By Owen “Sonny” Conner
EDITOR’S NOTE: Citrus Industry magazine is providing a platform for growers to express their experiences and share their stories as we unite in the quest to fight HLB and bring the citrus industry back to a healthy condition. The views stated in this article are those of the author and do not represent those of AgNet Media, other contributors or our advertisers.
On behalf of a family partnership, I manage a grove on land in Lake Gem, Florida, that my family has had in citrus for 120 years. We have experienced all the problems and disasters that have come along during those years. But no challenges equal what our industry faces with HLB. While millions of dollars are being spent on research to find the ultimate answer, growers are learning to deal with the disease to stay in business.
There have been many changes since I received my degree in citrus production from Florida Southern College in 1961. But certain things remain the same. A tree still has two parts, the top and the root system. They still are mutually dependent. By 2013, we understood a large percentage of our citrus tree roots had died.
One of the basic tenets of science I was taught was to question everything. Advice was given to identify and remove infected trees. I rejected that approach as having a predictable result when the disease was obviously ubiquitous. A large grower told me he came to the same conclusion after clipping 600,000 trees. Apparently nothing was learned from the canker 1900-foot rule.
I chose to take a holistic approach to the problem. I felt that if possible, we should take steps to regenerate the roots. If that was going to be possible, I intended to provide an ideal environment in the soil for new root growth.
The first step I took was to apply over 8 tons per acre of a high-quality organic mulch. This has several purposes: to increase microbial activity in soil, modulate soil moisture, prevent leaching of nutrients and allow growth of a heavy cover crop. This was a return to my father’s method when we produced 800 boxes of oranges and 1,000 boxes of grapefruit per acre without irrigation and only 70 trees per acre. Importantly, the cover crop provided a home for huge numbers of beneficial insects such as green and brown lacewing flies, ladybugs, spiders, etc.
Back in about 1970, I was involved in foliar feeding of row crops and some citrus. At that time, the scientific community rejected the idea that foliar feeding would work on citrus because of the waxy nature of the citrus leaf. However, I saw positive results on groves managed by Jim Rock in Fort Pierce. I am sure that advances have been made in the development of foliar fertilizers in the last 40-plus years.
In the mid-1970s, I met a liquid-fertilizer manufacturer by the name of Carl Fabry. I came to realize he was and is “Mensa smart.” When I learned he was producing foliar-grade liquid fertilizers through a patented process which produced a new molecule, I called Carl and set up a meeting with his even smarter son, Paul, at their office at Plant Food Systems in Zellwood, Florida. I began to use some of their products and saw an immediate result.
In December 2015, we placed 20 acres of Valencias on a complete program of foliar feeding. We applied 11 annual foliar fertilizer sprays of six different products to target the physiological needs of the trees. Bactericide/fungicide applications were made three times per year in March, June and September through irrigation. We adjusted pH/bicarbonate levels in our irrigation water with a product supplied by Plant Food Systems. We also installed a system to monitor soil moisture, which uploads to the internet so I can police plant-available water on my smartphone. This allows me to control soil moisture very efficiently.
With Paul’s help, we modified our dry-fertilizer program through use of calcium nitrate as much as possible for a nitrogen source, which includes 200 pounds per ton of Tiger 90 sulphur. This grove has high levels of calcium and magnesium left over from years of the standard practice of applying 1 ton of dolomite per acre every year. That, plus high bicarbonate levels and the nutritional needs of the trees, dictate the application of sulphur. This grove had been under volume-gun irrigation for several years previously. We no longer spray sulphur for rust mites.
Our dry fertilizer program entails calcium nitrate in January to supply 50 pounds of nitrogen per acre. In March and June, 16-0-10 supplies 45 pounds of nitrogen per acre. In September, 12-0-16 supplies 40 pounds of nitrogen per acre. Both analyses apply 1.9 pounds of calcium, 2.9 pounds of magnesium and 0.09 pounds of boron. No limestone filler is used.
I only make two targeted sprays for psyllids annually — postbloom and early fall. We target rust mites, leafminers and psyllids when we foliar-feed. We sprayed oil three times this year. I consistently have zero or near zero psyllid taps. I personally think some growers overspray for psyllids to the point where they wipe out beneficial insects, but are not treating the disease in the trees.
Our other challenge, during the last two years, has been postbloom fruit drop (PFD). There are two computer models that predict when to spray for PFD. These models work best when you put the computer in a closet and get boots on the ground every morning at daylight and look for blossoms. When the blooms are about twice the size of BBs, it is time to spray. Once that bloom is the size of a black-eyed pea, you have probably lost the battle if you are not putting on your third spray. If you don’t know how big BBs and black-eyed peas are, you have no business in agriculture. We are successful with ferbam and Abound for PFD control.
Our nutritional spray, water treatment and bactericide/fungicide applied through irrigation costs approximately $650 per acre. Other costs are particular to the individual operation. Dry fertilizer costs swing and application costs swing, as well as herbicide needs, water removal and other variables such as canker suppression can vary. Fresh fruit programs in some areas could be much different.
As a result of our three oil sprays this summer, in addition to postbloom and fall insecticide sprays, it appears our Valencias will pack, and production may be back to pre-HLB levels. We have recently leased 20 acres of Hamlins, which were virtually out of production due to HLB and are now on the same program as the Valencias. We continue to look for more groves to lease and welcome visitors at any time.
Owen “Sonny” Conner (firstname.lastname@example.org) is a managing partner of Ocklawaha Nurseries Partnership in Lake Jem, Florida.
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