The Ministry for Primary Industries (MPI) has initiated a biosecurity response following confirmation of a single, unmated female Yellow Spotted Stink Bug (YSSB) found last week in Temuka, South Canterbury.
KVH has notified ‘KiwiNet’ – a group of industry people selected by their organisations to form the kiwifruit industry capability network for biosecurity readiness and response.
MPI are asking the South Canterbury community to help by looking out for any further YSSB bugs and to call the Exotic Pest and Disease Hotline 0800 80 99 66 to report any suspect sightings.
MPI occasionally intercept live and dead specimens of YSSB. To date, these have all been single individual bugs - not breeding populations.
MPI investigators have carried out surveillance at the property and surrounding area where the bug was found to confirm there are no more present. Nearby transitional facilities have also been inspected and no further finds have been made.
Limited information is available on the potential impacts and host range of this species. However, the host range could include several species of economic importance to New Zealand. At this stage it is unknown whether kiwifruit would be significantly impacted if the YSSB was to establish in New Zealand.
YSSB isn’t considered as potentially damaging as Brown Marmorated Stink Bug (BMSB). Unlike BMSB, YSSB is not known to be an urban nuisance pest anywhere in the world.
YSSB is typically a hitchhiker pest, which means, for example, that they could arrive here from overseas in containers or used machinery and vehicles.
This is the first biosecurity response carried out under the Government Industry Agreement on biosecurity readiness and response (GIA). Kiwifruit Vine Health (KVH) is working in partnership with MPI and Pipfruit NZ.
For more details and a description, please see the Yellow Spotted Stink Bug fact sheet here.
Key Industries (manufacturers of KeyStrepto™) have advised KeyStrepto™ is now in stock. However, growers are reminded it cannot be used on kiwifruit vines within one week of the first flower appearing (male or female), and can only be used in the north island.
The KeyStrepto User Guide details the conditions of use.
Protection of wounds following hail is important to minimise Psa-V infection, particularly on blocks where Psa-V risk is high. With recent hail damage and the possibility of further hail bands sweeping across the country growers are reminded of their options.
Alternating sprayer travel up rows in alternate spray rounds will maximise coverage of hail wound sites. Do not spray blocks if bees are actively foraging.
Zespri has further information for growers with orchards affected by recent hail events, including information about insurance cover—click here to view on the Zespri Canopy.
This week KVH met with Gisborne growers to see first-hand the level of Psa-V progression on positive orchards within the region.
Gisborne did not suffer severe winter or spring frosts this year. However, spring growing conditions have been difficult with significantly higher than normal rainfall for both August (155% higher than 2013) and September (185% higher than 2013). Cooler temperatures and long periods of wet weather, particularly toward the end of September, have led to higher levels of cane die-back and leaf spot symptoms on already infected orchards.
The level of symptoms seen on Gold variety orchards was generally low. Males and vines in tougher growing conditions, such as those suffering from water-logging, had more die-back and leaf-spot. However, monitoring and cut-out rounds are continuing to minimise infection levels within the orchards. Removed material continues to be bagged and buried, or burnt.
Growers with vulnerable Gold varieties have clear plans for the removal of these blocks. With pollination now complete, the removal of the higher-risk male varieties from Hort16A blocks in their final production year is recognised as a means of reducing Psa-V risk for these orchards. Early removal also provides the opportunity for the earlier establishment of males suitable for Gold3.
Gold3 is performing well. Growers commented that signs of Psa-V are limited to a few canes with dieback, and on individual blocks some minor infection has been seen in a few M91 males. Again, male pruning provides an opportunity to remove this infection and to restructure vines to support good penetration of protective sprays for the balance of the season.
Some leaf spotting and sepal staining has appeared in the last three weeks in Hayward varieties on cold, wet sites and the impact of this is still to be seen.
The progression of bounty rootstock is being observed with interest. To date, some failed plants have been attributed to Psa-V infection. Overall however, this rootstock is showing promise in blocks with more difficult soil conditions where this new rootstock is being established.
Overall, as weather conditions start to improve, the rate of symptom progression is expected to slow across the region. However, robust protective spray programmes are still recommended to put vines in the best position as Hayward varieties move through to the higher-risk flowering period.
The Gisborne region now has 19 Psa-V positive KPINS. This represents 29% of orchards and 44% of kiwifruit hectares. Of these KPINS seven new finds were reported since 1 August 2014.
To minimise biosecurity risks across the supply chain, and to assist nurseries in meeting the Kiwifruit Plant Certification Scheme Core Standard, KVH has produced a series of factsheets on biosecurity best practice for kiwifruit nurseries. An independent nursery expert has assisted KVH in developing these factsheets which are aligned with key components of the Core Standard.
These factsheets will be added to over time and currently include:
KVH has amended its best practice guidelines for orchard hygiene to include a more practical approach in Recovery regions where infection is widespread.
The revised guidelines also recognise the lower risk of some vehicle movements onto orchards, such as harvest machinery, quad bikes used for maturity clearance, and fertiliser spreaders. These should be checked and have all visible plant material removed. However they no longer require sanitising between orchards in the same Recovery region. Higher-risk vehicles which come into direct contact with kiwifruit plant material (such as mulchers, root pruners etc) should continue to be cleaned and sanitised between orchards.
All vehicles should be cleaned and sanitised between Recovery regions. The requirements for Containment and Exclusion regions remain unaltered.
Growers in all regions are required to carry out a round of mandatory monitoring in November. Growers in Exclusion and Containment regions must submit their results to KVH by 10 December using the simple online tool.
Growers in Recovery regions must record their results and file with their GAP records and are also encouraged to submit them to KVH by 10 December.
Mandatory monitoring is an important tool for the industry, as it allows KVH to report a more accurate picture of Psa-V progression around New Zealand. Additionally, early detection and intervention is the most effective method to control and minimise the impact of Psa-V.