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United States Department of Agriculture

Agricultural Research Service

Title: Occurrence of Beet Armyworm Moths in Cotton-Growing Areas of the Lower Mississippi River Delta As Indicated by Numbers Caught in Pheromone Traps in 1994

Authors
item Hendricks D E,
item Hubbard D W,
item Hardee D D,

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 1, 1995
Publication Date: N/A

Interpretive Summary: A survey of beet armyworm moths was conducted in 1994 to determine their presence and developmental rate throughout the growing season in the lower Mississippi River delta region. Fifty-four traps (Universal Moth Traps) were installed from near Skene, MS in southern Bolivar Co. southward to Onward in Sharkey Co. Traps were set ca. 2.1 km apart and baited with beet armyworm sex pheromone that lured male moths to the traps. Traps were checked and moths counted twice each week from April 7 to Dec. 30. Wings on a majority of moths caught from April 7 to June 30 were covered with nearly a full compliment of scales indicating that these moths did not fly great distances before they were captured. These moths could have emerged from pupae that overwintered in the soil of fields or ditches near the traps. Numbers of moths captured in April were relatively low and ranged from 0.13 moths/trap/night on April 10 to 1.6 moths on April 28, also indicating that a resident population had survived the winter. From July 1 to Nov. 1, there were four distinct peaks in numbers of moths captured, and these peaks were separated by 28-32 d. Highest numbers of moths were caught on Oct. 3 with 400/trap/night. Growth of cotton plants in 1994 preceded the rate of cotton development in 1993 by about 2 wks. In 1994, bolls were set and matured before the greatest numbers of beet armyworms appeared in the fields, and the crop escaped major economic damage by this insect. The skewed shape of a peak graphed for moths captured from July 29 to Aug. 9 indicated that vast numbers of these moths may have been carried from the south to the delta region by storm fronts and rains that occurred during the least 2 wks inJuly.

Technical Abstract: A survey of beet armyworm adults was conducted in the west-central delta region of Mississippi to determine their abundance from April to November, 1994. Fifty-four traps were installed in a line 122 km long from near Skene, Miss. in Bolivar Co. southward to Onward in Sharkey Co. Traps were set 2.1 km apart along the trapline, baited with sex pheromone to lure male moths to the traps, and checked for moth captures twice each week. Wings on a majority of moths caught from April 7 to June 30 were covered with nearly a full compliment of scales indicating that these moths did not fly great distances before they were captured. They may have emerged from pupae that overwintered in soil of local areas in Bolivar or Washington Co. Catches of moths in April were relatively low and ranged from 0.13 to 1.6/trap/night. These low capture levels also indicated that beet armyworms had survived the winter as a local population. From July 1 to Nov. 1, there were four distinct peaks in numbers of moths caught, and these peaks were separated by 28 to 32 days. Highest numbers of moths were caught on Oct. 3 with 400/trap/night. Captures were sharply reduced on nights in April, Sept., Oct., and Nov. when air temperatures dropped below 48oF. In 1994, cotton bolls developed earlier than in 1993 and matured and hardened before great numbers of beet armyworms appeared in the fields. Hence, in 1994 cotton escaped serious economic damage by this insect. The shape of a peak in moths catches graphed for July 29 to Aug. 9, compared with sequences in rainfall, indicated that many moths may have been carried to the region by storm fronts from the south and deposited in cotton fields during rain storms.

Last Modified: 10/25/2014
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