Why Citrus Growers Should Keep Spraying for Psyllids

psyllid

lukasz stelinski

For several years after HLB was detected in Florida in 2005, most citrus growers and researchers agreed that it was essential to spray aggressively for the Asian citrus psyllids that spread the disease. In recent years, however, many growers have questioned whether it still makes sense to spray for psyllids when 100 percent of groves are infected, as is the case in Florida. University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researcher Lukasz Stelinski addressed that question at Citrus Expo in August.

“It’s a logical question (for growers) to ask: ‘Does it make economical sense to continue investing in insecticide sprays if I’m already (HLB-) infected?’” Stelinski says. He says previous research by fellow UF/IFAS entomologist Phil Stansly “showed a positive impact on yields with insecticide sprays.” That means that “there is an economical benefit to maintaining the psyllid populations as low as possible under a situation where there’s a 100 percent infection,” he adds.

Stelinski says he is attempting to answer the question, “What is the mechanism underlying this?”

“One of the hypotheses is that an infected tree can still yield better depending on the severity of disease,” Stelinski says. “And we believe that multiple infections lead to more severe disease and therefore more drastic decline of the tree and associated yield decreases.” He began research in January to investigate that hypothesis in laboratory and field experiments, “trying to find what level of psyllid management is required” to get economic benefits. He would like to be able to “actually make recommendations for how much psyllid management is good enough.”

But he emphasizes that “insecticides do matter” and that keeping psyllid populations low provides an economic benefit.

Hear more from Stelinski:

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Ernie Neff

Ernie Neff

Senior Correspondent at Large