You may have seen small trees covered in white sheets on hills along highways. They protect citrus trees from the Asian citrus psyllid, which causes citrus greening disease. New research from the University of Florida shows that trees grown under the individual protective covers (IPCs) continue to grow well for several years after growers remove the bags.

Typically, growers remove IPCs from trees after two to three years, leaving them exposed to psyllids that can transmit the deadly citrus greening disease. But this study showed that the fruit remained healthy.

“We monitored the trees for three years after removing the IPCs, and we saw a significant improvement in fruit yield and quality, even though the trees became infected,” said Fernando Alferez, associate professor of horticultural sciences at UF/IFAS. “It is worth noting that fruit quality declines over time after the covers are removed as the trees become infected, but it is still better than the fruit quality of the uncovered trees.”

High quality in this case means that the fruit contains more Brix – a measure of the amount of sugar.

Alferez and his colleagues also found that trees once protected by IPCs produced better quality fruit 30 months after they were planted. Because the fruit is of such high quality, growers can achieve economic returns as early as two and a half years after planting. “This is not the case when trees are planted without protection,” said Alferez, a faculty member at the Southwest Florida Research and Education Center.

There are two reasons for this. First, it is highly unlikely that trees not protected by IPCs will be able to bear fruit two and a half years after planting, Alferez said. Even if they do bear fruit, they have been infected for more than two years, so the fruit quality will be poor.

Over the past seven years, about 1,000 citrus growers have used IPCs to keep the psyllids off their trees after Alferez tested them and provided solid scientific data proving their effectiveness. These growers represent a significant portion of citrus growers in the Southwest and Central Florida, according to Alferez.

Florida citrus growers have been searching for solutions to citrus greening disease, also known as huanglongbing (HLB), for the past 20 years. The disease has damaged much of the state’s citrus crop, but UF/IFAS scientists are trying many methods to keep the industry alive. Currently, the use of IPCs is the best method to protect young trees from the disease.

Source: blogs.ifas.ufl.edu