Integrating biological control into management decisions for whitefly in cotton

Bemisia tabaci (Middle East-Asia Minor 1) is a key pest in Arizona cotton that can reduce lint quality and yield. Whiteflies are currently managed within an IPM framework that includes frequent sampling, use of economic thresholds and selective chemistry that promotes conservation biological control. This program has contributed to large reductions in insecticide use and higher returns for producers; however, decision-making framework for guiding insecticide use is based on pest levels only. Biological control by a suite of arthropod natural enemies can act to regulate whitefly populations under certain circumstances, avoiding or further delaying the need for insecticidal inputs. Our objectives were to incorporate biological control into the decision-making process for whitefly management. Two years of field trials were carried out to explore the dynamic relationships between generalist predators and whiteflies through experimental manipulation of their populations. Candidate thresholds based on predator:prey ratios were identified and are being tested in validation / demonstration studies in comparison to pest-only thresholds. These new biological control based thresholds should potentially delay and/or reduce insecticide applications while providing effective whitefly management. The validation of simple to use sampling plans and extensive education and outreach activities are planned to promote adoption. Despite early hopes (Stern et al. 1959), there are few working examples today worldwide of explicit incorporation of biological control in the insect pest management decision-making framework that have been adopted and used by growers. Our effort focuses on usability, validation, and demonstration in commercial settings and advances this fundamental element of “integrated control”.