The cancellation of trans-Tasman international flights in and out of Rotorua Airport means there is one less biosecurity risk pathway into New Zealand.
Since the trans-Tasman flights started in 2009, Rotorua Airport has been a potential entry pathway for biosecurity risks into New Zealand. Of particular concern was the risk of importing Queensland Fruit Fly from Australia directly into the Bay of Plenty.
Last year KVH completed a preliminary review of border interventions at Rotorua Airport to ensure potential biosecurity risks to the kiwifruit industry were being managed appropriately. While KVH was satisfied with the level of biosecurity intervention on this pathway, the cancellation of the flights eliminates this risk altogether and enables MPI resources to be applied to managing other pathways.
Rotorua Airport will cancel its international air service from the end of April 2015.
Chilean growers have been dealt another significant blow after frosts last week devastated crops for the second year in a row. One large producer estimates between 80-100% crop loss on some kiwifruit orchards.
The frosts, which were “completely unexpected” came roughly one year after severe frost wreaked havoc on almost the entire Chilean agricultural industry last year. Many growers did not have their frost protection systems turned on as the weather had been so mild.
This week KVH visited twelve orchards in the Whanganui region and also held a meeting with local growers to discuss best practice Psa-V management strategies and to provide latest research information.
All growers in the region had good monitoring programmes in place. Results from these show some spring progression within previously affected orchards. Levels of infected male vines remain below 10 percent with cane dieback and exudate being the symptoms observed. Minimal numbers of female vines are showing any infection.
Severe spring wind, and for some, recent hail events, have provided challenging growing conditions and proactive spray programmes, cut out of infection as it is found and good orchard hygiene procedures is likely to have minimised infection spread to date.
No leaf spot was evident. However, some bud browning was seen on one Psa-V positive site.
Shelter and adequate pollination are seen as challenges in this region. Notch-grafting of older male varieties has begun. Successful results from December 2013-grafted males, has resulted in growth which will contribute to pollination this year.
This region previously had two unmanaged sites recorded, and each of these sites were visited. One of these blocks has now been removed and the other has been returned to management.
Using products at lower than the recommended label rates can increase the risk of resistance developing, and has been implicated as a factor in cases of resistance to disease in other crops.
Given the limited control options available, it is important the kiwifruit industry use the tools that are available appropriately. This will maximise the useful life of the products. To reduce the risk of resistance, it is very important that the label instructions, including label rates are followed.
On-going use of products outside label recommendations risks ACVM reviewing copper label approvals.
The use of KeyStrepto™ at less than label rates is illegal, and must not occur in any circumstances.
Growers who are concentrate spraying need to adjust product rates to ensure correct rates are applied.
Low levels of leaf spotting within some orchards in the Bay of Plenty region have been reported over the last week. Sepal browning is being reported for some blocks historically vulnerable to bud infection. Leaf spot symptoms are traditionally seen this time of year—often appearing after periods of wet weather and particularly if these are also associated with wind and cold conditions.
Research has shown that a good protective spray programme helps minimise leaf spot symptoms, reducing inoculum build-up within orchards. Maintain copper cover, and in high-risk situations the use of KeyStrepto™, is highly recommended at this time to avoid build-up of orchard inoculum levels. Actigard™ provides further support by eliciting the vine’s defence system through this critical pre-flowering period.
Growers intending to trunk girdle as an additional tool against flower bud and flower infection are recommended to leave some un-girdled vines, to allow measurement of the value of this tool on their individual site. Click here for Zespri’s methodology on the Canopy.
Copper protectant products Tri-Base Blue® and Champ™ DP have been removed from KVH’s recommended product list (below) as their use period from post-harvest to leaf-fall and then through dormancy has ended.
Pollination is the next key activity on the kiwifruit calendar and movement controls apply for both pollen and beehives.
All pollen providers and distributors of pollen are required to register with KVH and growers should only be sourcing pollen from these registered providers—click here for the registered lists.
For more information about pollination movement controls and/or to register with KVH please visit www.kvh.org.nz/beekeepers.
Last week KVH completed a round of monitoring in the North-West Auckland region. The region is currently classified as an Exclusion region with a Controlled Area in place.
Seven orchards were inspected and samples were taken from three orchards. All tests were confirmed ‘Not Detected’.
There is one positive orchard in the region—confirmed in November 2013. The Hort16A on this orchard was removed immediately following the positive test and stump-grafted to Gold3.There are no signs of further Psa-V infection on this orchard.
North-West Auckland growers are maintaining good protectant programmes hygiene. Only one Hort16A orchard remains and this has been notch-grafted to Gold3.
Key Industries, the New Zealand supplier of KeyStrepto™ have advised there is currently no stock of KeyStrepto™ available for kiwifruit growers due to demand far exceeding supply. Zespri, KVH and retailers have been working with Key Industries to secure more supply as soon as possible. The shortage is due to offshore production constraints, not transportation.
As a result, it appears unlikely sufficient KeyStrepto™ supplies will be available to the kiwifruit industry before flowering this season.
Growers should re-consider their Psa-V control plan and ensure alternative control products are used.
Alternative Psa-V control products allowed pre-flowering include:
Growers should not consider using Kasumin® as a replacement for KeyStrepto™. Kasumin® has been removed from the Zespri Crop Protection Programme for the 2015 season while further research is done to confirm the most effective use pattern. This work is expected to confirm the optimal pre-flowering withholding period for Kasumin® and the number of applications allowed in the pre-flowering period.
Symptoms of female flower bud infection are being seen on some Hayward orchards which suffered bud-rot in previous years. Brown discolouration of sepals and fine droplets of moisture on the surface of the buds are likely indications of Psa-V presence. These symptoms may not necessarily have obvious leaf spot associated with them. Within the same blocks, presence of red exudate on terminal buds, collapsed shoots and infected buds on the ends of female canes are other signs of Psa-V.
Growers are recommended to preferentially remove infected buds in pre-flower thinning rounds, cut back infected canes, continue with a protective spray programme and consider a pre-flowering girdle to help with bud-rot control.
Recommended timing for a pre-flower girdling for bud-rot control is 16-30 days pre-flowering so growers should plan for this now.
All growers are urged to measure impacts of this treatment on their site. Leave some control vines amongst girdled areas or alternatively, girdle only a few vines within high-risk blocks and measure flower-to-fruit retention for treated and control vines. A methodology to assist growers has been developed by the Zespri OPC team.
Tool hygiene is essential when pruning and/or girdling within these blocks.
Last week KVH followed up on two reports of unpruned orchards within the Te Puke region. Removal of vines was nearing completion on one property and the lease status of the second is being followed up.
Rules within the NPMP require completion of winter pruning (cutting and tying down of vines) by 1 October each year. Growers or concerned parties should contact KVH for follow-up of suspected unpruned or unmanaged blocks. NPMP rules are in place to reduce the risk of blocks harbouring Psa-V and providing risk to neighbouring orchards.
Growers should monitor their male vines for Psa-V infection and work to remove or reduce cankers where they occur. Cankers are Psa-V inoculum sources and create infection risk for male and female flower-buds. Infected male flowers can result in insufficient male pollen supply within the orchard and severely impact on orchard productivity. Where male plants are showing infection, assess pollen needs and make arrangements with your pollen provider now. Indications are that pollen availability is low this season.