An electronic trap for monitoring insect pests will free up growers or employees from the chore of checking trap catches every week in the field. The battery-operated trap, well under development, will allow them to monitor trap catches online in real time.
The project to develop the trap is part of a national research program on labor-saving technology called Comprehensive Automation for Specialty Crops. Dr. Vince Jones, entomologist at Washington State University, who is a cooperator in the project, said that as orchards expand in size, driving around checking traps in the field can be a considerable expense, particularly as the cost of labor and gasoline increase. Electronic monitoring should be easier and cheaper.
Dr. Johnny Park at Purdue University is handling the engineering aspects of the device and will commercialize the new “Z-trap” through his company Spensa Technologies, Inc., in Indiana. Entomologist Dr. Larry Hull at Pennsylvania State University is also involved.
When they began, three years ago, the researchers envisioned that an electronic trap would contain a wireless camera to identify the insects caught, Jones said, but that proved impractical because of the small size of the insects and because they’re not all oriented the same way when they land in the trap. It also wouldn’t relieve growers from the task of going out to change the sticky bottom periodically.
Early on in the project, the researchers used bucket traps with pheromone lures and an infrared beam that, when broken, indicated that an insect had entered the trap.
Hull and Jones did studies to find out what color the trap should be in order to discourage nontarget insects, such as flies or honeybees, from entering the trap and making it more difficult to identify codling moth.
The team found that orange worked best for keeping those insects at bay.
The bucket traps contained insecticide strips to kill the trapped insects, but a problem was that they reduced trap catch, presumably because the insects could sense the insecticide before entering. Another problem was that the infrared beam consumed too much power and batteries were only lasting a day or two.
The researchers switched to a Delta (triangular) trap with a zapper in the form of a coil with a pheromone lure inside. The insect hits the coil, is electrocuted so it doesn’t escape, and falls into the trap. The electic current from the coil can be analyzed to identify the specific insect. A larger insect will have a different resistance to the zap. By design, the insects are only stunned instead of killed by the coil. More battery power would be needed to kill insects, and those killed would likely be burned on the coil and cause additional interference.
The scientists made further changes to improve its energy efficiency and ensure that the design of the trap didn’t interfere with the flow of the pheromone plume from the lure.
The latest version has a battery that can last up to eight weeks. In the field, the trap would operate for only six hours a day, starting a couple of hours before dusk, when the codling moth is likely to be flying. The goal is to get the longevity of the battery to match that of the pheromone lures, which is two to three months, to minimize the maintenance required.
Traps will have Global Positioning System coordinates so that catches can be mapped. Growers will be able to access a Web page and look at the types and timing of trap catches in different parts of the orchard over the whole season. This will allow them to use spot treatments for hot spots and perhaps understand why more insects are being caught in certain parts of the orchard. For example, traps near a bin pile might catch more insects.
The trap could be used with multiple pheromone lures to target more than one species—as long as the pheromones don’t interact or interfere with each other, Park said.
A dual pheromone lure to monitor both obliquebanded leafroller and codling moth is under study. Hull is working on a version of the trap for apple tufted bud moth and oriental fruit moth, which is a smaller insect that is able to fly back up the funnel of the current model.
The Delta trap has proven far more effective than the bucket-style trap, Jones said. “With the Delta trap, we’ve caught 20 percent more codling moth. We got over the big hump of trying to ensure that we actually trap insects in comparable numbers to standard traps.”
When traps can be checked remotely, it should be feasible for growers to increase the density of their traps, Jones said, and it would be a huge advantage if they are able to monitor pests more intensively. Previous research has shown that when traps are placed at high densities, there can be differences in the numbers of insects caught in traps only 30 to 50 feet apart. Jones would like to see growers use one trap per acre, whereas the current standard is one trap per five acres. The more traps, the better picture the grower has of what’s going on in the orchard and how to respond, he said.
Park noted that a large-scale test is planned for next year, with additional refinements to the device. “I have an aggressive goal to have the Z-Trap commercially available by 2013,” he said. The retail price is not yet known.