A Relationship Between Plant Height of Alfalfa and the Rate of Alfalfa Weevil Larval Development12

Two studies were conducted in which 131 selected clones of alfalfa were screened for resistance to the larva of Hypera postica (Gyllenhal). There were no significant differences among the 131 clones with regard to the time required for the larva to complete development. Observations made during the tests indicated that larvae were developing more rapidly on taller plants regardless of the clone. Therefore, clonal identity was disregarded and in each test the data from all clones were pooled and analyzed to determine if there was a relationship between plant height and the time required for larval development. The results of both studies showed that length of time required for the larva to complete development decreased as the plant height increased, up to heights of 10–12 em. The authors suggest that the more rapidly growing, taller plants may have superior nutritional quality.