Lessons from offhsore in BMSB management
While Brown Marmorated Stink Bug (BMSB) is not established in New Zealand, our focus is on preventing it arriving here and acting swiftly to eradicate it should it be detected. However, KVH and Zespri are also preparing for how the pest would be managed within kiwifruit orchards if it were to establish here.
As part of these preparedness efforts Zespri recently organised a global BMSB teleconference to hear about impacts, management approaches and research efforts across global production areas. Updates were provided from Italy, China, France, USA, and a research update from New Zealand.
In Italy, BMSB has been present since 2012 but is so far restricted to northern areas. Damage to horticulture has been reported since 2015 with peak damage to kiwifruit production being July and August (leading up to harvest). Bugs are typically found in the morning, at the top of vines, near orchard borders. Growers are setting up nets on the borders of their orchards, using hail nets above and on the sides. This type of netting is considered cheap and relatively effective in reducing impacts to crops, but not eliminating damage altogether as the smaller BMSB nymphs (but not adults) are still able to enter through the mesh. Some growers are experimenting with smaller 2.2mm mesh to provide greater exclusion at keeping the bugs out. Studies are underway in Italy to better understand the use of trap crops, and whether a certain combination of sacrificial crops grown in close proximity to kiwifruit can provide a window of protection until kiwifruit are harvested.
In China, BMSB populations are at their peak just before harvest, as has been noted in Italy. Other research projects underway here have confirmed BMSB has an impact on storage quality as fruit softens more quickly, and orchards with the worst damage need to remove fruit from coolstore earlier as storage life is shortened.
In France, BMSB has only recently been detected in 2018, but already impacts to horticulture are being observed. The use of hail netting around French orchards is now considered best practice, with insect proof netting even better if possible. Researchers have compared Rescue (reusable hanging lure) and Fisher (pyramid shaped lure that sits on the ground) pheromone traps and found that the Rescue type seems to do better with catches peaking in August - in line with general population peak - for both adults and juveniles.
In the USA, a gold kiwifruit grower based in Alabama estimated that fruit loss attributed to BMSB may have been around 50%. Again, numbers of the bug peaked just before harvest (August and September). Traps have been used and caught up to 100 bugs a week. The grower has experimented with trap crops (sorghum, sunflower, corn, soybean, cotton) as well as gardens around the crops. All have shown some potential, but none have successfully controlled BMSB numbers. Chemical trials of products permitted for use on kiwifruit have demonstrated a limited effect.
KVH and Zespri will continue to get updates from across global production areas and share information with growers so that as an industry, we can implement practices that will reduce impacts in the event of a BMSB population being found in New Zealand.
BMSB is the current focus of many research projects within our Kiwifruit Biosecurity Research Portfolio and amongst aligned research providers. At a national level under the BMSB Council (with the Ministry for Primary Industries (MPI)) this is mostly focused on improving preparedness for a response to increase the likelihood of eradicating this pest, or reducing numbers to a level that will reduce subsequent impacts to New Zealand.