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.
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.
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.
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.
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.
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.
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.