Arnold Schumann

Citrus Nutrition Management Practices

Jamie D. Burrow, Tripti Vashisth, Mongi Zekri, Stephen H. Futch, and Arnold Schumann

This document is HS1292, one of a series of the Horticultural Sciences Department, UF/IFAS Extension. Original publication date May 2017.

Management of Citrus Tree Canopies for Fresh-Fruit Production

Andrew Krajewski, Arnold Schumann, Tim Ebert, Chris Oswalt, Rhuanito S. Ferrarezi, and Laura Waldo

Nutrition of Florida Citrus Trees, 3 Edition: Chapter 11. Special Situations

Thomas A. Obreza, Brian J. Boman, Mongi Zekri, Stephen H. Futch, Lawrence R. Parsons, James J. Ferguson, Rhuanito Ferrarezi, and Arnold Schumann

This publication is part of SL253, Nutrition of Florida Citrus Trees, 3rd Edition. For references, a glossary, and appendices, please refer to the full document at https://edis.ifas.ufl.edu/ss478.

Soil Sampling Procedures

Davie Kadyampakeni, Kelly Morgan, Arnold Schumann, and Rhuanito S. Ferrarezi

Nutrition of Florida Citrus Trees, 3 Edition: Chapter 5. Precision Agriculture for Citrus Nutrient Management

Arnold W. Schumann and Edward A. Hanlon

Increasing Efficiency and Reducing Costs of Citrus Nutritional Programs

Mongi Zekri, Thomas Obreza, and Arnold Schumann

Soil and Leaf Tissue Testing for Commercial Citrus Production

Thomas A. Obreza, Mongi Zekri, Edward A. Hanlon, Kelly Morgan, Arnold Schumann, and Robert Rouse

2025–2026 Florida Citrus Production Guide: Citrus under Protective Screen (CUPS) Production Systems

Arnold W. Schumann, Ariel Singerman, Mark A. Ritenour, Jawwad Qureshi, and Fernando Alferez

2025–2026 Florida Citrus Production Guide

2025–2026 Florida Citrus Production Guide: Nutrition Management for Citrus Trees

Kelly T. Morgan, Davie M. Kadyampakeni, Mongi Zekri, Arnold W. Schumann, Tripti Vashisth, Muhammad A. Shahid, and Thomas A. Obreza

2025–2026 Florida Citrus Production Guide

Computer Tools for Diagnosing Citrus Leaf Symptoms (Part 2): Smartphone Apps for Expert Diagnosis of Citrus Leaf Symptoms

Arnold Schumann, Laura Waldo, Perseveranca Mungofa, and Chris Oswalt

A UF/IFAS numbered peer reviewed Fact Sheet. in support of UF/IFAS Extension program: Plant Systems

A Non-Technical Introduction to Electropenetrography and Its Application with Asian Citrus Psyllid as an Example

T. A. Ebert, A. W. Schumann, and A. J. Krajewski

Protecting plants by targeting insect vectors of pathogenic organisms requires an intimate understanding of the biology of the insect, the pathogen, and the plant host at a spatial scale relevant to the insect. Observing insect feeding is difficult because insect mouthparts are small, and many insects insert their mouthparts deep inside plants, where we cannot see them. Electropenetrography (EPG) is the only technique that overcomes these problems. Using EPG, we can understand host-insect relationships, pesticide action, and the role of non-hosts. EPG can address ecological questions like "How do insects survive long migrations over regions devoid of known host plants?" It can also address applied questions: "Will the pest feed on my new cultivar?" This light introduction to an underused key technology focuses on a single example insect vector, the Asian citrus psyllid, but EPG has great potential to improve pest management efforts for many crops and insect vectors.

Fertigation for Citrus Trees

Mongi Zekri, Arnold Schumann, Tripti Vashisth, Davie Kadyampakeni, Kelly Morgan, Brian Boman, and Tom Obreza

A UF/IFAS numbered Fact Sheet. Published by Plant Systems

2025–2026 Florida Citrus Production Guide: Fertilizer Application Methods

Mongi Zekri, Arnold W. Schumann, Tripti Vashisth, Davie M. Kadyampakeni, Kelly T. Morgan, Brian Boman, Muhammad A. Shahid, and Thomas A. Obreza

2025–2026 Florida Citrus Production Guide

A Close-up Look at Screens for Excluding Asian Citrus Psyllids

Timothy A. Ebert, Arnold W. Schumann, Laura Waldo, Daniel Stanton, and Philippe Rolshausen

Building a physical barrier around citrus trees or groves can prevent contact between trees and Asian citrus psyllids, the carrier of the pathogen that causes huanglongbing. This new 4-page article is for growers, scientists, and industries that are interested in this approach to protect citrus from huanglongbing. Written by Timothy A. Ebert, Arnold W. Schumann, Laura Waldo, Daniel Stanton, and Philippe Rolshausen, and published by the UF/IFAS Department of Soil and Water Sciences.

Managing Fruit Splitting in Florida Citrus

Andrew Krajewski, Timothy Ebert, Arnold Schumann, and Laura Waldo

Sometimes, the fruit on citrus trees will split open, making the fruit unmarketable; splitting can aid fungal and insect pests that subsequently damage fruit. A physiological disorder, pre-harvest fruit splitting begins with nutrient imbalances at flowering. Nutrient deficiencies weaken the rind, causing it to crack if interior parts of the fruit expand too quickly. Symptoms are only visible after it is too late to avoid the problem, but mitigation is still possible. Our goal is to define the problem and suggest management tactics for growers and Extension personnel to avoid or mitigate pre-harvest fruit splitting.

2025–2026 Florida Citrus Production Guide: Irrigation Management of Citrus Trees

Davie M. Kadyampakeni, Kelly T. Morgan, Mongi Zekri, Arnold W. Schumann, Sandra Guzmán, Fernando Alferez, Muhammad A. Shahid, and Thomas A. Obreza

2025–2026 Florida Citrus Production Guide