Cotton aphid emerges as major pest in SJV cotton

• Main Authors: Larry Godfrey, Jay Rosenheim, Peter Goodell
• Format: Article
• Language: English
• Published: University of California Agriculture and Natural Resources 2000-11-01
• Series: California Agriculture
• Online Access: http://calag.ucanr.edu/archive/?article=ca.v054n06p26
• ISSN: 0008-0845; 2160-8091

During the 1990s, the cotton aphid (Aphis gossypii Glover) escalated from an occasional pest to an annual, severe pest of San Joaquin Valley (SJV) cotton. Although the cotton aphid is not a new insect in the SJV, the change in the bionomics of this pest dictated that new research efforts be directed toward its biology, damage thresholds and management. The 1980s saw major shifts in agronomic practices. For example, the introduction of a plant growth regulator allowed growers to promote vigorous plant growth, rather than limiting growth and yield potential through the practice of water and nitrogen stress. Recent field research has shown that applying high rates of nitrogen to cotton plants increases cotton aphid reproductive rates and can create conditions favorable to aphid outbreaks. The new practice of promoting vigorous growth may have created an optimal host plant environment for cotton aphid reproduction and survival. In addition, the shift to using pyrethroids to control other arthropod pests has enhanced the buildup of cotton aphid populations. The severe aphid outbreak during the 1995 cotton growing season served as a focal point to bring the industry together to discuss the status of cotton integrated pest management and to plan future directions. Results of this effort include increased awareness, greater understanding of cotton aphid biology and improved pest management decisions.