The principal injurious species to commercially-grown flue-cured tobacco in Nova Scotia was the dark-sided cutworm, Euxoa messoria Harr. A trace of the black cutworm, Agrotis ipsilon Hufn., was found in one field. The variegated cutworm, Peridroma saucia Hbn., caused minor damage in September. Other species reared from field-collected larvae, and bait and light trap catches, included: yellow-headed cutworm, Apamea amputatrix Fitch; armyworm, Pseudaletia unipuncta Haw.; Amphipyra tragopoginis L.; W-marked cutworm, Spaelotis clandestina Harr.; and the glassy cutworm, Crymodes devastator Brace.
Cutworm larvae damaged young tobacco plants during June through mid-July. The largest infestation encountered during 1971, near the margin of a field, killed 5% and injured 20% of the young plants. Infestations in other fields injured 1 to 3% of the plants, with higher incidences near the borders. A seasonal total of 0.024 cutworm larva injured 0.24 tobacco plant/m2 and destroyed 5 to 10% of the injured plants in experimental tobacco field plots planted in a 4-year-old rye field.
Tobacco trap crop m2 microplots in a rye field attracted 20 to 50 times as many cutworm larvae and had 25 to 40 more plants injured than comparable areas of an adjoining tobacco field. The largest microplot infestation in six fields tested was 1.8 larvae injuring 7.4 plants. The average microplot infestation of 0.5 larva injured 5.6 plants.