27 October 2021, New Zealand: The ability to control Powdery mildew in the pipfruit orchard of Murray Shearer, in the Hawkes Bay region of New Zealand has been enhanced in recent years as more products come onto the market.
Mr Shearer said there are more tools in the toolbox and that has helped to prevent a disease which can cause major issues in the orchard.
“One of the issues we have is that the newer varieties are more prone to Powdery mildew,” he said. “The variety Envy makes up about 80 per cent of our orchard and is quite susceptible.”
“At one stage, Powdery mildew was a big problem but now we do have a lot of products to choose from. One of the products is Talendo® which has proved to be very good. We’ve been using it for six years and it’s a key part of the program.”
Talendo®, from Corteva, works on three important stages of the disease life cycle by making exposed spores unviable, inhibiting spore germination and preventing Powdery mildew from reproducing, for a cleaner orchard into the future.
Mr Shearer said a typical Powdery mildew program started with Neptune first up and then an initial application of Talendo®. This is followed by Fontelis® fungicide and a range of other options before a return to Talendo® to protect the apples trees at vital stages in late November and early December.
“If you can get Powdery mildew under control by mid-December you can knock off for Christmas,” he said.
“The high-pressure period is during leaf growth, so we need to protect against Powdery mildew at this vital stage.”
He said the range of products available meant Powdery mildew could be controlled although that has not always been the case.
“I have seen some blocks that you would have to walk away from.”
The fungicide program implemented at the orchard rotates several modes of action to help delay the onset of resistance and help each product remain viable for years to come.
“If you overuse chemistry, you will get resistance,” Mr Shearer said. “It will destroy it for yourself and everyone else.”
The program is developed in conjunction with the local Fruitfed Supplies representative who also advocates a balanced approach of chemistry to maximise disease control and minimise the chances of resistance.
Products are selected with withholding periods in mind as well as their effectiveness.
Mr Shearer said the orchard was also part of the Integrated Fruit Production (IFP) program to justify the spray applications for pests and diseases.
This has included an effort to keep and encourage beneficial insects which has helped reduce the incidence of pests such as woolly aphid and mites.
“If you spray with the wrong chemical, you can kill the predators,” he said.
A benefit of having Talendo® in the program, particularly at the key parts of the season, is its minimal impact on key beneficial insects.
Talendo® also has low impact on the environment and a good safety profile for the spray operator and other orchard staff or visitors.
Mr Shearer said their overall spray program was to produce high quality fruit and they aimed at, and regularly achieved, a pack-out rate of between 80 and 85 per cent.
“With a variety like Envy the customers are particularly fussy, so every apple has got to be a good one,” he said.