The Palearctic sevenspotted ladybeetle, Coccinella septempunctata L., well established in North America, has now spread through parts of five Canadian provinces and 34 contiguous eastern states of the United States. In southern coastal Delaware in June 1984, a mass appearance of C. septempunctata occurred where wind systems brought masses of these beetles into the area from unknown sources and dropped them into the seawater. Large numbers then washed up on beaches, and some surviving beetles annoyed vacationers and even bit some people. We speculate on the original establishment of this insect in North America. Presenting evidence previously overlooked, we add to speculation that early intentional releases led to establishment of this predator in North America. However, accidental importation on transoceanic ships cannot be ruled out.

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In New Jersey, Typhlodromus pomi (Parrott) was the only predacious phytoseiid mite on most non-sprayed apple and deciduous trees. It also became the most numerous phytoseiid mite recolonizing apple trees a year after toxic spray residues had dissipated. Amblyseius fallacis (Garman) was the first phytoseiid mite collected from apple trees following cessation of toxic sprays and was usually abundant at the time of large red mite populations; later, an influx of several different species occurred. A. fallacis was the most common phytoseiid mite on low growing plants and was able to tolerate higher residues of toxic materials than other species. Other phytoseiids taken from sprayed apple trees in order of abundance included A. driggeri n. sp., A. amicus (Chant), T. longipilus Nesbitt, T. conspicuus (Garman), T. mexicanus (Garman), T. caudiglans Schuster, and A. pepperi sp. n. Species other than T. pomi found on non-sprayed apple trees were A. finlandicus (Oudemans), T. longipilus, T. caudiglans, and T. conspicuus. None of these species was entirely confined to apple. Five other species were collected that were not found on apple: T. flumenis Chant, T. pyri Scheuten, A. elongatus (Garman), A. okanagensis (Chant), and A. picketti sp. n. Three species collected from greenhouse plants in association with tetranychid mites were: A. fallacis, T. longipilus, and A. picketti.Three new species of Amblyseius are described. Two undescribed males and the spermathecae of the females are illustrated.

A degree-day model was developed for Alberta populations of Ostrinia nubilalis Hubner. Starting with overwintered fifth-instar larvae, the model calculates the temporal distribution of first-and second-instar larvae which are the stages most vulnerable to chemical suppression. Predictions from three alternative models were compared against field data from southern Alberta. Use of a standard 10°C growth threshold to calculate physiological time scales allowed predictions as accurate as those obtained using either a pooled threshold (1 1.4"C) calculated specifically from Alberta populations, or a model using two thresholds (12.3"C for fifth-instar larvae to adult and 10.2"C for eggs to second-instar larvae) that incorporated significant differences in growth characteristics observed among life stages. We conclude that standard thresholds are sufficient for degree-day models for northern populations of 0 . nubilalis. The standard model (to = 10°C) predicts that moth emergence will peak at ca. 145 degree-days after median pupation, and that numbers of eggs, and first-and second-instar larvae should peak at 200, 310, and 450 degree-days, respectively. Model predictions can be used to time sampling effort in support of management decisions. Keker, D.H., D. A. Lee et J.R. Spence. 1990. Utilisation des seuils normaux de tempkrature pour faire la pkdiction phCnologique de la pyrale de mais (Ostrinia nubilalis Hiibner) en Alberta. Can. Ent. 122: 1247-1258. RCsumCUn modble de degrks-jours a ttk dkveloppk concernant les populations d'ostrinia nubilalis Hubner en Alberta. Dkbutant avec les larves hivernees du cinquibme stade, le modble estime la distribution temporelle des larves du premier et du deuxibme stade, qui sont les plus vulnkrables a la suppression chimique. Les predictions issues de trois modkles differents ont kt15 comparkes avec les donnkes obtenues dans le champ au sud de 1'Alberta. L'utilisation d'un seuil de croissance normal de 10°C pour estimer les Cchelles physiologiques temporelles a permis des predictions aussi valables que celles obtenues par l'utilisation soit d'un seuil accru (1 1,4"C) calculC spkcifiquement a partir des populations de l'Alberta, soit d'un modble qui utilise deux seuils (12,3"C en ce qui concerne le developpement du cinquibme stade larvaire 2 l'adulte et 10,2"C en ce qui concerne le developpement de l'oeuf aux larves du deuxikme stade), qui ont incorpores des diffkrences significatives des caractbres de croissance constatees parmi les stades vitaux. Nous avons conclu que les seuils normaux sont suffisants pour les modkles degrks-jours pertinents aux populations septentrionales d'O. nubilalis. Le modble normal (to = 10°C) prkdit que 1'Cclosion des adultes atteindra son apogke a ca. 145 degresjours suivant la date de nymphose moyenne et que les nombres d'oeufs et de larves du premier et du deuxikme stade devraient atteindre leurs apogees a 200,3 10 et 450 degrksjours, respectivement. Les predictions obtenues en utilisant les modbles peuvent ttre employees pour appuyer les decisions de ge...