With the red clover case bearer moth now added to the velvetleaf, pea weevil and blackgrass incursions, the Foundation for Arable Research (FAR) urged farmers to take action.
The biosecurity risk farmers could influence most was their own property, FAR chief executive Nick Pyke said.
“A robust biosecurity plan is to protect your farm border from incursions of weeds, pests and diseases you don’t have but that may be in NZ.”
While the black grass, pea weevil and velvetleaf incursions were detected through good surveillance, all should have been detected sooner if good biosecurity was in place across the industry.
“For all three incursions the response was complicated by a poor understanding of the problem, then inability to respond in a clear time frame.
“Poorly informed people making statements without the necessary information therefore reduced the effectiveness of the response,” Pyke said.
Some of those issues would be addressed under the new Government Industry Agreement (GIA) for biosecurity, developed to manage border biosecurity.
The cropping industry was developing a GIA of its own, which would involve the formation of a new legal entity.
“We, as part of that GIA shared decision-making and costs, will have a say on what happens at the border.”
But still biosecurity was important at the farm level and all farms should have a biosecurity plan, Pyke said.
An easy-to-use plan was available in the FAR farm environment plan at www.far.org.nz.
Meantime, red clover case bearer moth (Coleophora deauratella), initially discovered in Auckland in October 2016, was confirmed in a red clover crop in Mid Canterbury in February.
Reduced seed yields and damaged seeds from the same paddock last year suggested it might have been present back then, Pyke said.
He urged red clover growers to inspect their crops for the presence of a small moth, typically 8mm in width and to part open flowers to look for drill holes near the base of the floret.
“If you have any concerns or see small moths you can’t identify, try to capture them in a jar and place it in a chilly bin with ice or in the freezer and-or contact FAR,” Pyke said.
Brown larva cases could sometimes be seen on the flower heads and damaged flowers might be dark brown rather than the more usual tan colour.
The red clover case bearer had a high preference for red clover and was a different species to the case bearer that was common in white clover.
Two parasitoids that were released in the 1980s had been very successful and eliminated the case-bearer problem in white clover.
While those same parasitoids were thought to be able to also control the red clover case bearer moth, the level of populations was unknown, Pyke said.
FAR was working with the Ministry for Primary Industries, Federated Farmers and other industry groups to understand more about the moth pest, its impact on red clover crops and how to manage it.
Adding to biosecurity concerns MPI had reported more black grass found growing on three separate properties in Mid Canterbury over New Year.
The plants had been removed and monitoring in the area had been enhanced, MPI response manager David Yard said.
A routine surveillance programme had been in place since the detection of blackgrass seed in harvests of ryegrass from two properties in 2015 and 2016.
Yard said while the latest finds were disappointing they were not unexpected given the previous detections.
MPI was treating the finds seriously and would continue surveillance and monitoring of the properties and other risk sites, including tracing of seed and machinery movements.
The blackgrass was likely to have come from a consignment of contaminated ryegrass imported in 2007.
MPI was surveying 24 other properties that bought grass from the 2007 consignment, Yard said.
In Europe, blackgrass was known as an invasive pest that particularly affected winter crops like wheat, grass seed, rapeseed, forage legumes and barley.
Meanwhile, on the pea weevil front 757 sweeps of 283 pea crops across NZ had been completed with no pea weevils detected outside the Wairarapa exclusion zone.
A small number of crops in Canterbury remained on the monitoring list and were due to be checked by MPI in mid-February.
Wairarapa trap crops had worked well, attracting pea weevils into the crops at all sites.
Trap crops would be planted again next season when it was hoped to see fewer, if any weevils caught.
