November 2022

Albedo cause, affect and treatment seminar
It will come as no surprise to growers that albedo breakdown is quite widespread this season across the three major growing areas.
At a Citrus SA seminar late last month, former citrus researcher Michael Treeby said it was improbable that every grower in the Riverina, Sunraysia and the Riverland forgot to apply preventative treatments this season.
So, what is causing it?
“The effect of season appears to us, from our data - from our limited data - to be greater than the degree of control we can deliver by calcium or gibberellic acid (GA),” he said.
“We also know some varieties in this climate, in this environment, are more susceptible than others.”
In the short term, application of GA or calcium seem to be the best forms of defence.
Along with a balanced nutrition program, Mr Treeby reminded the meeting’s attendees that GA application when the fruit is at about golf ball size and January February for calcium applications are proven means of reducing the problem.
“When calcium is a little bit lacking the cell wall material that holds adjacent cells together seems to be weaker,” he said.
“You’ll probably need multiple applications of calcium and coverage is absolutely critical.”
But Mr Treeby says growers should decide which chemical application (GA or calcium) is the best fit for them.
“There’s no point in applying both of them to the same fruit as the effect isn’t additive, you don’t get more response if you apply both, you get one or the other,” he said.
Mr Treeby says a lot of research on albedo breakdown was undertaken in the late 1990s but there hasn’t been a lot since as resources were diverted to post harvest rind breakdown.
“The industry probably needs to review everything that’s been done to date but also need to think collectively about trying to interrogate all the weather data to identify ‘what distinguishes the season we’ve just had from say the previous 20 seasons?’”
He says around 2009-10 the problem was reasonably under control.
“There were still sporadic blocks that had it and had it every season but most people didn’t,” he said.
“So, what distinguished those seasons from these seasons? That’s a bit of an unknown?”
“Weather data are notoriously complex so to try and tease something out of those is a fairly specialised sort of task.”
It’s a task that Mr Treeby said would be ideally suited to a data scientist.
“The ways to interrogate those data have also moved on in the 20-30 years since we first became involved in albedo breakdown research,” he said.
“Computer power is a lot cheaper now so to be able to tease something out of that big, large complex data set is easier.
“The clues are out there and out of those associations you could develop something.”
You can listen to an interview with Michael Treeby on our podcast – The Citrus Segment

AGM October 21, 2022
Citrus SA held its AGM on Friday, October 21 at the Barmera Events Centre. Prior to the AGM, committee member Maria Costi advise she would be resigning from the committee due to work commitments. We thank Maria for her time and contribution during her tenure. Venus Citrus’s grower liaison officer Fabio Spiniello will step onto the committee in Maria’s place. We welcome Fab to the role. Any other interested growers are welcome to contact a committee member or chair Mark Doecke if they would like to become involved.
Read our annual report

Queensland study tour – taking expressions of interest for 2023
Would you be keen to tour citrus growing and packing operations in Queensland in April 2023?
Citrus SA is taking expressions of interest for a group study trip. Please email contact@citrussa.com.au

How much Citrus Gall Wasp is in your block?
Do you know how to calculate the severity of Citrus Gall Wasp infestation in your orchard? The latest Citrus Connect newsletter, published by the New South Wales Department of Primary Industries has the following calculation which you might find useful. It states:
Randomly select 50 or more galls and count the number of galls that are 50mm or longer. If the answer is less than three per cent, the infestation rate is low, if more than 25pc, rate the infestation as high. If the percentage is 3-25pc, the infestation can be rated as low, moderate, or high, depending on its exact value.
A ‘rule of thumb’ is that if the percentage is much closer to 3pc than to 25pc rate the infestation as moderately low. If the percentage is much closer to 25pc than to 3pc, rate the infestation as moderately high. If the percentage is neither close to 3pc nor 25pc, rate the infestation as moderate.
To minimise human bias in selecting galls to measure and count, it is better to select galls by branch, e.g. randomly selecting terminal branches and measure and count all galls, big or small, in selected branches. More galls will give you more reliable ratings.
The above rating method was based on gall size distribution data collected in the southern citrus regions from 2015 to 2018. Other gall size categories (other than 50 mm or longer galls used here) can also be used in rating the infestation level.
Details: Jianhua.mo@dpi.nsw.gov.au or sign up to the Citrus Connect Newsletter

November production tips
Rot spray for mandarins: Three years ago we encountered a season with mandarins showing signs of Alternaria (black core rot). This became visible in the packing shed and later in the marketplace. Alternaria is generally caused by wet conditions resulting from rain, dew, fog and humidity during flowering. This season could present similar problems because of higher-than-average rainfall during flowering. An application of Amistar at full bloom to petal fall as per the label rate could help prevent black core rot. You can read more at the NSW DPI website or contact your grower liaison officer or agronomist.
Hedging and pruning: Hand pruning or machine hedging
Foliar nutrient spray and fertigation: Calcium spray at one per cent calcium nitrate at peas size may help reduce albedo. Potassium Nitrate sprays at 2-3 kilograms per 100/L applied after fruit set and during summer will have a beneficial effect on sizing.
Pesticide sprays: Critical timing to control LBAM, Mealy Bug, thrips, katydid, scales, aphids, Spined Citrus Bug and citrus gall wasp. Aim to apply controls before calyx closure.
Earwigs: Monitor your trees for decline and consult your agronomist or chemical reseller for more information.
Fruit sizing and thinning sprays: 2,4-D 50-200ml/100L at 3000L per hectare. Early applications in November might have some thinning effect (positive on heavy crops). Applications late November or early December will have a sizing effect. Corasil or Tops at recommended rates.
Irrigation: Continue monitoring during warmer months.
Weed control: Knockdown herbicides or residual herbicides as required.

Fruit fly protocol changes

• In June 2022 changes were made in consultation with industry to how commercial host fruit could move around Riverland fruit fly affected areas to provide workable options for commercial growers.

• Continuing with previous controls would have caused unsustainable financial impacts for some growers and affected trade with export markets that do not accept wide-scale use of chemicals to treat fruit.

• The changes were agreed to by all affected industries.

• This change is referred to as Scenario 1.

• Because produce is now moving within and across suspension areas more freely, these changes mean that all outbreak and suspension areas now share a single outbreak reinstatement date

• Moving fruit across suspension and outbreak area boundaries is a special condition that is not normally accepted under the National Fruit Fly Protocol.

• This special condition means Riverland outbreak reinstatement dates and restrictions may be extended for up to 12 months from the last recorded detection rather than resolved within the usual outbreak timeframes.

• Conditions around the reinstatement dates will be confirmed closer to the anticipated dates.