Lukasz Stelinski for years has promoted saving money on HLB control by spraying for Asian citrus psyllids (ACP) only when their populations reach a certain threshold. The University of Florida Institute of Food and Agricultural Sciences professor still promotes that concept, but with a slightly new twist.
TRUNK INJECTION SHOWING PROMISE
In a virtual seminar on April 25, Stelinski advised growers to use the money saved from unneeded spraying for trunk injection of oxytetracycline hydrochloride (OTC-HCl). Two OTC-HCl products were approved for HLB control in recent months.
In tests, when tree trunks were injected with OTC-HCl, virtually none of the ACP found on the trees acquired HLB, Stelinski reported. That’s in stark contrast to foliar sprays of OTC-HCl, which didn’t reduce the ACP’s acquisition of HLB.
“Trunk-injected OTC treatment seems to be showing promising results, and we should have more data from the field as the season progresses,” he said.
TAP THRESHOLD METHOD
Managing ACP definitely helps tree health, Stelinski said, “but we don’t have to treat every month.” Rather than spraying routinely by the calendar, growers can save hundreds of dollars per acre and not reduce yield by using Stelinski’s threshold method.
He suggested that growers spray only when a survey shows ACP levels are between 0.2 and one ACP per tap of the canopy. Spraying eight times a year would cost $758.70 per acre, versus only $403.09 per year for three sprays, when ACP levels are at 0.2 per tap.
The professor advised spraying for ACP at budbreak and before there is new flush on which adult ACP can lay eggs. Then spray only when the suggested ACP threshold of 0.2 to one ACP per tap is reached. Stelinski emphasized that maintaining tree health is the goal, not stopping HLB spread.
Multi-county citrus Extension agent Mongi Zekri hosted Stelinski’s presentation.
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