AGRICULTURE NEWS - Pome fruit producers in the Elgin, Grabouw, Vyeboom and Villiersdorp (EGVV) region lose thousands of rand annually to sunburn damage.
To reduce these losses, many farmers have started covering higher-value orchards with shade nets. However, the high cost of this is often not justified, especially for older orchards with only a few years of production left.
To help growers overcome this difficulty, crop protection company Nulandis imported Drape Net in September last year. Unlike fixed nets, which require permanent structures, these patented nets are draped over trees like a blanket.
They are not left on the trees permanently, but used when necessary.
“We heard about Drape Net from members of [fruit and vegetable packing company]Two-a-Day, who saw the product in use during a trip to Australia almost five years ago,” says Ebbie Raubenheimer, regional manager of Nulandis.
Drape Net was developed 15 years ago by third-generation Australian fruit farmer Michael Cunial as a cost-effective solution to protect his orchards against hail. It has since also been found to reduce damage to fruit caused by sunburn, insects and birds.
In addition, it decreases cross-variety pollination between citrus trees, helping to increase the number of seedless fruit in seedless varieties and lower the pruning requirements of certain trees, depending on fruit variety and tree architecture.
Australian research also found savings of up to 30% in irrigation water demand during the months that trees were covered.
South African experience
Two-a-Day growers last year purchased 15ha worth of Drape Net to test the nets’ efficiency in apple and pear orchards. Raubenheimer foresees that this area will be expanded to about 86ha in the coming season across the EGVV region.
Daan Brink, a technical adviser at Two-a-Day, says the growers were happy with the results.
“When we do farm trials, I’m usually much more excited about the results than the farmers are, but this time it’s the other way round, which tells me the nets are making a huge difference.”
Orchards under the Drape Net trial produced more grade one fruit than controls, which meant that less handling was required to sort fruit in the orchards. This not only saved time but resulted in fewer fruit injuries.
“Growers using the nets generally produced 20% to 30% more Class 1 apples in orchards protected by the nets than in control orchards. The number of fruit damaged due to sunburn was also 100% lower, at 9,3%, in comparison with the 19,8% of the control,” says Brink.
Some growers reported significantly less codling moth damage to their crop as a result of the physical barrier of the nets.
The nets also reduced evaporation, with less water needed for irrigation.
“According to international literature, water savings of up to 30% are possible when orchards are produced under nets. South African growers usually claim the same results, but Hortgro recently initiated trials to quantify savings scientifically.”
Raubenheimer warns, however, that water-saving presents its own risks.
“When using nets, growers have to alter their management practices to accommodate the new production conditions. In particular, they should prevent over-irrigation, as this can have the same impact as drought stress,” he says.