Imagine if your spray equipment could tell where the pests were in your orchard so you could treat only the infested parts of the trees, rather than the whole orchard.
Ted Batkin, president of the California Citrus Research Board, told Washington tree fruit growers that this could soon become a reality, and if it does, it has the potential to reduce the use of spray material in orchards by 90 percent.
The Washington Tree Fruit Research Commission and the Citrus Research Board are jointly funding an effort by scientists in California to develop a robotic harvesting system. The two-part system has a scout, which uses cameras to map the location of the fruit, and a harvester that picks the fruit based on the data from the scout.
During a Fruit School on Competitive Orchard Systems, presented by Washington State University Extension and the Tree Fruit Research Commission in January, he reported on a companion project that the Citrus Research Board is sponsoring.
Scientists are developing a sensor that will be mounted on the scout so that as it moves through the orchard it can analyze volatile organic compounds (somewhat like distress signals) given off by the trees, and detect changes that might indicate if the trees are infected by disease.
The sensor, which is called a differential mobility spectrometer, might also be able to pick up volatiles that insects and mites give off to determine if the trees are infested, he said.
The scientist working on the sensor, with this in mind, is Dr. Cristina Davis in the department of mechanical and aeronautical engineering at the University of California, Davis.
The sensor is proven technology, Batkin said. Such "artificial noses" are already used for detecting explosives and narcotics, and by the oil industry for detecting hazardous vapors.
They are relatively inexpensive and easy to maintain. However, they are larger than the one envisioned for detecting orchard pests. The sensor that Davis is developing will be about the size of a deck of cards.
Batkin said a basic version of the sensor, which would look for easy-to-detect volatiles, such as pheromones, should be ready to test in the field this year. It will then be refined to detect other volatiles.
The sensor could continue to be updated as data on new organic volatile compounds comes along, he said. "As you get new metabolic markers, you just feed them into the system. You don’t have to create a new system. You just plug the new data in, and you’re up and running almost instantly."
Batkin envisions that the sensor would be mounted on the scout near the cameras, and the data would go into the same database as the pictures to produce not only a photographic image of what’s going on in the orchard, but a volatile reading indicating what’s going on in the plant.
"Imagine a system that could go through with the VOC