Alfalfa varieties differ in fall dormancy, defined asgrowth during the fall. Nondormant alfalfa varieties are usually planted in mild winter areas for their ability to grow in the fall. Nondormant, very nondormant, and extremely nondormant alfalfa varieties (fall dormancy class 8, 9, and 10) are adapted to elevations below 4000 feet in Arizona.
Authors: Peter C. Ellsworth, Naomi Pier, Alfred J. Fournier, Steven E. Naranjo, Timothy Vandervoet
New research has identified critical levels of predators that impact economic spray decisions for whiteflies. By working with the beneficials found naturally within a field, reliance on chemical controls could effectively be reduced.
Interactions Between Insects & Weeds in Desert Crops - July 2018
There is a positive correlation between weeds and insects. This article describes the relationship between weed management and insects. It details how weeds can be a refuge for beneficial insects and how they can also act as a reservoir for insect pests. The impact that weeds have on insecticide application is also discussed.
Variety selection is one of the most important decisions a grower will make contributing to the success of a cotton crop. It is critical, that a grower have as much information as possible in order to make an informed decision regarding variety selection.
Recent outbreaks of cowpea aphid in alfalfa are more than a local phenomena. Large populations of cowpea aphids have been reported throughout Arizona. The reason behind these outbreaks are unknown. This article hopes to bring some insight by discussing the cowpea aphid, the damage it causes, and suggestions on controlling it.
This article contains a chart of non dormant alfalfa varieties for Arizona. Suggestions for determining an appropriate fall dormancy class, identifying potential pest problems, yield, and salt tolerance are all discussed.
Estimating the Vegetative/Reproductive Balance in Cotton Growth
A healthy, well-developed cotton plant that is capable of high yield requires a strong root system, mainstem structure, sufficient leaves, and numerous fruiting branches to support a good boll load. Too small a vegetative structure on the plant results in reduced yield potential, and too much vegetative development, which is usually done at the expense of fruit set and yield.
The approaches and techniques used to produce a cotton crop in Arizona can vary to some degree from county to county, or from farm to farm. However, one of the objectives that has become increasingly common across Arizona is that of achieving earliness with a crop.
Predicting and Mitigating Resistance Development in Whiteflies
Authors: Naomi Pier, Lydia Brown, Peter Ellsworth, John Palumbo, Yves Carriere, Al Fournier (University of Arizona); Steve Castle (USDA), Nilima Prabhaker (UC-R)
Insecticidal resistance in whiteflies is a real problem, threatening economic and effective pest control. Research is being done on whitefly resistances to currently used chemical controls and the potential of usage patterns to contribute to the development of these resistances. Effective resistance mitigation begins with the application of the first principles of resistance management.
Soil Management and Soil Testing for Irrigated Cotton Production
Whenever studying cotton, it is a natural tendency to focus on the above ground portions of the plant. However, an equally important part of the plant is the root system, The soil is a focal point of any farming operation.
Three maturity groupings are often used to classify cotton varieties, consisting of: 1) short season or more determinate plants, 2) medium season varieties, and 3) long or full season varieties which are more indeterminate in nature. Classification of cotton varieties into one of these three categories is not necessarily straightforward in all cases. In fact, it easily can become a process of “splitting hairs” when making maturity grouping designations for cotton varieties. Nevertheless, maturity designations are commonly assigned to most commercially available varieties, which can effect selection and management.
This bulletin deals with the physiology of cotton defoliation and attempts to describe what conditions must exist inside the plant in order for defoliation to occur. It is important to understand the basic physiological processes involved in order for best crop management practices to accomplish a successful defoliation.
After stand establishment, the next critical stage in the development of a cotton crop is the initiation of the first squares, or floral buds, which could develop into the plants’ first boll. This is an important step for a cotton crop and one which is usually followed closely by the attentive farmer.
There are several factors which are important to consider in managing defoliation. Factors such as plant-water relations, Nitrogen (N) fertility status, the extent of honeydew deposits on the leaves from insects such as the sweet potato whitefly or aphids, and weather conditions following the defoliant application are all important in terms of the final defoliation results.
Soil Fertility and Soil Testing Guideline for Arizona Cotton
According to all available evidence, there are 20 total nutrients necessary for complete plant growth and development. Not all are required for all plants, but all have been found to be essential to some.
Nitrogen is the primary fertilizer nutrient required by wheat and barley. This article describes the optimum nitrogen fertilizer rate, nitrogen fertilizer scheduling, and how to boost grain protein content.
Wheat and barley use about 2 ft of water in Arizona, but 3 to 3.5 ft of applied water is often required with surface flood irrigation due inefficiencies in the irrigation system. Some suggestion on how to irrigate your small grains are made, including when and how much.
Small grain growth and development can be divided into several major and minor stages. This article discusses those stages and what to look as the crop develops. A chart also details the timing of management operations during crop development.
Planting at the optimum time is probably the most important cultural practice in producing high small grain yields. Wheat and barley crops that are planted too early or too late have lower yield potential no matter how they are grown after planting. Some suggestions on planting dates are outlined in this article.
Small grains are planted for a variety of reasons, but their rotational benefit makes them a popular crop all over the world and influences the way they are planted. One of the major benefits of small grains as rotational crops is that they cover the soil and suppress weeds
Karnal bunt is a disease of wheat, durum, and triticale caused by the fungal pathogen Tilletia indica Mitra. Karnal bunt was first reported in India in 1931. This article discusses it's cycle, symptoms, and suggestions on how to control it.
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.
Genetic Diversity and Fungicide Sensitivity of Phymatotrichopsis omnivora
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.
Small Grains Variety Evaluation at Arizona City, Maricopa and Yuma
Small grain varieties are evaluated each year by University of Arizona personnel. The purpose of these tests is to characterize varieties in terms of yield and other attributes. This article describes the procedure.
Research Report Effect of Planting Date on Wheat Yield in Yuma
Planting dates are known to affect wheat yields. Previous research has shown that the optimum planting date in Yuma is December 15 to January 15. This research paper tested six different planting dates with a wide range of varieties of wheat.
Methods of Measuring for Irrigation Scheduling - When
Proper irrigation management requires that growers assess their irrigation needs by taking measurements of various physical parameters. Some use sophisticated equipment while others use tried and true common sense approaches. Whichever method used, each has merits and limitations. In developing any irrigation management strategy, two questions are common: “When do I irrigate?” and “How much do I apply?” This bulletin deals with the WHEN.
Determination of optimal planting configuration of low input and organic barley and wheat production in Arizona
Markets for organic barley and wheat are expanding. A major problem growing organic barley and wheat is controlling the weeds. This paper outlines a study of growing organic barley documenting the weed pressures.
Sensor-based management of Nitrogen of irrigated durum wheat in Arizona
Authors: Pedro Andrade-Sanchez and Michael J. Ottman
It can be difficult to accurately apply the proper amount of nutrients to wheat due to their varying sizes and densities. Current field equipment can already vary the rate of fertilizer dispersal, but it needs to be controlled by an algorithm. An algorithm is being developed for that purpose.
Alfalfa is an important crop grown in Arizona with approximately 250,000 acres in production in 2011 and 2012 and 260,000 acres for 2013. As alfalfa stands age, they can thing and decline in plant density. This article takes a look at renovating alfalfa stands in Arizona.
“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.
Recommendations for Growing Standard-Height Wheat Varieties in Arizona
Until the introduction of semi-dwarf wheat in the late 1960s, wheat varieties were typically one and a half to two times their current height. Most "standard height" wheat varieties are adapted to lower-input conditions, and cannot tolerate high-fertility environments without lodging. Planting date, seeding rate, nitrogen rate, phosphorus rate, and irrigation are discussed in this article.
Forage sorghums are warm-season, annual grasses that have the potential to produce large amounts of nutritious forage during summer months, especially in lower-elevation deserts, like central Arizona. If managed properly , sorghum can be used as supplemental feed during times of inadequate forage production or can be used as an emergency , late-planted crop to replace a primary crop that has been damaged by wind, hail or drought early in the growing season.
Stink bugs in cotton, alfalfa, and other Arizona crops
In Arizona, we have many species of stink bugs; the species pictured above are encountered in cotton, alfalfa, and other crops. Some are occasional or potential pests of cotton. In the article the Brown Stink Bug (BSB), Eushistus servus, is discussed which has been a pest of cotton, especially in the past few years.
Operation of Yield Monitors in Central Arizona: Grains and Cotton
Yield maps can be an important management tool to quantify the impact of management practices including water, fertility, pest control, variety selection, etc. Yield monitoring technology provides farm managers with information to improve input utilization, therefore many guidelines for their use are available online, including university cooperative extension bulletins for grain crops, and cotton.
Insect Management on Desert Produce Crops: Western Flower Thrips 2013
Western flower thrips are major pests to lettuces, cabbage, and spinach because of the damage they cause to these plants. This article describes their development, Economic Damage, and suggestions for their management.
New technologies have enabled cotton growers to reduce their spray applications significantly while achieving among highest cotton yields worldwide. Arizona now produces the highest yielding cotton in the world, well over 1,500 pounds of fiber per acre, far exceeding the U.S. national average of about 750 pounds per acre. These technologies also help growers implement more ecologically based, sustainable IPM programs and become less dependent on broadly toxic insecticides.
Guayule (why-YOU-lee) is a woody plant that thrives in the deserts of the U.S. Southwest and MExico. New Clean Technologies make it possible to extract natural rubber, latex, ethanol, non-toxic adhesives and other specialty chemicals from guayule.
Authors: Peter C. Ellsworth, Lydia Brown (University of Arizona) & Steven Naranjo (USDA-ARS)
Using selective chemistries is safer for the user and environment. This includes the beneficial predators found within fields that are important for controlling pests such as whiteflies and Lygus bugs. Selective chemistries are an important component of Arizona’s insect cotton IPM program. Current research is being conducted on the newest chemistries to determine their selectivity towards non-target organisms, such as beneficials.
An Introduction to the Use of Reference Strips for N Management in Durum Wheat
A proper application of nitrogen fertilizer can be somewhat difficult for Arizona growers due to a varying amount of nitrogen needed from year to year. This article explains the use of reference strips for assessing the proper amount of nitrogen fertilizer needed that year.
This document has a quick breakdown of some of the most important factors to consider when irrigating small grains. Topics such as seasonal water use, the first irrigation, last irrigation, and soil water balance methods.
Determining the Amount of Irrigation Water Applied to a Field
Critical to any irrigation management approach is an accurate estimate of the amount of water applied to a field. Estimating the amount of water applied to a field or to a set is fairly easy for surface systems.
Authors: Guangyao (Sam) Wang, Shawna Loper, Mike Ottman, and James Walworth
Pre-plant soil sampling is critical for profitable crop production. Soil analysis can help decide pre-plant fertilizer application. Generally only nitrogen and phosphorus fertilizer applications are ever needed in Arizona.
Wheat and barley crops are susceptible to lodging, the bending over of the stems near the ground level. Suggestions on how to control this are outlined in this article. Herbicides, fungicides, and cultural/environmental factors.
Minimum tillage for wheat following winter vegetables
Authors: Kurt Nolte, Mike Ottman, Trent Teegerstrom and Guangyao (Sam) Wang
Wheat is typically grown after cotton or other field crops in most of Arizona except for Yuma County where wheat is planted after winter vegetables. This article describes the benefits of utilizing the minimum tillage threshold when planting wheat after other crops.
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.
Alfalfa Weed Control in the Low Deserts of Arizona
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.
Weed Control for Wheat and Barley in the Low Deserts of Arizona
Although wheat and barley are vigorous crops that rapidly cover the soil surface and often out-compete weeds, weeds can still become a problem with certain cultural practices. This article gives some suggestions on the usage of herbicides when they become necessary.
Cross-commodity Guidelines for Neonicotinoid Insecticides in Arizona
Authors: John C. Palumbo, Peter C. Ellsworth, Timothy J. Dennehy, Robert L. Nichols
This document outlines some of the guidlines for Neonicotinoids, which were relatively new at the time. The plans within the document aim to help keep Neonicotinoids as a cost efficient and effective form of whitefly management for the future.
Due to worldwide shortages of non-dormant alfalfa seed, production opportunities and acreage have increased recently in central Arizona. This article gives some suggestions regarding growing alfalfa for seed in Arizona.
Beet armyworm (Spodoptera exigua) caterpillars are smooth skinned with few or no hairs on the body, may be olive green to almost black in color down the middle of the back, and have a yellow stripe on each side of the body. This publication details the Beet Armyworm. It's description, biology, damages it causes, and methods of controlling it are discussed.
The first sign of a potential alfalfa caterpillar (Colias eurytheme) outbreak is the influx of large numbers of yellow or white butterflies in late spring or early summer. This article discusses their biology, the damages they cause, types of control, and when to treat for them.
Aphids feed in groups, often on the growing tips of plants. This article describes the complex of Aphids that can be found on alfalfa and discusses damages, monitoring, control, and when to treat for them.
Solum barley was released in 1992 for grain or forage production under reduced water use conditions. Solum barley was developed over the course of 18 years with low input and reduced water usage in mind. This article describes some of its history, uses, planting dates, seeding rates, and characteristics.
Establishing irrigated pasture at 4,000- to 6,000-foot elevations in Arizona
Authors: Deborah Young, Bill Frost, Mike Schneider
Irrigated pasture can provide forage for livestock, be useful during breeding and calving time, serve as an exercise area for horses, and conserve and improve soil and provide an alternative to rangeland. This article discussing establishing a pasture at elevations in Arizona between 4,000 and 6,000 feet.
Diseases and Nutritional Disorders of Wheat, Barley, and Oats
Authors: Richard Hine, Mike Ottman, and Thomas Doerge
The cultivation of wheat, barley, and oats has been around for a long time. There have been many different types of diseases that can attack these crops. This article talks about the diseases that are important to Arizona growers and discusses their symptoms.
Authors: Thomas A. Doerge, Robert L. Roth, Bryant R. Gardner
Nitrogen applications are rarely needed in alfalfa production in Arizona. The primary problems with nitrogen applications to alfalfa are stimulation of weed growth, reduced nodulation, and reduced effectiveness of nodules in "fixing" of nitrogen.
Authors: Richard B. Hine, Michael J. Ottman, and Thomas A. Doerge
Alfalfa is currently grown on approximately 20 percent of the total irrigated crop land in Arizona. This article lists the diseases and nutritional disorders of Alfalfa and gives a lengthy description of each of them.
Oat production has decreased significantly in the United States over the course of the last century. It is still grown as a relatively minor crop in Arizonan agriculture. This article outlines some different varieties and cultural practices in regards to oat production.
Winter Grass Pasture For Low Desert Valleys In Arizona
Crops that can be used for winter grass pasture are barley, oats, wheat and common or tetraploid ryegrasss. Suggestions on planting time, seeding rate, fertilizing, irrigating, harvest and management are discussed.
Forage stands are maintained longer when pastures are properly managed. When a mixture is used, try to maintain each species in its original proportion. This article gives suggestions for maintaining pastures.
ARIZONA PEST MANAGEMENT CENTER
University of Arizona College of Agriculture and Life Sciences Maricopa Agricultural Center