Date of Award:
5-1-1969
Document Type:
Thesis
Degree Name:
Master of Science (MS)
Department:
Biology
Department name when degree awarded
Entomology
Committee Chair(s)
B. Austin Haws
Committee
B. Austin Haws
Committee
Keith R. Allred
Committee
Le Grande C. Ellis
Abstract
The objectives of this study were: (1) to develop methods of screening alfalfas for weevil damage, (2) to survey available alfalfas for susceptible and non-susceptible breeding lines, and (3) to determine if certain characteristics of alfalfas are related to the number of alfalfa weevil larvae present. Five methods of screening alfalfas were studied. Oviposition damage was determined by removing a given number of stems to the laboratory where the number of oviposition holes per stem were tabulated. Feeding damage was determined by rating each alfalfa plant according to a scale that ranked alfalfa weevil feeding damage to individual plants. Larval populations were determined by either shaking a given number of stems into a container or by removing the whole plant or a given number of stems to the laboratory and tabulating the number of larvae. Leaflet damage was determined by removing a given number of stems to the laboratory where feeding damage to leaflets was determined using a rating system. The preference of larvae for different alfalfas was tested in the laboratory. Five hundred and ninety different alfalfas were screened for resistance to the alfalfa weevil in this study. All alfalfas showed a degree of susceptibility but clones N-383, L-85 Ariz. and 56-10-14 Ariz. appear to be possible sources of resistance lines. Among the alfalfas showing a high degree of susceptibility no trend could be established when all screening tests were compared. No correlation could be shown between larval population and the agronomic characteristics of the alfalfas measured in this study.
Recommended Citation
Coons, Lewis B., "Investigations on Alfalfa Weevil Damage to Selected Alfalfas" (1969). Biology. 357.
https://digitalcommons.usu.edu/etd_biology/357
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