IPCs and Tree Performance

Ashley RobinsonHLB Management

Photo by Susmita Gaire

Preventing HLB infection in newly planted citrus trees with individual protective covers (IPCs) can improve productivity and fruit quality. Thus far, IPCs have kept young citrus trees free of HLB in research plots.

“Once you plant a tree, if it’s not protected, it’s exposed to HLB infection from day one,” says Fernando Alferez, an assistant professor at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS).

Alferez provided IPC research updates during the recent UF/IFAS Florida Citrus Growers’ Institute.


With no psyllids getting through the mesh covers, young trees avoided HLB infection for the 30 months they were covered. Without infection, trees have a significantly better chance to enter the critical fruit-producing stage.

Additionally, IPCs improve tree growth and increased leaf area.

Alferez says insect scouting, as well as pest and disease management, remain necessary practices for covered trees.

“The IPCs actually provide a really good environment for some pests, but also some diseases,” he said. “In our case, we saw a significant decrease in citrus canker incidence. But, in the case of greasy spot and sooty mold, we have more incidence inside the IPCs, probably due to more humidity accumulated inside these covers.”

Some pests, such as scales and armyworms, were also found to be more prevalent in IPCs.


After 30 months, IPCs were removed from the trees in August 2020. In February 2021, the first fruit was harvested.

Based on findings, Alferez says fruit quality was greatly improved with IPCs. The fruit from covered trees had a Brix of 10.9, while fruit from uncovered trees had a Brix of 7.5.

After IPC removal, HLB infection occurred at the same rate, but the covers did offer some delay. Preliminary research data shows that 85% of trees were still HLB-negative six months after IPC removal.

To further maximize the decrease in infection rate, researchers believe combining IPCs with brassinosteroids is a promising strategy to protect young citrus trees. This remains to be fully tested. According to Alferez, brassinosteroids reduced the rate of HLB infection in newly planted trees not covered with IPCs.

View Alferez’s full presentation here.

About the Author

Ashley Robinson

Multimedia journalist

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