Citrus Research

Helping Citrus Trees Resist Postbloom Fruit Drop

With fungicides on the wane, look to the plants’ own defenses for control. Citrus groves have been so devastated by Huanglongbing (HLB), it’s easier to forget that there are other diseases to manage. With 2019 set to be a  strong El Niño season, postbloom fruit drop (PFD) is one of them. The El Niño weather pattern causes more frequent rain during the winter and into spring, which creates excellent conditions for Colletotrichum acutatum, the fungus that causes PFD. Because PFD can cause 20% to 80% fruit drop, depending on its prevalence in a given season, it’s not to be...

Pumping Up Trees in the Face of Disease

Foliar nutrition takes on enhanced role in the battle against HLB Since HLB (Huanglongbing) was first identified in Florida in 2005, its spread has been rapid across all citrus-producing counties in the state. Today, the disease is entrenched with ever-increasing rates of infection as scientists seek solutions for one of the citrus industry’s biggest threats. “The infection rates are high,” says Ryan Atwood, product representative for Winter-Park, FL-based KeyPlex. “We are getting pretty close to 100% infection rates in some of the worst-hit areas. It varies and is not as bad in the northern producing areas, but it is...

Save Your Citrus: Is it Nutrients or HLB?

Your trees are trying to tell you something. Learn how to interpret the signs. For success in citrus production, growers need to be in tune with what’s going on in their grove. When something doesn’t appear right — whether it’s one tree or an entire block — some kind of action is needed. Of course, action means time, and time means money. Making the wrong decision in this case can cost you your crop and potentially a whole lot more. When trying to correctly identify if a tree is sick or just lacking the proper nutrients, Ryan Atwood, product...

Nutrient Functions in Citrus

Micronutrients play a critical role in citrus production and tree health While a lot of attention has been focused on foliar nutrition as a means of promoting tree health in the face of HLB, many growers are learning that application of key micronutrients makes sense even if by some miracle the disease disappeared. In what may be the irony of all ironies, some farmers have even claimed the onset of HLB has made them even better growers. “To paraphrase a quote I’ve heard from some growers is, ‘Yes, HLB is a bad deal, but in the process we’ve really...

Managing Calcareous Soils for Citrus Production

Without effective fertility management, citrus yields will be reduced on alkaline soil types. Most calcareous soil situations are created during the bedding process on flatwoods soils. A typical flatwoods soil has an alkaline, loamy horizon (layer) about 40 inches down from the soil surface. If this layer is closer to the soil surface than 40 inches, then much of this material is brought to the soil surface from the furrow when the beds are formed with the grader. Calcareous situations also can be manufactured when drainage ditches are dug and the subsoil is spread out by rows along the...

Nitrogen Management for Commercial Citrus Production

Proper management of nitrogen is an essential element to successful citrus production. While growers seek every unique advantage they can to produce superior crops over their competition, often there are unavoidable common ties – even among the most sophisticated proprietary plant nutrition programs. Case in point, nitrogen is a key ingredient in most every plant food recipe. As well it should be given the element’s impact across the vast growth spectrum. Micro-managing this macronutrient is necessary, as there is a fine line between the benefits nitrogen can bring to a crop and the possible damage it can inflict due...

Evaluation of KeyPlex 350 OR for PFD Control on Navel Orange

This experiment was established on mature navel orange trees in a randomized complete block design using double tree plots and five replications. Two flower clusters with 10-20 blossoms at the pinhead stage were selected per tree and flagged for future reference. KeyPlex 350 OR was applied at 3 quarts per 125 gallons of spray on March 3 and again on March 8, 2008. Application was made using a single nozzle handgun at 100 psi with the entire canopy sprayed to runoff. Topsin M WSB at 2 pounds per 125 gallons was also applied on March 8, 2008, as a...
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