Varieties, new methods drive citrus revival
“What we were getting was what it cost to produce, so we just stopped harvest,” David Arnold recalled. “We picked a handful of the big fruit and let the other stuff just fall on the ground.”
Mr Arnold and his wife Belinda and brother Shaun have about 85 hectares under production over several sites near Waikerie and Ramco.
They are the fourth generation of the family in the region following their great-grandfather, who was one of the first few in the area and also operated paddleboats on the Murray River near Waikerie, and more recently their parents Michael and Meredith.
It’s no wonder harvest occurs all-year-round under the GM Arnold & Son banner. They have about 40 different citrus varieties.
“We start harvest in January-February with the limes and go through to January-March the following year with the Valencias (oranges),” Mr Arnold said.
They also produce red navels, Washington navels, blood oranges, Seville oranges and Satsuma mandarins, as well as lemons, pomegranates, grapefruit, pomelos and Buddha’s hands.
They sell to a number of packing sheds and most of their main citrus production is exported, with strong demand from China and Japan.
The Buddha’s hands go into markets in Melbourne, Sydney and Queensland and the pomegranates are supplied to the eastern seaboard around to Adelaide. Some produce, including quinces, heads to local companies Beerenberg and Maggie Beer. Mangoes have been added to the crop range as well.
Mr Arnold said the diverse range of crops grown allowed important early market access for some of their produce.
He said their whole orchard management system had changed significantly over the past decade, including spraying treatments and timing of applications, nutrition, irrigation, closer monitoring and more pruning and hedging to provide for open trees. “Our tree health has improved dramatically.”
The Arnolds invested in one of the first Interlink Power Prop 900 citrus sprayers used in South Australia and they switched from spraying in the dry middle of the day period, which Mr Arnold said was a waste of time, to the cooler morning and night time periods. “We also ensure trees are well watered before any spraying and we drive around and assess the trees. We are watching everything so much more closely.”
In March-April of 2012, their Washington navel orange trees were covered in scale.
He said they turned to using the systemic and integrated pest management (IPM) friendly insecticide Movento for the first time and two weeks after application, half of the fruit was clean. “The scale just dropped off.”
They had previously used contact insecticides like chlorpyrifos with summer spraying oil. “With all those contact insecticides, you are not sure if everything is getting hit, whereas with Movento you know it’s getting everywhere,” he said. “With its systemic nature, it was very good.”
In addition to scale, Movento controls Kelly’s citrus thrips and suppresses citrus mealybug, while it is also used to control silverleaf whitefly and various aphids in a range of vegetable crops, stone fruit, mangoes, grapes, pome fruit and cotton.
Unlike most systemic insecticides, which after leaf uptake are mainly translocated in plants’ xylem along with water and nutrients and are transported upwards, Movento, from Bayer, is translocated in plants’ phloem as well as xylem, resulting in transportation upwards and downwards to plant parts.
It can better control sucking pests hiding on covered inner leaves than other insecticides, as well as populations that may have developed resistance to existing registered products.
It is also highly compatible for tank mixing with other products and is “soft” on most beneficial species when used as directed, including parasitoids, syrphid flies, lacewings, predatory midges, ladybird beetles, predatory bugs and earwigs.
Mr Arnold said they don’t release beneficial insects every year.
Movento has been applied at up to 40 mL/100L of water and using up to a 3000 L/ha water rate.
“With water volumes up to 3000 L/ha, it covers the trees to the point of run-off,” he said. “We initially did some tests with Movento and water rates, and we did some dye testing on the runoff.”
They generally carry out one application, with up to two sprays in the lemons only. “We spray after flowering, around about mid-October,” he said.
“In the first year, it was just in the navels, then in certain blocks only because we always got halo damage (from the thrips). In the second year we sprayed it on everything, including baby trees.
“We still get some wind marking, but we don’t get halo damage and I don’t even bother looking for scale now. Mealybug is also not such an issue any more. If we found them to be bad, we would go with an insecticide during the season – we still need to look at some options to mix up the chemistry.”
In terms of nutrition, Mr Arnold said they were applying more potassium and phosphorus.
He said their foliar nutrition program had also gone from two to three applications up to 10 applications, including spraying in the off-season to help flowering and the following crop. The nutrition program had helped to reduce fruit splitting.
The irrigation uses Ray Jet, Microjet, Waterbird and drip systems, and also is automated, allowing for better timing of applications
Source: Australian Tree Crop magazine