By Clint Thompson
Florida citrus growers can add bulimulus snails to their growing list of pest problems. The snails are challenging some citrus groves across the state, says Lauren Diepenbrock, University of Florida Institute of Food and Agricultural Sciences assistant professor and entomologist.
The Damage They Do
Photo by Lauren Diepenbrock
While the bulimulus snails do not do much in terms of physical damage to citrus trees and fruit, they can cause problems in groves.
“The biggest challenge is the impact on irrigation. Those snails will clog up irrigation jets, and they seem to be very good at it. They’re pretty persistent when they get going,” Diepenbrock says. “They can also get inside individual protective covers (known as IPCs or tree bags), and if they get caught in there, they will chew on young foliage.”
She says the snails will be a nuisance for growers with mature trees but for those “with young trees that really need irrigation water during the drought period, because the roots haven’t quite taken hold, I think it’s going to be a bigger issue.”
Diepenbrock has fielded calls about snails for more than two years. The problem has worsened during that time.
“We had not seen them cause a lot of damage on trees until recently. We’re just now seeing impacts in those tree bags,” she adds. “I should preface that by saying most snails prefer to eat dead, decaying vegetation and not so much fresh vegetation. We weren’t super concerned with them and any damage to the trees necessarily, until we saw them in the IPCs.
“I have a grower who had a lot of frost damage this past winter during the late freeze, and it cracked the bark on the trunks of those trees. The snails got into those cracks and have been girdling those trees ever since. The trees can survive the cracks. They are just not surviving the girdling very well.”
The snails can impact citrus grown for the fresh market by defecating on the fruit. “They poop a lot. They get up in your trees and poop all over the fruit. It’s really gross,” Diepenbrock says.
Control Options Scarce
Not only are the snails impacting production, but they also appear immune to any chemical defense that growers might have at their disposal. Any producer thinking about applying an insecticide to control snails should think again, because it’s not worth the trouble and expense, Diepenbrock says.
“I wouldn’t waste your money on insecticides sprayed on snails. Part of the challenge with them is they have detoxifying enzymes. A lot of the chemistries we would think to spray on them don’t really work,” she says.
Diepenbrock says a colleague in North Florida has had success with Lannate providing some efficacy, but it has been used in combination with other physical tactics growers in South Florida aren’t able to do.
“We don’t have any management strategies yet,” Diepenbrock reports. “We have several snail baits that are registered for use in citrus, but it’s all work that’s done in the laboratory. In the laboratory in a container, most of the baits work great. I don’t know how that translates to the grove yet. That’s something we have to test this upcoming year. Baits are our best option, but I can’t tell you which ones are going to work well. There are other materials out there that could potentially work as well.”
Like other challenges that plague citrus production in Florida, additional research needs to be conducted so growers can gain adequate control.
“We’re hoping to get some money this year to do some more research to try to figure out their life cycle and management options,” Diepenbrock says. “Snails are a bigger challenge in other parts of the world, so I’ve been in contact with colleagues in other countries and other regions of the United States to try to get some better ideas of what we might be able to do to manage them better.”