Dried fruit growers need to control cordon bunches

Dried fruit growers need to control cordon bunches


Horticulture
VITAL: Dried fruits grower and researcher, Ivan Shaw, says dealing with cordon bunches in spring is critical to producing a profitable crop come harvest time.

VITAL: Dried fruits grower and researcher, Ivan Shaw, says dealing with cordon bunches in spring is critical to producing a profitable crop come harvest time.

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Some time taken in spring to control rogue bunches will pay dividends for dried fruit growers come harvest.

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DRIED fruit growers have been encouraged to think hard about their management of cordon bunching and embrace Australia's world-leading techniques in controlling the problem.

More than 30 growers attended last Friday's workshop at Warren Lloyd's property, Irymple, Victoria, organised by Dried Fruits Australia which aimed to inform and prompt discussion about vineyard management.  

Leading grower Ashley Johnstone, grower and industry contractor Rodney Trigg, and industry innovator Ivan Shaw discussed cordon bunch removal methods and shoot thinning.

Cordon bunches are rogue bunches of grapes that grow off the cordon (the top horizontal branches) and are outside of the fruiting zone, where bunches are dried on the vine just before harvest.

Cordon bunches were traditionally mechanically removed but this is a major time and financial cost for growers. 

DFA consultant field officer, Stuart Putland, said growers would need to make a decision on how to deal with cordon bunches in the next month.

“Removing cordon bunches is critical to efficient mechanical harvesting of dried fruit production on swing-arm trellis,” Mr Putland said.

“Dried fruit growers have two options – remove the bunches early in the season, or harvest them by hand during the time between cutting vines to dry the fruit and the final harvest.”

Mr Putland said chemical removal of cordon bunches minimised the summer pruning operation as there was no need to pay for bunches to be hand-removed and placed on the trellis during harvest.

“The cost of hand removal at harvest is about equal to the value of the fruit – resulting in no net gain in returns,” he said.

The field day also covered the removal of shoots on canes near the cordon.

“This reduces the number of cordon bunches and creates a much lighter canopy in that area of the vine, making jobs like mechanical cutting prior to harvest a much easier operation,” he said.

Ivan Shaw gave a brief history on the development of chemical cordon bunch control up to the point that calcium nitrate was confirmed as one of the best chemicals for the job.

He said experimentation and research was ongoing but results had shown dealing with wayward bunches was good practice.

"It's still a pretty imperfect science but it's a damn site more reliable than it used to be," Mr Shaw said.

"I cannot see how you can grow a profitable crop of dried fruit without dealing with cordon bunches in spring.

"The reason for that is, it's not just the cost, it's the hassle of getting people to do it and the time at harvest time, and it makes it very difficult to mechanically cut.

TRIAL & ERROR: Contract vineyard sprayer, Rodney Trigg, says experimentation has been the key to coming up with a suitable rig for spraying cordon bunches.

TRIAL & ERROR: Contract vineyard sprayer, Rodney Trigg, says experimentation has been the key to coming up with a suitable rig for spraying cordon bunches.

"Timing is everything. It doesn't matter what you are doing in this business - timing is everything."

Mr Shaw also spoke of the work done with another control product called Ethrel but cautioned that it required careful management in order to avoid affecting the entire vine.

"It's something you need to be pretty careful with because it will put a little bit of ethanol into the plant structure and tell it to actually desist with the little berries," he said.

He encouraged growers to do their own experimentation and to be vigilant in documenting what was done.

"Otherwise you won't know what you did," he said.

Rodney Trigg spoke on his insights with contract spraying and the various spray set-ups he'd explored to ensure the chemical was reaching the desired areas while minimising drift.

He said he'd had success with using low pressure and large droplets from four jets at four different angles.

Mr Trigg also stressed how much the weather can play a part in effective spraying.

Dried fruit grower Ashley Johnstone was on hand to back-up the call to control cordon bunches.

"Getting rid of cordon bunches are really critical to your harvest preparation," he said.

THINK AHEAD: Forward-thinking dried fruit grower, Ashley Johnstone, says getting rid of cordon bunches prior to harvesting is critical.

THINK AHEAD: Forward-thinking dried fruit grower, Ashley Johnstone, says getting rid of cordon bunches prior to harvesting is critical.

"You don't want to be going into your harvest with a heap of fruit up in that zone.

"We've got a hard enough job. As growers, we've got to get the fruit ripe and then we've got to go and get it dry.

"So we need every advantage we can get in every preparation leading into harvest."

He also spoke about shoot removal and work he'd done on getting more light penetration into the renewal zone.

Apart from reducing the possibility of cordon bunches, Mr Johnstone said the practice assisted with cane visibility when it came time for pruning.

"If you can do a bit of shoot thinning in the spring time, you can probably halve the number of cuts you need to make along that length of the cordon," he said.

"A little bit of time spent in the spring time, does have its payback in the harvest.

"Any advantage you can get at harvest time is a great help."

A follow-up event will be held in a few weeks to demonstrate spray application techniques and machinery for chemical removal of cordon bunches.

Dried Fruits Australia's Dried Fruits Australia's Annual Conference will be held on October 3 at the Mildura Grand Hotel, including the annual general meeting. 

The story Dried fruit growers need to control cordon bunches first appeared on Good Fruit & Vegetables.

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