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.
ARIZONA PEST MANAGEMENT CENTER
University of Arizona College of Agriculture and Life Sciences Maricopa Agricultural Center