The latest research by the Department of Agriculture and Food at its Gascoyne Research Station has heralded the value of protective netting in improving citrus quality and quantity.
Researcher Amanda Annells said the Gascoyne climate and good water supply had the potential to provide top quality fruit, but sunburn, wind damage and pests had restricted access to premium markets.
"The red-fleshed grapefruit industry has halved in value in recent years, with nearly a third of growers removing their trees because rind damage was rendering fruit unsaleable," Dr Annells said.
"Netting is used extensively to control pests and environmental damage to fruiting crops in other places, so the Department of Agriculture and Food decided to give it a try."
In 2005, a protective structure was built at the Gascoyne Research Station to see if this could be applied to the local citrus industry.
The first trial of thin-skinned easy-peel navels was planted in 2006.
The recent harvest is indicating that three varieties Newhall, Navelina and the red-fleshed CaraCara, are all benefiting from the shelter.
Trees growing inside are significantly larger in trunk circumference and produced more fruit.
For example, the average number of marketable fruit per tree of Newhall inside the net was 22.1 compared with only 4.4 fruit on the outside.
Yield averaged 6.4kg/tree on the inside but only 1.3kg/tree outside.
Protected trees also yielded significantly more Class 1 fruit.
"Citrus grown outside protective structures usually only produce their first crops in year four with full production by year eight," Dr Annells said.
"Under the netting we have halved the time to the first crop without undue stress on the trees."
Fruit grown under protection also had fewer blemishes, but these were not fully eliminated.
Most blemishes in Carnarvon are caused by fruit rubbing against each other or against twigs and leaves.
"Research will continue to improve pruning and other tree management to reduce this blemish level further, but these results are very encouraging for the Carnarvon citrus industry," Dr Annells said.