Phil Stansly: Psyllid Slayer

Metalized plastic mulch is an emerging technology for protecting young trees from Asian citrus psyllids.

By Ernie Neff

Gulf citrus growers had a CHMA (citrus health management area) before CHMAs were popular — even before they were called CHMAs!

Phil Stansly, University of Florida (UF) entomology professor, is among those credited with organizing Florida’s first psyllid- and HLB-fighting CHMA. Others recognized for the achievement include Gulf Citrus Growers Association (GCGA), Florida Cooperative Extension Service and the Florida Department of Agriculture and Consumer Services’ Division of Plant Industry.

HLB was discovered in Florida in 2005, leaving the industry scrambling for solutions to the dreaded disease that had probably already spread northward from South Florida.

The spread didn’t surprise Stansly, who is stationed at the Southwest Florida Research and Education Center (SWFREC) in Immokalee. “Way back in 2003, I told growers at a production managers’ meeting that if we ever got greening, it would go through our citrus like wildfire because there were so many psyllids,” he says.

Rapid and inexpensive aerial application is an important component of Gulf CHMA success, says Phil Stansly.

GETTING CHMAs OFF THE GROUND
Early on, Gulf groves showed some of the worst disease symptoms in the state. GCGA officials and Stansly discussed spraying cooperatively for HLB-spreading Asian citrus psyllids (ACP) over large areas. “He (Stansly) immediately began to promote the concept, and actually Florida’s first CHMA was born,” says GCGA Executive Vice President Ron Hamel.

“We demonstrated early on that ‘dormant spray’ in winter had far-reaching effects by hitting the ACP population before the spring flush, when numbers are down,” Stansly says. “This strategy became the basis of the first area-wide sprays in Southwest Florida in late fall 2008.”

Gulf grower Maury Boyd — renowned for concocting a cocktail of nutrients and other ingredients that have helped him maintain fruit production — also believes staunchly in psyllid control and endorses Stansly’s dormant spray strategy. “It is always better to kill 99 percent of 100 (psyllids) than 99 percent of a million,” Boyd says. “This is why control of ACP starts during the winter months when the population is low.”

The CHMA name was coined after the Gulf initiated cooperative sprays, and the concept spread. Now, Florida has scores of CHMAs, and most growers participate in at least one. There is widespread agreement that nothing is more important than psyllid control in the fight against HLB, and that CHMAs are a key part of the management package. “If everyone in an area isn’t spraying psyllids, unsprayed groves may serve as psyllid refuges and sources for later reinfestation,” Stansly says.

PROGRESS IN GULF GROVES
Growers participating in CHMAS might be heartened by the apparent success of the Gulf’s early adoption of cooperative sprays. Many say Gulf groves now look healthier than most groves in Florida.

Stansly uses National Agricultural Statistics Service data to substantiate that the Gulf has fared better than most Florida citrus-producing areas against HLB. “From the 2008–09 through the 2014–15 season, yield in the five counties of Southwest Florida decreased about 25 percent compared to 50 percent in the rest of the state,” Stansly says. “It’s hard to know exactly what factors contributed to this trend, but we know that early on, most of our growers cranked up their spray programs, including the CHMA dormant sprays. We also benefit from the large scale of many of our citrus operations, which facilitates coordination and efficiency.”

PLANTING WITH PLASTICULTURE
“Lately, we have turned our attention to young trees, which are the future of the industry,” Stansly says. A current focus is supplementing insecticidal control of psyllids by planting trees in beds covered with 4- to 5-foot-wide strips of metalized plastic mulch. “The mulch disorients flight by confusing incoming psyllids with UV light coming from below as well as the sky,” he says. “Plasticulture is typical in vegetable production, but a challenge for citrus growers due to requirements of ground preparation, plastic laying, drip fertigation and chemigation. Nevertheless, advantages are many.”

“New technologies will come along, eventually including HLB-tolerant trees,” Stansly predicts. “Meanwhile, we need to keep a lid on the psyllid population while avoiding insecticide resistance and losses from other pests and diseases.”

WHAT OTHERS SAY ABOUT STANSLY
“While his (Stansly’s) work on psyllids is vital, the agricultural community and the environment have (also) benefitted from his work on control of exotics such as tropical soda apple and air potatoes,” says Gulf grower Hugh English. “Phil’s interest and enthusiasm in his work on a daily basis is a model to follow.”

“Phil is very well respected by our growers,” says multi-county citrus Extension agent Mongi Zekri, who serves the Gulf. “Because of his knowledge, I often invite him to visit growers with me to diagnose problems in citrus groves. Phil is not only an expert in citrus entomology, but he is also a good horticulturist.”

SWFREC Director Calvin Arnold describes Stansly as “an excellent entomologist who really understands pest management in respect to farming operations. He is a problem solver!”

Many refer to Stansly as “hard working,” including Jawwad Qureshi, a UF entomologist in Fort Pierce who worked several years with Stansly in Immokalee. “His work on nutritionals, insecticides and biological control has provided growers with several options of protecting citrus and improving their productivity,” Qureshi says.

“Phil is very focused on conducting his research to help the growers,” adds retired UF entomologist Bob Rouse, who worked with Stansly for 25 years in Immokalee. “His results have been ready for growers to apply immediately and have saved them thousands of dollars.”

Rouse ends his accolades on a light note: “Phil is known for being cheap and not spending money unless he has to. We have yielded to his insistence on a $3 lunch many times just so he would go with us as a group.”

NOT GOING ANYWHERE SOON
Stansly, 72, says he plans to work “as long as I’m healthy and useful. Still, it would be good to have another entomologist assigned to our center to share experience and knowledge before I retire.”

About the Author

Ernie Neff

Senior Correspondent at Large