Socking Psyllids from Day One

Recently, a number of pesticides have received labels for psyllid control applied at low volumes. According to Orange-Co’s vice president of grove operations, Jerry Newlin, this one research hit has the potential to save Florida growers more money in psyllid control costs than their entire $18 million investment into research.

“The savings will really vary based on how aggressive a grower’s psyllid control program is and how much they dedicate to application costs,” says Newlin. “But, I don’t think it is unreasonable to say an average saving would be in the $50 per acre range. For some it would be less, and for some growers like us, it would be quite a bit more.”

Aggressive From Day One

“Our goal from day one was to be as aggressive as we possibly could in fighting greening,” he says. “We’ve been doing that ever since, learning and tweaking our program as we go, and getting better at it.”

Newlin says his team follows the UF/IFAS recommended program which includes scouting for greening, removing infected trees, and psyllid control. Groves are scouted four times per year, but plans are to inspect greening hot spots more than four times to focus mitigation efforts in those areas. Infected trees are removed within 24 hours of discovery, and the company has two full-time scouts in the groves looking for psyllids.

“Within 12 months of starting our program, we got psyllid numbers down very low and literally have kept them low since that time,” he says. “It has come through aggressive scouting and spraying to control the psyllid.

“Fortunately, our cumulative infection rate is still running at below 1%,” says Newlin. “With our program in place, we hope and believe the numbers will continue to stay low.”

Three-Pronged Attack

While Newlin is excited about the recent registration of several pesticides for low-volume application for psyllid control, he says it will be in the mix with his other psyllid control methods. Outside his systemic insecticide applications (imidacloprid and aldicarb), his contact applications will now have three prongs.

He will continue to use his air-blast rear sprayers, with 1,000-gallon tanks, which are PTO driven. Through experimentation Newlin has found that they can do a good job running at 3 mph and with a volume of 50 gallons per acre.

“We will continue to use fixed-wing airplanes for psyllid sprays,” says Newlin. “I am a big fan of aerial applications because they do an excellent job controlling the psyllid.”

Newlin adds that the new third prong of attack on psyllids using low-volume applications is still being perfected.

“We are running the mist applicator regularly now after trying to learn what works best,” he says. “We intend to have three applicators next year and run them in greening hot spots as sort of a fill-in between the air-blast and aerial applications.”

Cooperation Nets Results

According to Newlin, the idea of low-volume spraying for psyllid control came from Brazil. If the technique worked, he knew growers in Florida could save a lot of money.

“The problem at that time was we didn’t know of any chemicals that were legally labeled for low-volume application to control the psyllid,” he says. “So at that point, we got with Michael Rogers, an entomologist with UF/IFAS, and he said if we can prove that low-volume sprays control the psyllid, we can work with the Florida Department of Agriculture and EPA to get the necessary testing for a label change.”

Orange-Co volunteered to cooperate with IFAS researchers on efficacy trials with a number of insecticides to see how they would control psyllids at low volumes. The results were convincing that they would do just that.

At about this time, Newlin learned that work was already being done to seek label changes on a number of products for low-volume psyllid control. There was one problem in that the testing required for the label changes was very expensive. Products have to pass residue tests to prove safety before a label change can be approved.

“I wanted to meet with the guys involved in this, because I represented the Florida Citrus Production Research Advisory Council (FCPRAC) box tax and was chair of the Florida Citrus Greening Task Force,” he says. “These guys had stepped up to the plate, along with the IR-4 Project, which agreed to do the residue testing. They gave us a proposal, which I took to FCPRAC, and we agreed to fund the label-change project for three products with our box-tax funds.”

FCPRAC funded research on three products: Mustang (zeta-cypermethrin, FMC Corp.), Delegate (spinetoram, Dow AgroSciences), and Micromite (diflubenzuron, Chemtura Corp.). Meanwhile, a group of growers discovered a number of products that they believed had no restrictions on low-volume applications, which the Department of Agriculture confirmed. In addition, other chemical companies were seeking label changes. The net result of this hard work and industry cooperation is eight different insecticides are labeled for low-volume applications to citrus for psyllid control.

Seeking Answers

Jerry Newlin says his team at Orange-Co is constantly experimenting with ways to fight the psyllid and greening. There is research being conducted to discover what properties in the guava plant appear to repel the psyllid. That is unknown, but Newlin is taking advantage of that property to see if it can help protect young citrus trees. The experiment is to take young trees out of the nursery, plant them in pots, and surround them with guava where they should be protected from the psyllid by its repellent quality. The trees are not planted in the grove until they have passed their most vulnerable time to greening at age three. In addition, the trees will be capable of producing harvestable fruit at the time of planting.

An insectary is being built on the Orange-Co property as well, where parasitic wasps will be raised by the thousands to be released in the grove to feed on the psyllids. Newlin says he’s not sure how the project will work, but it is another example of their constant search for ways to better control psyllids.