RECENT RESEARCH ADVANCES ON THE EUROPEAN CORN BORER IN NORTH AMERICA 1,2,3

BIOLOGY AND ECOLOGY Distribution The recorded distribution of the European corn borer, Osttinia nubilalis, has not changed significantly since Brindley & Dicke\u27s review in 1963 (15), except along the southernmost portion of its range. Annual articles presenting the status of the European corn borer (3) indicate that each year the borer spreads into a few previously uninfested counties within known infested states. Sparks & Young (116) made a survey and found 34 of 35 counties infested in southern Georgia and concluded that the borer probably was present in all areas of extensive com production in Georgia. Light-trap records from Tifton, Georgia, indicate that the borer\u27s seasonal life history is very similar to its life history in South Carolina (31) and in Alabama (32). There are three complete generations each year and a fourth-generation completes development in most years. Although official records do not show the presence of the borer in Florida, records from the southern tier of counties in Alabama (H. F. McQueen, personal communication) and in Georgia (116) indicate that com-growing areas of the Florida panhandle probably are infested. Showers, Reed & Brindley (109) conducted laboratory studies and concluded that the Georgia borer had adapted to the photoperiod-temperature interaction of the region and was capable of producing large numbers of moths for the summer and autumn genera­tions. Chiang (20) studied the dispersion of the borer in Minnesota and in South Dakota from 1945 to 1970 and suggested that after the initial invasion in 1943, two distinctly different populations could have invaded Minnesota, one in 1952 and one in 1966. Chiang & Hodson (21) concluded that populations in the Waseca, Minnesota, area were kept at relatively low levels by environmental factors, but that with favorable temperatures, the borer populations could return to an economically significant level

Differentiation and gene flow among island and mainland populations of the true armyworm, Pseudaletia unipuncta (Haworth) (Lepidoptera: Noctuidae)

Copyright © 2003, NRC Canada. Reproduced by permission.The genetic structure of populations of the true armyworm, Pseudaletia unipuncta (Haworth) (Lepidoptera: Noctuidae), in the Azores archipelago was studied using polyacrylamide-gel electrophoresis. Four enzyme systems (aldehyde oxidase, esterase, phosphoglucomutase, and phosphoglucose isomerase) were examined in six populations from islands in the Azores (Santa Maria, São Miguel, Terceira, Pico, Faial, Flores) and compared with those from populations from mainland Portugal and Canada. The North American and European populations are not clearly separated from the Azorean ones. Similarly, studies of different enzyme systems (aldehyde oxidase, esterase, malic enzyme, sorbitol dehydrogenase, manose-6-phosphate isomerase, and phosphoglucomutase) over 2 years (1997 and 1998) at different times of the year (spring, summer, and autumn) and at three different altitudes (0, 250, and 500 m above sea level) on three different islands (Santa Maria, São Miguel, and Faial) uncovered no distinct differences. These results, obtained from classically used loci, suggest that there is still some gene flow between sites or that island populations have not been isolated for sufficient time to have diverged from founder populations.RÉSUMÉ: La structure génétique des populations açoriennes de la légionnaire uniponctuée Pseudaletia unipuncta (Haworth) (Lepidoptera : Noctuidae), a été étudiée à l'aide d'enzymes séparées par électrophorèse sur gel de polyacrylamide. Quatre systèmes enzymatiques (aldéhyde oxydase, estérase, phosphoglucomutase et phosphoglucose isomerase) ont été analyses chez six populations des Açores (îles de Santa Maria, São Miguel, Terceira, Pico, Faial et Flores) et chez des populations portugaise et canadienne. Les populations européenne et américaine ne sont pas nettement séparées des populations açoriennes. De la même manière, l'étude de six systèmes enzymatiques (aldéhyde oxydases, estérase, enzymes maliques, sorbitol déshydrogénases, manose-6-phosphate isomérases et phosphoglucomutases) durant deux années (1997 et 1998), à différentes périodes de l'année (printemps, été et automne) et à trois altitudes différentes (0, 250 et 500 m) sur trois lies (Santa Maria, São Miguel et Faial) n'a pas dévoilé de divergences évidentes, Ces résultats obtenu à partir de locus classiquement utilisés et en nombre suffisant, suggèrent qu' il subsiste un certain flux génique entre les populations étudiées, et (ou) que les populations insulaires sont isolées depuis trop peu de temps pour avoir pu diverger des populations fondatrices