Toxicity and larval growth inhibition of eleven insecticidal proteins of Bacillus thuringiensis were evaluated against neonate larvae of Helicoverpa armigera, a major pest of important crops in Spain and other countries, by a whole-diet contamination method. The most active toxins were Cry1Ac4 and Cry2Aa1, with LC 50 values of 3.5 and 6.3 µg/ml, respectively. At the concentrations tested, Cry1Ac4, Cry2Aa1, Cry9Ca, Cry1Fa1, Cry1Ab3, Cry2Ab2, Cry1Da, and Cry1Ja1, produced a significant growth inhibition, whereas Cry1Aa3, Cry1Ca2, and Cry1Ea had no effect.

The efficacy of a granulosis virus isolated in Spain from Agrotis segetum larvae (AsGV) was field tested and compared with chlorpyrifos and flucythrinate as control agents against A. segetum larvae on corn seedlings. The application of the AsGV through bran wheat bait provided a crop protection similar to that produced by chlorpyrifos and flucythrinate. Significant differences were not found between the levels of protection provided by AsGV when it was applied at a rate of 4.1 × 1012 IB/ha or 4.1 × 1013 IB/ha. Zusammenfassung Wirkung eines spanischen Stammes des Agrotis segetum‐Granulosevirus (Baculoviridae) auf Raupen von Agrotis segetum Schiff. (Lep., Noctuidae) an Mais Es wurde die Wirkung eines in Spanien aus Agrotis segetum‐Raupen isolierten Stammes eines Granulosevirus (AsGV) gegen A. segetum‐Rzupen — im Vergleich zu Chlorpyrifos und Flucythrinat — an jungen Maispflanzen im Freiland getestet. Die Ausbringung des AsGV mittels Weizenkleie‐Ködern führte zu einem Ertragschutz‐Effekt, der in seiner Höhe vergleichbar mit jenem bei Anwendung von Chlorpyrifos und Flucythrinat war. Signifikante Unterschiede bezüglich der Höhe des Schutzeffekts zwischen AsGV‐Raten von 4,1 × 1012 IB/ha und 4,1 × 1013 IB/ha wurden nicht festgestellt.

Apanteles telengai Tobias, Aleiodes gasteratus (Jurine) and Campoletis annulata Tschek parasitized significantly more healthy than granulosis virus (GV)‐infected Agrotis segetum D. & Schiff. larvae. Females of the three parasitoid species that had oviposited previously in GV‐infected A. segetum larvae transmitted the virus to healthy A. segetum larvae in subsequent oviposition. A. telengai and A. gasteratus females also transmitted the GV on unsuccessful oviposition attempts. Male parasites did not transmit the GV. Résumé Taux de parasitisme des chenilles d'Agrotis segetum saines et infectées par le virus de la granulose et possibilités de transmission du virus par 3 parasitoïdes hyménoptères Apanteles telengai, Aleiodes gasteratus et Campoletis annulata parasitent significativement plus les chenilles saines d'A. segetum que les chenilles infectées par le virus de la granulose. Les femelles des 3 espèces ayant pondu préalablement dans des chenilles contaminées par le virus ont transmis le virus à des chenilles saines lors de pontes ultérieures. Les femelles de A. telengai et A. gasteratus transmettent le virus lors de perforations d'hôtes non suivies de pontes. Les mâles ne transmettent pas le virus.

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This study was carried out to improve the rearing methods of endoparasiteHyposoter didymator(Thunberg) for biological control release. The growth and the development ofH. didymatoron the first, second, and third instars ofSpodoptera littoralis(Boisduval) andHelicoverpa armigera(Hübner) under laboratory conditions were investigated. Results indicated thatS. littoraliswas a suitable host for the rearing of H. didymator The development time of the parasite on the second instar of both hosts was almost the same (∼17 d). The age of the female parasite affected the percentage of adult emergence, pupal mortality, and females in the offspring reared onS. littoralishost. The best copulation period ofH. didymatorfemales and males was 36 h that resulted in 51.8% of females in the offspring. The male to female ratio during copulation period, as well as the presence of males after copulation, and the number of host larvae for each parasite female had no effect on parasitism. Results suggested thatS. littoralissecond instar is a suitable host for mass rearing ofH. didymatorparasite, which may improve the use ofH. didymatoras a biocontrol agent.

A nuclear polyhedrosis virus (NPV) has been identified as the etiological agent causing epizootics in natural populations of Spodoptera exigua in the south of Spain. The incidence of this NPV has been determined from samples of larvae collected from sunflower fields and vegetable greenhouses at two sites located 500 km apart. The NPV was the only disease agent identified at both sites. Through the period surveyed the percentage of NPV-infected larvae increased from 4.3% to 23% and from 22.5% to 100% in S. exigua larvae collected from sunflower fields and vegetable greenhouses respectively. No mortality attributed to the NPV was found in Spodoptera littoralis, Heliothis armigera, Peridroma saucia and Plusia gamma larvae collected in the same survey from the same sites. This is the first report of epizootics caused by NPV in S. exigua populations in field and greenhouse crops in Europe.

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