Nocturnal migrations of cotton insect pests indicated by Doppler radar

Authors: Westbrook, John; Eyster, Ritchie

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/6/2008
Publication Date: 6/1/2003
Citation: Westbrook, J.K., Eyster, R.S. 2003. Nocturnal migrations of cotton insect pests indicated by Doppler radar. Proceedings of the Beltwide Cotton Conference, Memphis, TN, January 6-10, 2003. p. 997-1003.

Interpretive Summary: An outbreak of beet armyworms and other insect pests devastated cotton production in the Lower Rio Grande Valley of Texas in 1995. Major infestations occurred later in the year in other cotton production areas of Texas and Oklahoma, but it is unclear if migratory flights of insect pests contributed to subsequent area-wide infestations. We evaluated the capability of a National Weather Service Doppler radar to monitor migratory flights of insect pests from severely infested cotton production areas. Discrete (source) areas of maximum radar reflectivity appeared approximately a half-hour after sunset and displaced downwind. The source areas were located near major infestations of beet armyworms, loopers, bollworms, and budworms in cotton in the Lower Rio Grande Valley. We envision that, at a minimum, National Weather Service Doppler radar data can be coupled with atmospheric data to estimate the timing and intensity of insect pest migrations for use in crop advisories.

Technical Abstract: An outbreak of beet armyworms and other lepidopterous pests devastated cotton production in the Lower Rio Grande Valley of Texas in 1995. Major infestations occurred later in the year at San Angelo and other cotton production areas in Texas and Oklahoma, but there have been no reports that connected the infestations by these migratory pests. The objective of this study was to evaluate the capability of a WSR-88D Doppler radar to locate and monitor pest emigration from severely infested areas. We found that discrete (source) areas of maximum radar reflectivity (13.5 to 16.5 dBZ) appeared approximately 0.5 h after sunset, and displaced downwind. The source areas were located in the vicinity of major infestations in cotton by beet armyworms, loopers, and bollworms/budworms reported in Willacy County, TX. We envision that, at a minimum, the WSR-88D Doppler radar data can be coupled with atmospheric data to estimate the timing and intensity of dispersal of migrating insect pests for use in crop advisories.