Tree and Nut Crops

Tree & Nut Crops

May 2019

Huanglongbing of Citrus

Publication (PDF, 1.24MB)

Authors: Jiahuai Hu and Glenn Wright

Huanglongbing (Chinese for yellow dragon disease or yellow shoot disease, abbreviated as HLB) also known as citrus greening, is a lethal, fast-spreading bacterial disease of citrus. HLB is the worst disease of citrus trees worldwide.
Jan 2019

Zinc Management in Arid Region Pecan Orchards

Publication (PDF, 1.2MB)

Authors: Dr. Jim Walworth and Dr. Richard Heerema

Zinc nutrient deficiencies in pecan trees can cause several symptoms. Rosetting caused by shortened internodes, Interveinal chlorosis, and necrosis of young leaves are among them. This article gives some suggestions on how to mange your zinc applications.
Jun 2018

Pecan Bacterial Leaf Scorch

Publication (PDF, 1.21MB)

Authors: Jiahuai Hu

Pecan bacterial leaf scorch (PBLS) is an important and chronic disease that affects pecan in Arizona, as well as other pecan production regions of the United States. This article discusses the disease.
Jun 2018

Phymatotrichopsis Root Rot in Pecan

Publication (PDF, 2.22MB)

Authors: Jiahuai Hu

Phymatotrichopsis root rot (abbreviated as PRR) is commonly referred to as Cotton root rot, Phymatotrichum root rot, Texas root rot, or Ozonium root rot. This pathogen is prevalent in all of major pecan production areas in Arizona.
Jun 2015

Training and Pruning Newly Planted Deciduous Fruit Trees

Publication (PDF, 1.31MB)

Authors: Tom DeGomez

Training and pruning newly-planted deciduous fruit trees is one of the most important steps in developing trees with a strong framework (scaffold branches). Trees with a good framework of branches can support heavy crops without limb breakage and will help to bring the young tree into production at an early age. Selection and arrangement of these branches determines the type of development and growth in later years. The goal of pruning and training is to balance vegetative and fruiting wood growth.
Jun 2015

Citrus Fertilization Chart for Arizona

Publication (PDF, 433KB)

Authors: Glenn Wright

Provides a chart to help one estimate how much fertilizer a citrus tree needs based off of the nitrogen content of the fertilizer.
Feb 2015

Cotton (Texas) Root Rot

Publication (PDF, 707KB)

Authors: Mary Olsen

The most important disease of woody dicotyledonous plants in Arizona is Phymatotrichopsis root rot (Cotton or Texas root rot) caused by a unique and widely distributed soil-borne fungus, Phymatotrichopsis omnivora. This article talks about the diseases distribution, symptoms/signs, biology, identification, sampling, and control.
Oct 2011

Leaf Sampling Guide with Interpretation for Arizona Pecan Orchards

Publication (PDF, 1.25MB)

Authors: James L. Walworth, Andrew P. Pond, Michael W. Kilby

Leaf analysis is an excellent tool for evaluating the current nutritional status of pecan trees and for diagnosing nutrient disorders. This Article outlines how the process is conducted.
Aug 2011

Diseases of Citrus in Arizona

Publication (PDF, 3.99MB)

Authors: Mary Olsen, Mike Matheron, Mike McClure and Zhongguo Xiong

Many diseases of citrus have been described world wide and have colorful and descriptive names such as: blue mold, green mold, gray mold, pink mold, pink nose, brown rot, black spot, black rot, black pit, yellow vein, yellow spot, rubbery wood, lumpy rind, curly leaf, corky bark, slow decline, spreading decline, and stubborn. This article secribes some of the diseases common to Arizona
Jan 2011

Verticillium Wilt

Publication (PDF, 3.11MB)

Authors: Mary W. Olsen

Verticillium wilt may cause wilting of all or only parts of plants. Leaves become mottled or chlorotic and turn brown, often in interveinal parts of the leaves only. This article covers signs/symptoms, environmental conditions, the disease, and control.
Apr 2009

Diagnosing Home Citrus Problems

Publication (PDF, 8.47MB)

Authors: John Begeman, Glenn Wright

A collection of pictures that can be used to help diagnose citrus problems. This includes diseases, stresses and pest injury.
Jul 2008

Pruning Citrus

Publication (PDF, 1.96MB)

Authors: Glenn C. Wright, Jack Kelly

Pruning is a common task necessary for best production of many common fruit trees. Most types of deciduous trees are pruned to invigorate the tree, to improve branch configuration, and thus make branches less likely to split under a heavy crop, to improve fruit quality, and/or to reduce the crop load which will improve the potential size of individual fruits.
Feb 2000

Irrigating Citrus Trees

Publication (PDF, 178KB)

Authors: Irrigating Citrus Trees

Water is essential for citrus trees.This article discusses some of the symptoms of stresses caused by lack of water and gives suggestions on how to estimate and time water applications on citrus trees.
May 1991

Nitrogen Management Guide for Pistachios

Publication (PDF, 107KB)

Authors: Thomas A. Doerge, Robert L. Roth, Bryant R. Gardner

Mature pistachio trees are moderately heavy users of nitrogen. The pronounced alternate bearing cycles observed in pistachios have the greatest influence on the optimum Nitrogen fertilizer rate to use.
May 1991

Nitrogen Management Guide for Pecans

Publication (PDF, 205KB)

Authors: Thomas A. Doerge, Robert L. Roth, Bryant R. Gardner

Mature pecan trees are heavy users of nitrogen. Under most Arizona conditions 150 to 200 lbs N per acre are required for optimum nut production.
May 1991

Nitrogen Management Guide for Apples

Publication (PDF, 183KB)

Authors: Thomas A. Doerge, Robert L. Roth, Bryant R. Gardner

Adequate supplies of nitrogen are needed to promote rapid growth and development of young nonbearing trees.
May 1991

Nitrogen Management Guide for Citrus

Publication (PDF, 136KB)

Authors: Thomas A. Doerge, Robert L. Roth, Bryant R. Gardner

The level of nitrogen fertility has more influence on the growth and yield of Citrus than any other single plant nutrient because it is the nutrient most often deficient in Arizona soils.

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