Farmers wait on velvetleaf’s impact
Waikato maize growers will soon know how badly the region is affected by velvetleaf because the invasive weed is expected to start appearing in paddocks in October.
Velvetleaf has been discovered on 29 Waikato farms - predominantly in the Te ArohaWaihou area - since it was found in late April this year. It is suspected to have spread to another 70 farms in the region. These farms would be closely monitored and a 12-person industry-wide committee was being established to help spearhead velvetleaf management this summer, Waikato Federated Farmers arable chairman John Hodge said.
It would be very interesting to see the weed’s effect this spring. ’’Everybody is holding their breath to see how bad it is.’’
Velvetleaf’s potential impact was outlined at a meeting attended by about 30 farmers at Elstow, near Te Aroha. Waikato Regional Council pest plants team leader Darion Embling said ignoring the risks could come at a huge cost. In the best-case scenario, the region faced a 30 per cent loss of income for the arable industry a decade from now.
’’The arable industry in New Zealand is worth $1.5 billion so you are looking at $500 million per year this country could lose.’’
Dealing with the weed cost the Waikato Regional Council more than $200,000 last year.
He said Waikato’s situation was unique because the weed was found in maize as well as fodderbeet. Elsewhere, velvetleaf had been found only in fodderbeet.
Key to containing it in summer would be management plans specific to the farms where fodderbeet was found.
Its discovery in maize meant it could potentially be spread to other farms through sales of maize grain and silage for cattle, chickens, goats and pigs.
Velvetleaf seeds could become mixed in the feed, eaten and spread onto the farm in dung.
A successful response required a collective effort from farmers, the wider industry, and local and central government. The place to break the cycle was at the beginning on the maize crop, Embling said.
That meant ramping up farm biosecurity by regularly checking crops for unusual weeds and establishing wash-down stations to clean machinery. ’’Treat the property like it’s a border, like it’s an island.’’
While maintaining machine hygiene would be time-consuming, the alternative of velvetleaf on the farm was far worse.
‘‘You have got to weigh up who is going to lose if someone gets this plant. You have got a lot to lose if it becomes established on your property,’’ Embling said.
He advised farmers moving stock on and off farms to quarantine the animals for at least 24 hours before shifting them onto a paddock.
‘‘Graze the velvetleaf last if they are staying on the property or if the stock are going to leave, graze the property first.’’
Farmers should also record movements of animals in paddocks where velvetleaf was present and, where practical, fence off areas known to have the weed. Velvetleaf seeds lived for 50-60 years and were extremely hard to find in tall crops like maize.
He advised maize growers to consider planting shorter crops on paddocks where velvetleaf was suspected to make it easier to see the weed.
‘‘If you can, put your paddock back into pasture and then if you have velvetleaf it will pop up and you will find it and you can manage it then.’’
However, it was unrealistic to expect commercial maize growers to make large-scale changes to a different crop because it would mean a loss in income, Hodge said.
If pasture was grown, it would mean finding a dairy farmer whose herd could graze it or cutting it up and selling it as grass silage. ’’There’s only a limited market for it because dairy farmers have got no money.’’
As of June this year, maize grain plantings were 36 per cent down nationwide and the threat of velvetleaf would only fuel that further.
The presence of velvetleaf would be a conversation topic among maize growers negotiating contracts. A grower guaranteeing a crop free of velvetleaf could seek a premium, he said.
Hodge said he would apply the herbicide, Arietta, as a pre- and post-emergence spray on his crop this year to kill velvetleaf.
Velvetleaf was discovered in Waikato in 2011 and the latest outbreak occurred in a Southland fodderbeet crop in February 2016.
The Ministry for Primary Industries (MPI) launched an investigation and discovered it came into New Zealand via two contaminated lines of imported fodderbeet seed from Italy. MPI response team member Catherine Duthie said of the 800 farms inspected nationwide, 252 farms in 11 regions were positively identified as having velvetleaf. As well as Waikato, it was found in Canterbury, Southland and Otago.
More than 20 lines of fodderbeet seed coming into New Zealand were tested and four lines were found to have velvetleaf. If left, velvetleaf could spread far and wide because it could produce as many as 17,000 seeds in pods clustered on the host.
‘‘It’s estimated that unmanaged, it can reduce the yields of arable crops by 30-40 per cent,’’ Duthie said.
Farm owners had a responsibility to dispose of any velvetleaf plants found, ideally before it had set seed. If it had gone to seed, the plant should be doublebagged around the seed pods to prevent spillage and disposed by deep burial, such as in an offal pit, she said.
‘‘What we are trying to tell people is that good on-farm biosecurity will help reduce not only the issues from velvetleaf, but from all other pests as well.’’
But Pirongia farmer Alan Henderson said that was extremely difficult. It was also an admission of defeat by MPI that its own biosecurity policies had failed.
‘‘To me, it’s passing the buck from the border control to farmer controls. That’s telling me that we’ll try and do our best on the border, but if we don’t, sorry guys, you’re going to have to do it on the farm and that’s totally impossible.’’
Cleaning down a combine harvester between crops was incredibly time-consuming for contractors and he doubted they would do so during harvest, particularly if they had a narrow window to collect the crop.
‘‘It’s practically impossible to have an individual farm 100 per cent biosecurity [protected].’’
Henderson, who grows both maize and fodderbeet, questioned what assurances there were that fodderbeet seed entering New Zealand for planting this year was free of velvetleaf.
’’That’s a huge concern for the confidence of the growers.
‘‘I’m hesitant to used fodderbeet seed from various companies that I think aren’t up to par. I don’t have it on my property but I don’t want it because I’m a long-term cropping person.’’
The incursion meant biosecurity at the border was more important than ever, he said.
He also wanted assurances that fodderbeet seed coating processes prior to export were free of contaminants. ’’It’s got to be more than pure,’’ he said.