Fortunately for Florida berry growers, 2013 appears to have brought lower levels of spotted-wing drosophila, an invasive fly native to East Asia.

The drop in population, however, comes after a harsh learning year for the U.S. state and a push to safeguard the industry against the potentially devastating pest.

As University of Florida professor Dr. Oscar E. Liburd explained, the state offers ideal condonitions for the fly that thrives off of strawberries, blueberries, blackberries, raspberries and other thin-skinned fruit.

"Florida has more favorable conditions for this fly than probably any other place, with the exception of California. One of the things is that when the berry season is in Florida, it is a cooler time from about January until May," he said.

"The fly tends to flourish quite a bit under these cool conditions. The other thing about Florida is that the temperature doesn’t go low enough to kill the pupae in the soil."

Since its first detection in Florida in 2009, spotted-wing drosophila has spread to 28 counties in the state. In 2012, the presence of the fly dealt a significant blow to growers.

"The big difference between 2012 and 2013 is that in 2012, growers were just finding out they had spotted-wing drosophila. There wasn’t a very effective management program in place for the pest. In 2013, growers already knew they had it. So they developed a proactive treatment schedule for this pest and they were able to manage it much better," Liburd said.

The necessity for strong pest management comes from the frightening reality of what could otherwise occur.

"It could cripple [the industry]. If we don’t develop an effective management program for the fly, the industry will cease to exist. You’re talking about larvae entering the fruit and you just can’t market berries with maggots inside," Liburd said.

The possibility of significant industry damage - especially from newer pests like spotted wing - is not taken lightly in Florida. Liburd's colleague, Dr. Norm Leppla, explained the importance of maintaining research and control techniques to keep the state's agriculture afloat.

"The whole agricultural community tries to predict which pests are coming in at our borders and being intercepted. So we have organizations that their job it to watch and manage trapping, intercept host material, track hosts and maintain databases on what’s been intercepted and where the pressure is coming from geographically. We’re heavily invested in trying to keep these things out," Leppla said.

Management techniques on the farm level manifest in a number of ways, from biological control to pesticides to community monitoring networks. On a larger scale, Leppla explained that the University of Florida is working not just to control such pests, but to understand their origin.

"You begin to define pathways. It’s the answer to the question posed: where are they coming from and how are they getting in?" the Integrated Pest Management director explained.

Among efforts to understand the spread of pests is the development of a database to improve traceability.

"I have a PhD student and she’s working on different datasets to see if we can better predict by looking at past movement of some of these pests," Leppla said.

"I got involved with the Emerging Pathogens Institute here at the University of Florida and they have experts that have been working on datasets for medical and veterinary pests, such as vectors of West Nile virus. So with that expertise, from the agricultural side, I said, why don’t you look at pests for which we have decades of data? And now she’s looking at the Mediterranean fruit fly."

In addition to a pest traceability database, the university is also working to prevent agricultural threats from leaving their point of origin at all.

The Caribbean Distance Diagnostic System, for example, is working to set up resources for pest management in a region known to be a major pathway.

"You can imagine the Caribbean Islands aren’t very big and they can’t afford a lot of entomologists and plant protection people. So they don’t have the capability of identifying what might be in their commodity and do it rapidly," Leppla explained.

"So we set up a system where they can connect directly with the University of Florida and with the USDA’s national identification people and find out immediately if they’ve got a problem and deal with it."

The idea is to create targeted intervention and ease the strain of detecting pests once they arrive to Florida entry points.

As Leppla explained, inspectors can only achieve a certain level of prevention without the help of management systems.

"You can only inspect so much of what comes in and hardly any of the traffic from tourists can be inspected because you’ve got to get them off their ships and airplanes," he said.

"The inspection approach is very important but the level of commerce is overwhelming our inspection system."

Photo: male Drosophila suzukii, Martin Hauser Phycus via Wikimedia Commons

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