 3458 3676 3880
Biglerville, 2005 2676 2898 3130 3370 3571 3777
Rock Spring, 2011 2603 2833 3043 3227 3407 3577
Rock Spring, 2010 2742 2941 3156 3356 3542 3710
Rock Spring, 2009 2218 2411 2598 2814 3016 3184
Rock Spring, 2008 2324 2528 2696 2859 3034 3193
Rock Spring, 2007 2339 2596 2818 3011 3168 3360
Rock Spring, 2006 2391 2641 2837 3012 3203 3376
Rock Spring, 2005 2331 2551 2766 2986 3167 3347
