Results from a UF/IFAS research study indicate that bactericide injections are more effective than sprays.

Florida citrus growers have been using bactericides since the EPA approved an emergency exemption allowing them to use foliar applications of the bactericides oxytetracycline and streptomycin in 2016. However, many growers have felt that bactericides have not been effective for the costs of sprayings. According to a Citrus Industry article, a recent UF/IFAS study indicated that bactericide injections (which are not approved in Florida) are more effective than sprayings. See the details of the article below.

Bactericide Injections Research

UF/IFAS Citrus Research and Education Center (CREC) director, Michael Rogers, said in the article “In concept, bactericide sprays support the health of affected trees by reducing populations of the greening bacterium within the tree, or at least by holding the populations in check. But one challenge is the oxytetracycline needs to get into the tree tissues where the bacterial colonies are.”

The research study utilized two separate citrus tree plots for testing, a CREC research greenhouse and an outdoor commercial citrus grove in Auburndale. There, trees were either treated with foliar bactericide sprays, given injections, or sprayed with water as a control group.

Rogers maintained that “Our researchers did not have much success on that front using foliar sprays, and saw no significant effects from the treatments. However, they did get good results when they applied oxytetracycline with trunk injections.” Testing the citrus leaves treated with sprays showed minimal or no bactericides and “little change” to the levels of the bacteria that cause citrus greening.

Trees given injections, however, had increased levels of bactericides and decreased levels of citrus green bacteria. “In both the greenhouse and the field studies, when trunk injection was used, there was a strong correlation between the amount of oxytetracycline residue in the leaves and the concentrations of the greening bacterium found within the tree tissues,” Rogers explained in the article. “We believe that trunk injection is a promising delivery method for bactericides and plan to continue investigating its potential.”

Another UF/IFAS study is looking at utilizing a robotic arm to inject bactericides in an effort to reduce human error.

Griffin Fertilizer is committed to helping both growers and ranchers make sound agronomic and economic decisions in order to maximize the health of their grove and pasture. As a full-service custom dry & liquid fertilizer blender and crop protection product distributor, we will continue our mission to further advance Florida agriculture. For questions or concerns about your farm or pasture, contact us and one of our team will be in touch.