Researchers at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) are looking to increase the efficiency of known Asian citrus psyllid (ACP) control techniques by using them together. The pairing should help control populations of the insect that spreads huanglongbing (HLB) disease.
Bryony Bonning, UF/IFAS eminent scholar and entomology professor, is leading the research funded by a grant from the U.S. Department of Agriculture National Institute of Food and Agriculture. She said the research will focus on two techniques specifically, using them at the same time to create a synergistic effect.
The first method is the use of pesticidal proteins that are produced by soil-dwelling Bacillus thuringiensis (Bt) bacteria. Bonning said the idea is to have the plant deliver the protein so it reaches the insect. “We’ve identified some of the pesticidal proteins that are active against the psyllid and we are pursuing this for the production of plants,” she noted.
The second method is the use of gene silencing RNAs. Researchers can isolate genes in the psyllids and essentially turn them off. Bonning said some of those genes are critical for the insect to survive and would kill the pest if turned off.
According to Bonning, there are silencing RNAs that can kill the ACP and others that can have a physiological effect on the insect, which will make the pesticidal protein work even better. “For example, we have a candidate that increases the volume of sap that is ingested by the psyllids,” she said. “With that combination, you would expect the psyllids to actually ingest more of the pesticidal protein, which would mean that it would work even faster.”
Unfortunately, the ACP is also extremely efficient at vectoring the bacterium that causes HLB. These methods would be a tool for growers to battle the insect, but the pathogen itself still needs to be addressed. Bonning said the combination would be another tool for producers in their fight against HLB disease. “We have some data that if you use the individual components, they do quite well,” she said. “But if you combine them, you can get over 90 percent mortality of the psyllids. It’s really quite effective.”
The research team will try to identify the best combination of pesticidal proteins and silencing RNAs, and then develop the parameters for a grower to use in the field.
Bonning also noted that a trap crop could be used to keep the ACP out of groves. “We’ve actually shown that we get really nice results with Indian curry when we deliver a Bt pesticidal protein from that plant,” she said. “The goal is to make it even better by adding the gene silencing RNA.”
This interview with Bonning is featured in the November 2020 episode of the All In For Citrus podcast, a joint project of UF/IFAS and AgNet Media. Listen to the full podcast here.
This article was written by Taylor Hillman, general manager of AgNet West.