Mechanizing insect scouting is winning converts for its efficiencies in the fight against Asian citrus psyllid.
The pest vectors huanglongbing, or citrus greening. Knowing precisely when psyllids appear in a grove, in what numbers and at which life stage helps growers target spray programs more effectively.
“In light of all these diseases, our window for making these [application] decisions is shortening,” says Holly Chamberlain, owner of Pest & Disease Management LLC in Avon Park, Fla.
Chamberlain built the first prototype of the truck-mounted Flicker in 2010 and applied for a patent earlier this year.
Depending on tree size, the device brushes as many as four vertical baffles through foliage to dislodge insects onto two horizontal sticky cards in front of and behind each baffle.
A needle in a haystack
Growers can lease the devices or contract with the company for the scouting service.
“It’s more thorough,” says Shaw ron Weingarten, agricultural technical services specialist for Oviedo, Fla.-based A. Duda & Sons. “It’s more efficient per unit of time.”
Duda has hired Chamberlain’s company to scout 1,100 acres of citrus groves once to twice per month over the past year; the frequency rises during the growing season and drops in winter months.
Tap and visual scouting tend to focus on branches at eye level and below, Weingarten says. The Flicker can cover the full tree height and touch every tree it passes.
That’s particularly helpful where psyllid populations are low.
“There’s no threshold with psyllid,” he says. “If you’re looking for a needle in a haystack, this is the only device I know of to find it.”
During comparison tests where scouts took tap samples on 10 trees in each corner and center of a block, the Flicker always caught more psyllids, Weingarten says. Manual scouting may result in one or two of the target pests; the machine’s sticky cards consistently show three to four times that number.
“You don’t have psyllids if you’re not really looking,” he says.
The pros and the cons
“No sampling method is absolute,” says David Hall, research leader at the U.S. Agricultural Research Service’s horticultural research unit in Fort Pierce, Fla. Hall has run comparison tests on the Flicker to validate it as a sampling method.
Tap sampling doesn’t provide the best results for new plantings under a meter tall. Sticky traps are costly, and weather conditions can skew their results. Without precautions, sweep nets may spread canker.
The Flicker shines when psyllid populations are low or when gauging population levels in a grove over time, he says.
Brushing foliage dislodges some leaves, twigs and other debris. All equipment must be disinfected between blocks to prevent spreading canker, Weingarten says. Avoiding dewy conditions also helps reduce that risk.
As an extra precaution, Duda uses the Flicker only in valencia groves, he says.
Chamberlain says the device removes some subjectivity from manual scouting that depends on individuals’ skill and judgment.
The scouting cost per acre depends on grove size, she says.
Helping fine-tune psyllid control
Tap tests and sweep nets don’t provide a broad perspective of what’s happening in a grove, says Alan Jones, president and owner of Jones Potato Farm in Parrish, Fla. He brings in the Flicker to scout his groves every few weeks.
Growers need to know exactly what their sprays are targeting to fine-tune a psyllid control program, he says. But beyond that, the device provides a better idea of what other pests and beneficials also should be considered.
And, by scouting a row at a time, the Flicker allows him to test the impact of different products and practices.