Sustainable practices for the management of the invasive brown marmorated stink bug, Halyomorpha halys (Stal), on vegetables
Several different sustainable approaches were investigated on farms for managing brown marmorated stink bug (BMSB) on peppers. In one experiment trap crop border rows of sweet corn and sunflowers had more adult BMSB than control plots of peppers, but there was no significant difference in the numbers of nymphs on peppers or on the % of pepper fruit damaged by BMSB, which averaged about 30-40% regardless of treatment. On vegetables, 208 BMSB eggs were found with 82 eggs (39.4%) parasitized. A pyrethroid-incorporated polyethylene mosquito netting was explored as a control tool for protecting vegetables against BMSB. Fresh netting and netting that had aged in the field for 2 months were toxic to BMSB, killing nymphs and adults after constant exposure to the screen for 2 hrs.
- Objective 1: Evaluate the potential of a trap crop of sweet corn and sunflower trap crops to reduce the numbers of BMSB in the primary crop, bell peppers.
During the first year of the study we will determine if stink bug populations can be maintained below economically damaging levels in the primary crop through implementation of a trap crop.
Objective 2. Evaluate if a trap cropping system increases egg parasitisim of the BMSB.
Stink bug egg masses will be sampled weekly and assessed for natural egg parasitism.
Objective 3. Evaluating the potential of new technology to reduce stink bug damage on high value vegetables.
Specialized long-lasting mosquito screening will be obtained from Vestergaard-Frandsen Inc. (Sweden) and assessed for efficacy against BMSB.
Experimental plots were planted at 3 locations in southwest Virginia to determine if stink bug populations can be maintained below economically damaging levels in the primary crop through implementation of a trap crop. The plots were 50 ft by 4 rows. The first plot did not have a trap crop and was planted as 4 rows of bell peppers only. The next two blocks implemented a trap crop strategy: one with sunflowers and one with sweet corn. For these treatments, the middle 2 rows of each block consisted of bell peppers while the outer one row on each side was comprised of the trap crop.
Twenty-five peppers per row per plot (50 total) were assessed for stink bug damage (Table 1) 3 to 4 times during the season. Stink bugs were sampled weekly by counting total stink bugs on 10 plants per row (20 plants/plot) at 9 time periods during the season (Table 2).
No statistical difference was discerned in either stink bug number over the season, or stink bug damaged pepper.
Table 1. % stink bug damaged pepper (n= 50 fruit).
Pepper w/ Pepper w/ Pepper
Date Location Sunflower Sweetcorn control
6-Aug Kentland 1 40 42 28
17-Aug Kentland 1 64 44 40
10-Sep Kentland 1 34 14 30
28-Aug Kentland 1 28 28 26
Mean % damaged peppers 41.5 32 31
6-Aug Kentland 2 18 22 28
17-Aug Kentland 2 38 44 28
10-Sep Kentland 2 30 48 44
28-Aug Kentland 2 32 42 40
Mean % damaged pepper 29.5 39 35
2-Aug Glenvar 36 46 56
16-Aug Glenvar 50 22 38
29-Aug Glenvar 22 40 34
Mean % damaged pepper 36.0 36.0 42.7
Table 2. Mean # SB for 9 sampling periods on 20 plants (n = 3 locations).
Sunflower/Pepper Sweet Corn/Pepper Pepper
Life Stage Sunflower Pepper SweetCorn Pepper Internal Border
Adults 7.3±4.8 0.3±0.3 6.3±0.9 2.3±0.7 0.7±0.7 1.3±0.3
Nymphs 13±5.7 15.3±12.5 9.0±7.0 9.7±.8 11.0±11.0 17.3±11.9
Egg Masses 0.0±0.0 0.7±0.7 0.3±0.3 1.0±0.0 1.0±0.6 0.3 ± 0.3
PARASITISM OF EGG MASSES
Three-minute visual surveys were conducted weekly from April/May through September on wild hosts as well as agricultural commodities in southwest Virginia (Montgomery and Roanoke counties) during the 2011 and 2012 growing seasons. All stink bug species and life stages were counted and recorded.
Only data from natural-occurring BMSB eggs were collected. During the survey, all egg masses were collected and number of eggs as well as hatched, unhatched, or parasitized were recorded. Unhatched eggs were brought back to the laboratory and maintained in a growth chamber at 60-80% RH, 27 ± 2°C, and a photoperiod of 16:8 h (L:D) until hatch. Parasitoids were collected and stored in 70% alcohol. Species identification of any emerged parasitoids has not been done at this time.
Egg parasitism numbers were recorded for all egg masses (hatched and unhatched eggs) for 2011 and 2012. In 2011, 2449 eggs were found on trees with 155 (6.3%) parasitized and successful emergence of 120 parasitoids. On vegetables, 226 eggs were discovered, 48 eggs (21.2%) were parasitized, and 11 parasitoids successfully emerged. In 2012, 2964 eggs were found on trees with 122 (4.1%) eggs parasitized and successful emergence of 38 parasitoids. On vegetables, 208 eggs were found with 82 eggs (39.4%) parasitized and 0 parasitoids successfully emerging.
Identified Parasitoid species included:
Trissolcus euschisti, Telenomus persimilis, Anastatus reduvii, Trissolcus thyantae, Anastatus sp., Trissolcus edessae, Telenomus podisi, Anastatus sp.
Impacts and Contributions/Outcomes
Additional research is needed on each of the sustainable approaches investigated. Trap cropping with sunflowers or sweet corn was not effective. This approach will need refinement, particularly with methods of removing adult BMSB when they aggregate on the trap plants. BMSB egg parasitism averaged around 30% in vegetable plots, which is encouraging for the potential of natural control of this insect increasing. Pyrethroid-incorporated mosquito netting is efficacious against BMSB. Methods of using this screening feasibly and economically in sustainable vegetable production should be explored.
Department of Entomology
Blacksburg, VA 24061
Office Phone: 5402316129