It’s a bug-eat-bug world out there for strawberry growers

Sep 01, 15 It’s a bug-eat-bug world out there for strawberry growers

By: Brad Buck, 352-294-3303, bradbuck@ufl.edu

GAINESVILLE, Fla. — A new University of Florida scientist is trying to find an insect that will eat the fly that’s damaging such fruit as strawberries and blueberries in the Sunshine State.

Such a finding would be critical in Florida, where the strawberry harvest brought in $267 million in 2013, according to the U.S. Department of Agriculture.

Justin Renkema, an assistant professor in entomology, recently developed tools to help determine whether he’s found a biological control for the Drosophila suzukii, commonly called the spotted wing drosophila.

Among other goals of the experiments, Renkema and his co-authors wanted to detect the DNA of spotted wing drosophila after it’s been eaten by a predatory rove beetle. This is a critical test to know whether one insect has eaten another, he said.

“The molecular tools we developed should be useful for testing whether other predators inhabiting fruit and berry fields consume spotted wing drosophila,” said Renkema, a new faculty member at the UF/IFAS Gulf Coast Research and Education Center in Balm.

In their experiment, Renkema and his co-authors also wanted to know how many spotted wing drosophila larvae or pupae a rove beetle could eat. Normally, spotted wing drosophila infest fruit, so they also tested the ability of the rove beetle to enter infested fruit, find the flies’ larvae and eat them.

They found that the rove beetle ate larvae, or immature flies, but not pupae – a more advanced developmental stage — of spotted wing drosophila, so more research is needed.

“There is ongoing research around the world on parasitic wasps that infect larvae or pupae and beneficial fungi that infect adult flies,” he said. “Increasing the abundance and diversity of biological control agents should reduce populations of this pest and help build an integrated approach to management.”

Justin Renkema, an assistant professor in entomology, recently developed tools to help determine whether he’s found a biological control for the Drosophila suzukii, commonly called the spotted wing drosophila. Among other goals of the experiments, Renkema and his co-authors wanted to detect the DNA of spotted wing drosophila after it’s been eaten by a predatory rove beetle. This is a critical test to know whether one insect has eaten another, he said. Credit: UF/IFAS.

Spotted wing drosophila cuts a slit in the skin and lays eggs inside many fruits. The larvae from those eggs damage raspberries, blackberries, blueberries, strawberries, cherries, grapes, peaches and plums. Native to Asia and first found in the continental U.S. in California in 2008, the fly has become common throughout most of the U.S. and North America, as well as in most European countries and southern Brazil.

The study, led by Renkema when he was a post-doctoral researcher at the University of Guelph in Canada, is published in the journal Biological Control.

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