An Alfalfa Disease Calendar

The following calendar provides producers and agricultural professionals with insights that may improve alfalfa production in several ways. First, knowing when to expect certain diseases improves one\u27s ability to diagnose disease problems, which is a fundamental foundation for disease management. The many UK Extension Service publications on alfalfa as well as publications like the Alfalfa Analyst and the Compendium of Alfalfa Diseases, all are useful for diagnosis, but none provides a precise calendar of when to expect activity of alfalfa diseases in Kentucky. An alfalfa disease calendar can also provide occasional insights into timely management practices. For example, being able to recognize when leaf spots are attacking your crop helps aid in making the decision to harvest promptly to avoid losses in yield and quality. As another example, recognizing when Aphanomyces root rot has been active on a farm can help guide a producer to selecting a resistant variety in the future. Finally, having a better understanding of disease dynamics in alfalfa helps the producer and agricultural professional to better develop and customize alfalfa production systems suited to the unique circumstances on each farm. In the calendar below, each month is represented by two sections: early to mid-month and mid- to late month. Each of these can be read as stand-alone sections, without reference to other sections of the calendar. Thus, readers can use only those sections needed for any given time of year

Alfalfa Disease Management

Alfalfa can be a vigorous and productive forage crop for Kentucky farmers. Like all farm crops, however, alfalfa is subject to infectious diseases that can limit forage production. Managing these diseases is an important part of economical alfalfa production

Genetic Engineering and Sustainable Crop Disease Management: Opportunities for Case-by-Case Decision-Making

Genetic engineering (GE) offers an expanding array of strategies for enhancing disease resistance of crop plants in sustainable ways, including the potential for reduced pesticide usage. Certain GE applications involve transgenesis, in some cases creating a metabolic pathway novel to the GE crop. In other cases, only cisgenessis is employed. In yet other cases, engineered genetic changes can be so minimal as to be indistinguishable from natural mutations. Thus, GE crops vary substantially and should be evaluated for risks, benefits, and social considerations on a case-by-case basis. Deployment of GE traits should be with an eye towards long-term sustainability; several options are discussed. Selected risks and concerns of GE are also considered, along with genome editing, a technology that greatly expands the capacity of molecular biologists to make more precise and targeted genetic edits. While GE is merely a suite of tools to supplement other breeding techniques, if wisely used, certain GE tools and applications can contribute to sustainability goals

Managing Alfalfa Diseases

Diseases of alfalfa can limit productivity of this valuable forage crop. Alfalfa diseases can reduce forage yield, reduce forage quality, and decrease stand persistence. The effects of diseases can be dramatic, such as sudden stand loss due to Sclerotinia crown and stem rot. Often, the effects of alfalfa diseases are more subtle but are no less important. For example, alfalfa plants with Phytophthora root rot sometimes regrow slowly after cutting, resulting in a stunted stand showing no other obvious symptoms of disease. Like most crop diseases, alfalfa diseases are most effectively managed by integrating as many control measures as practical. This report will provide an overview of several timely topics relative to alfalfa disease management

A Solution to Some Spring-Seeded Alfalfa Problems

One of the most important assignments I received when I assumed this position in 1990 was to address the question, What is the cause of seeding failure when alfalfa is spring-seeded into soils that remain wet after seeding? Six years of laboratory and field work have finally borne fruit. Based on our research, we can confidently present Kentucky alfalfa producers with three conclusions and a recommendation

Is Ridomil Recommended When Seeding Alfalfa?

Ridomil 2E® fungicide received a federal label in 1991 for control of seedling diseases of alfalfa caused by Pythium and Phytophthora fungi. Pythium fungi are widespread in Kentucky soils but can be controlled with Apron® seed treatment. Phytophthora is less common in Kentucky soils. Where present, Phytophthora can usually be controlled with a combination of resistant varieties and Apron seed treatment. Occasionally, yield increases may be observed using Ridomil in fields highly infested with Phytophthora. However, broadcast applications of Ridomil at seeding are not recommended for most alfalfa fields in Kentucky