Disease - Publications And Resources

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Publications

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.
Jan 2015

Mosquito-borne Diseases and Mosquito IPM

Publication (PDF, 1.28MB)

Authors: Shujuan (Lucy) Li, Dawn Gouge, Shaku Nair, Al Fournier, Ursula Schuch, Kai Umeda, Dave Kopec, Peter Warren

This article discusses several of the most important mosquito diseases in regards to human health. West Nile Virus, St. Louis encephalitis, Dengue fever, and Chikungunya fever are mentioned.
Dec 2014

Pest-o-gram: Whitefly transmitted virus of cucurbits 2014

Publication (PDF, 852KB)

A new and potentially damaging whitefly-transmitted virus of cucurbits was found in the fall of 2014. Symptoms include stunting and leaf yellowing.
Dec 2014

Genetic Diversity and Fungicide Sensitivity of Phymatotrichopsis omnivora

Publication (PDF, 383KB)

Authors: Chitrampalam, P. and Olsen, Mary W.

Cotton root rot, caused by Phymatotrichopsis omnivora, is the most destructive disease of dicotyledonous plants in Arizona. There are no known reliable control methods for this disease, and the difficulty in its management is most often directed at its survival deep in soils and its wide host range. Genetic diversity in P. omnivora and its potential role in disease are unknown. Isolating the fungus and reproducing the disease in the greenhouse or laboratory are problematic, making it difficult to assess the efficacy of potential treatments.
Nov 2014

Pest Abundance on Desert Produce and Melon Crops in 2014

Publication (PDF, 221KB)

This document contains a number of charts and graphs detailing information relating to the abundance of Whitefly, Bagrada bugs, Beet Armyworm, Cabbage Looper, and Corn Earworm. There are also a few figures relaying temperature information.
Jul 2014

2014 Management of Whiteflies and CYSDV on Fall Melons

Publication (PDF, 328KB)

Authors: John C. Palumbo

CYSDV has caused significant reductions in fruit yields in the past, mainly due to the whitefly. This article gives some management guidelines for the whitefly including cultural management and chemical management.
Feb 2014

Diagnosing Nutrient Deficiencies Quick-Reference

Publication (PDF, 429KB)

Authors: Shawna Loper

Nutrient deficiencies can be identified in field through visual observations. However, additional analysis, either plant or soil testing is often necessary to confirm nutrient stress. The following is a quick-reference flow chart that can be used in field to identify potential nutrient deficiencies. Each nutrient has unique deficiency symptoms. Deficiencies will appear in many ways. It can be confused with other plant problems like pathogens or spray damage. But nutrient deficiencies can often be recognized because they tend to form symmetrical patterns, where both sides of leaf or plant parts show the same pattern.
Jan 2014

Summer Slump in Alfalfa

Publication (PDF, 425KB)

Authors: Mike Ottman and Ayman Mostafa

“Summer slump” is a decline in growth of alfalfa usually beginning in July in areas where maximum daily temperature exceeds 100 °F, such as the low elevation deserts of Southwestern U.S. This article discusses some of the causes behind this and potential impacts.
Nov 2013

Pest Abundance on Desert Produce and Melon Crops in 2013

Publication (PDF, 136KB)

This document contains a number of charts and graphs detailing information relating to the abundance of Whitefly, Bagrada bugs, Beet Armyworm, and Cabbage Looper. There are also a few figures relaying temperature information.
Jul 2013

Area wide Incidence of Whiteflies and CYSDV In Fall Melons in Yuma County, 2007-2012

Publication (PDF, 1.77MB)

Authors: John C. Palumbo, Kurt Nolte, Yves Carriere

This is a summary of a recently completed project that was designed to survey the area wide incidence of Bemisia whiteflies and Cucurbit Yellow Stunting Disorder Virus (CYSDV) in commercial melon fields throughout the Yuma Arizona growing region.
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.
Jan 2011

Root-knot Nematode

Publication (PDF, 411KB)

Authors: Mary W. Olsen

Nematodes are microscopic round worms found in many habitats. There are several plant parasitic nematodes that cause problems on landscape and garden plants in Arizona. This article discusses the root-knot nematode, some of the symptoms is causes, disease, and prevention and control.
Aug 2010

Factors Contributing to Development of Salinity Problems in Turf

Publication (PDF, 1.29MB)

Authors: Paul Brown, Jim Walworth

Professional turfgrass managers in many parts of Arizona are confronted with a growing number of management challenges related to excess levels of salinity and/or sodium in soils. The consequences of excess salinity and/or sodium are poor turf performance, reduced water infiltration and the appearance of a new turf disease, rapid blight (Labyrinthula terrestris).
Jun 2009

Growing Grain Sorghum in Arizona

Publication (PDF, 398KB)

Grain sorghum (milo) is a warm season, annual grain crop. It is more resistant to salt, drought, and heat stress than most other crops. Nevertheless, highest yields are obtained when stresses are minimized. This Article give some suggestion on planting, fertilizing, irrigation and other aspects of growing.
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.
Jan 2009

Evaluation of fungicide application programs for management of powdery mildew on muskmelon, 2009

Publication (PDF, 40KB)

Authors: M.E. Matheron, M. Porchas

After a few ears of widespread use, some growers have noticed that some fungicides have become less effective. The objective of this field trial was to evaluate disease control efficiency of various fungicide treatment sequences, utilizing products with different modes of action that are registered for use on melon crops.
Apr 2008

Alfalfa Weed Control in the Low Deserts of Arizona

Publication (PDF, 443KB)

Authors: Barry Ticks and Mike Ottman

Alfalfa is a vigorous crop that is very competitive with weeds. However, chemical weed control is often necessary even in well managed alfalfa since the marketplace has a low tolerance for weeds in alfalfa hay.
Apr 2001

Alfalfa Stem Nematode

Publication (PDF, 30KB)

Authors: Mary Olsen

The alfalfa stem nematode, Ditylenchus dispsaci, is a soilborne plant-parasitic nematode that infects alfalfa. Different races infect other hosts such as onion, oats and strawberries, but the alfalfa race reproduces only on alfalfa in Arizona. This article discusses symptoms, disease cycle, management and identification.
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.

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Presentations

Apr 2019

Alternative Methods of Weed Control

Presentation (PDF, 10.7MB)

Authors: Kai Umeda
Jun 2008

Vegetable Weed Control in the Desert

Presentation (PDF, 5.58MB)

Authors: Barry Tickes

Location Presented: Yuma Agricultural Center
Dec 2003

Management Strategies for Lettuce Drop in Arizona and California

Presentation (PDF, 440KB)

Authors: Barry Pryor
Dec 2003

Onion Disease Management

Presentation (PDF, 441KB)

Authors: Turini, T.

Location Presented: 14th Annual Desert Crops Workshop, Holtville, California.
Sep 2003

Review of Current and Potential Management Tools for Powdery Mildew on Melon Crops

Presentation (PDF, 282KB)

Authors: Matheron, M.

Location Presented: Horticulture Integrated Pest Management Seminar, Pinal County Cooperative Extension Office, Casa Grande, AZ.
Dec 2002

Soilborne Diseases of Melon and Watermelon

Presentation (PDF, 82KB)

Authors: Olsen, M.

Location Presented: Annual Desert Crop Workshop, Yuma, AZ.

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