FOR many farmers, there are some years in the game you just want to put behind you and move on, and 2016-17 was one of those for South Australian winegrape grower, Andy Murdock.
Born and bred in the Mount Benson wine region on the Limestone Coast in the State’s South East, Andy grows Cabernet Sauvignon, Shiraz and Merlot red grapes plus Chardonnay, Sauvignon Blanc and Pinot Gris white grapes over 60 hectares, as well as faba bean and hay crops over a similar area.
The winegrape production is contracted to Treasury Wine Estates and Dorrien Estate in the Barossa Valley.
North-west wind gales coming off the ocean can be a factor in spring and last year they conspired with soaring scale infestations, enhanced by the unseasonal cool and wet conditions, to significantly restrict production.
“The winds were so strong that some of the inflorescences (juvenile bunches) just got twisted off,’’ Andy said.
Sales representative with EE Muir and Sons at Penola, Ivan Bignell, who assists Andy’s winegrape program, said the winds and scale “hammered’’ a lot of the vines.
“On top of some hills they got smashed – there was nothing there. On some vines there were only a few grapes on a bunch,” he said.
Andy said scale had been around for a few years, however hot and dry springs previously had kept them in check.
He said the wet conditions last season were the trigger for an infestation explosion.
Wind turbines used to prevent frost impact also appeared to fan the scale population in those areas.
Via Ivan, Andy turned to applying the two-way systemic insecticide, Movento, and while it was too late for the application in the Chardonnay vines, he managed to carry out two treatments within the application window in the Shiraz vines.
Movento, from Bayer, has only been available for use in winegrapes in recent seasons for control of mealybug and suppression of scale and thrips.
Movento can be better at controlling sucking pests hiding on covered inner leaves than other insecticides, as well as populations that may have developed resistance to existing registered products.
After leaf uptake, most systemic insecticides are mainly translocated in plants’ xylem along with water and nutrients and are transported upwards.
Movento is translocated in plants’ phloem as well as xylem, resulting in transportation upwards and downwards to plant parts not contacted by the insecticide.
It is also highly compatible with other products and with Integrated Pest Management (IPM) production systems, being ‘soft’ on most beneficial species when used as directed, including parasitoids, syrphid flies, lacewings, predatory midges, ladybird beetles, predatory bugs and earwigs.
Andy has a healthy vineyard full of spiders and, hence, it was considered they may have also played an important role in the areas that received the IPM-friendly Movento treatments.
He applied Megafol and some nitrogen through the drip irrigation in an effort to boost the Chardonnay vines, but unfortunately production was still limited to about 4 tonnes/ha.
They normally yield 10t/ha and in 2015-16 produced 17t/ha.
Where the Movento was applied in the Shiraz vines, they yielded 7-8 t/ha, which was closer to their average production. The winds were also less severe in this area.
Andy said for next season he would likely apply lime sulphur and oil a couple of weeks prior to budburst and then would look to use Movento again during the application window to help continue to reduce the scale population.
“It is just suppression with Movento, but suppression is better than nothing,’’ he said.
- Copy supplied by Bayer.