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

A person's hand holding a smartphone, taking a picture of a leaf for analysis.

Visual identification of nutrient deficiencies in foliage is an important diagnostic tool for fine-tuning nutrient management of citrus. This new 2-page article describes a new smartphone app that uses a trained neural network to identify disease and pest symptoms on citrus leaves through your phone’s camera. Written by Arnold Schumann, Laura Waldo, Perseveranca Mungofa, and Chris Oswalt, and published by the UF/IFAS Department of Soil and Water Sciences.
https://edis.ifas.ufl.edu/ss691

Citrus Production Guide: Plant Growth Regulators

Citrus groves around Lake Alfred, Florida. Oranges, fruit, trees. UF/IFAS Photo by Tyler Jones.

Plant growth regulators (PGRs) are a tool used to manipulate vegetative and reproductive growth, flowering, and fruit growth and development. PGRs have been successfully used in agriculture for decades to amend plant growth characteristics to maximize yield and grower profit. This new 4-page fact sheet discusses auxins, gibberellins, cytokinins, abscisic acid, ethylene, new classes of plant hormones, use of PGRs for HLB-affected trees, and general considerations for PGR use in Florida citrus groves. Written by Tripti Vashisth, Chris Oswalt, Mongi Zekri, Fernando Alferez, and Jamie D. Burrow, and published by the UF/IFAS Horticultural Sciences Department, February 2018.
http://edis.ifas.ufl.edu/hs1310

Freeze Damage Symptoms and Recovery for Citrus

Figure 6. Fruit drop in citrus after a severe winter freeze. Credits: Mongi Zekri, UF/IFAS
Citrus trees are evergreen, never become fully dormant, and cannot withstand temperatures as low as those tolerated by deciduous trees. But citrus trees can become preconditioned or acclimated to cool air temperatures that occur in late fall and winter. One of the best ways to lessen cold injury and to hasten recovery from cold damage is to maintain healthy trees. This five-page fact sheet discusses the symptoms of freeze damage and ways to help recover trees that have been damaged. Written by Mongi Zekri, Chris Oswalt, Steve Futch, Gary England, Camilly McAvoy, Laurie Hurner, and Parker Platts, and published by the Horticultural Sciences Department.
http://edis.ifas.ufl.edu/hs1250