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Epizootiology of virus diseases in three lepidopterous insect species of alfalfa
Author(s) -
Tanada Y.,
Omi Esther M.
Publication year - 1974
Publication title -
population ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 59
eISSN - 1438-390X
pISSN - 1438-3896
DOI - 10.1007/bf02514080
Subject(s) - biology , exigua , nuclear polyhedrosis virus , autographa californica , epizootiology , beet armyworm , virus , insect , host (biology) , spodoptera , virology , botany , ecology , biochemistry , gene , recombinant dna
Summary The incidence of virus infections in three lepidopterous insect species was studied from 1965 to 1968 in alfalfa fields in California. The insects were the alfalfa caterpillar, Colias eurytheme ; the beet armyworm, Spodoptera exigua ; and the alfalfa looper, Autographa californica . In C. eurytheme , the major virus was a nuclear polyhedrosis virus (NPV); in S. exigua , a granulosis virus (GV) and an NPV; in A. californica , a GV. Virus epizootics did not develop in very high densities of C. eurytheme . Virus epizootics occurred in low host densities of the three insect species, especially in populations of A. californica . The virus acted as a density‐dependent factor in the regulation of the populations of S. exigua and A. californica . Temperature, humidity and rainfall had no marked effect on the incidence of virus infections.