World OJ demand, open hydroponics and psyllid control top Citrus Industry Conference

07/14/2011 04:01:00 PM
Vicky Boyd

During the next 30 years, demand for orange juice is projected to outstrip supply by about 2 billion single-strength equivalent gallons.

For Florida growers to take advantage of the boom, they must start thinking about redeveloping existing groves or putting in new high-density plantings today, says Bob Norberg, deputy executive director of research and operations for the Bartow-based Florida Department of Citrus.

World orange juice production has dropped from 3.5 billion SSE gallons in 2000 to about 2.7 billion SSE gallons in 2010.

Brazil accounts for 54 percent and Florida accounts for 30 percent of today’s production.

But orange juice consumption hasn’t dropped as much during the same period. As a result, much of the excess production that was put into inventory during earlier oversupply has worked its way through the pipeline.

“Inventory in both Florida and Brazil is pretty well depleted,” Norberg told attendees of the recent Florida Citrus Industry Conference in Bonita Springs.

As worldwide economies recover from the current recession, consumers will invest more money into food, strengthening demand for orange juice, he says. Because orange juice is income elastic, as incomes rise, so does orange juice consumption.

“If Florida starts to plant trees now, we could pick up a share of that opportunity,” Norberg says.

The opportunity he mentions could be as much as a 2 billion SSE gallon shortfall worldwide by 2040.

But to capitalize on it, Norberg says the Florida citrus industry will have to overcome several challenges, including constraints on the number of trees nurseries can produce and reducing tree mortality from huanglongbing, also known as HLB or citrus greening.

Since 2006, citrus nurseries must propagate trees in a screened facility to exclude Asian citrus psyllid, the HLB vector. The requirement has reduced the number of orange trees they can produce to about 2.3 million annually, he says.

That compares with peak nursery production of about 6 million trees in 1987, long before the protected greenhouse rule, Norberg says. At the same time, growers are replanting lost trees at a rate of about 4 percent or about 2.4 million trees annually.

“We need about 60 [million] to 90 million more trees to meet the opportunities,” he says. “We also need to change the mortality and replanting rates.”

Open hydroponics and psyllid control

Among the other topics covered at the Florida Citrus Industry Conference were:

• an update on open hydroponics, sometimes called the “advanced citrus production system,” at the Gapway Grove near Lake Alfred.

Open hydroponics involves intensive fertigation, balanced and complete nutrition, high tree density, a rootstock capable of developing compact trees and an efficient root system to maximum nutrient uptake.

Arnold Schumann, an associate professor at the Citrus Research and Education in Lake Alfred, is leading the team conducting the research with cooperator John Strang.

The goal is to see if growers can replant an existing grove with a high-density one and bring it into production in this day and age of huanglongbing, also known as HLB or citrus greening.

The grove was planted in January 2009. A computer, hooked up to soil moisture sensors, keeps the root zone near waterholding capacity with short water pulses.

Fertilizer is injected during most pulses. The project also is comparing the open hydroponic system, which uses two rows of drip emitters, to balanced fertigation with a conventional microsprinkler system and a grower standard granular fertilizer and microsprinkler program.

The grower standard involves applying granular fertilizer six times per year and infrequent irrigations.

Already, the plots on drip and microsprinkler fertigated with the balanced nutrition program appear more vigorous and have a larger canopy, Schumann says.

In the end, Schumann says the team hopes to see reduced fertilizer and water use, faster growth and earlier production with the open hydroponic system compared with the grower standard program.

To take a digital tour of the Gapway Grove, visit http://bit.ly/kj9g0l.

• aggressive Asian citrus psyllid control in young trees. Michael Rogers, an entomologist at the CREC, looked at psyllid control from three different soil-applied neonicotinoids: Admire Pro, Platinum 75SG and Belay 50. Belay is registered only for non-bearing trees and has a 12-month pre-harvest interval, something Rogers says Valent USA, the product registrant, hopes to change by 2012.

The neonicotinoids actually disrupt psyllid feeding, reducing HLB transmission, he says. They also provide long-lasting systemic control and target both leafminer, which spreads citrus canker, and Asian citrus psyllid.

Rogers also looked at psyllid control in three different sized trees: resets less than 3 feet tall; 1- to 2-year-old trees 3 to 5 feet tall; and 3- to 5-year-old trees 5 to 9 feet tall. “In young trees up to 5 feet, it takes about two weeks to get consistent control, and you can expect it to last 60 days [after application]” Rogers says.

In trees 5- to 9-feet tall, it takes about 30 days before you’ll see consistent control, and it will last for another approximately 30 days, Rogers says.

For the smaller trees, he recommends more, but smaller, applications. In the larger trees, he recommends one application at maximum labeled rate of Admire or Platinum or two applications with half labeled rate of Belay.

Regardless of the tree size, Rogers says growers should fill in the control gaps with foliar insecticide applications with different modes of action than neonicotinoids.

For his complete recommendations, visit http://bit.ly/iWrZXP.



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