Steven C. Krause

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In three experiments, red pine (Pinus resinosa Ait.) seedlings and trees were subjected to artificial defoliations of varying intensities and subsequent growth, gas exchange and nutritional responses were monitored. In Experiment 1, 2-year-old seedlings received 0, 1 or 2 50% defoliations during a single growing season and were maintained in 1 of 3 low(More)
Laboratory and field experiments were conducted to determine the efficacy of two Bacillus thuringiensis Berliner formulations, Novodor and Raven, for controlling cottonwood leaf beetle, Chrysomela scripta F. (Coleoptera: Chrysomelidae). In laboratory bioassays, larvae or adults were added to petri dishes containing Populus x euramericana Guinier 'Eugenei'(More)
Larch sawfly, Pristiphora erichsonii Hartig, and larch needlecast fungus, Mycosphaerella laricinia (R. Hartig) Neg., are early season defoliators restricted only to Larix host trees. Larch defoliation (100%) by either the fungus or insect, but not mechanical removal, induced systemic responses that reduced sawfly consumption and digestion rates one year(More)
Deciduous larches,Larix spp., and evergreen pines,Pinus spp., are sympatric Pinaceae conifers. Adjacent monocultures of 10-year-oldLarix decidua Mill, andPinus resinosa Ait. were subjected to single-season artificial defoliation by clipping from 0% to 99% of each needle. Survival, above-ground productivity, and architecture were measured for 36 months.P.(More)
Two evaluations of microbial mosquito larvicides were conducted in irrigation fields located along the Odra River near the city of Wroclaw, Poland. In the first evaluation, 3 dosages each of Bacillus thuringiensis israelensis (Bti)--VectoBac water dispersible granule (WDG) and VectoBac aqueous suspension formulation (12AS)--and Bacillus sphaericus(More)
Rapidly induced responses can alter host plant suitability for insect growth and survival. The effects of defoliation on the suitability of potted 5-year-old red pine, Pinus resinosa Ait., for the sawfly Neodiprion sertifer (Hymenoptera: Diprionidae), were measured in two experiments. In the first, overall larval growth rate increased on seedlings within 8(More)
River samples (e.g. river Rhine, river Neckar, Germany) and samples from five communal sewage treatment plants were investigated for N-(phenylsulfonyl)-glycine, -alanine and -sarcosine, as well as for the corresponding p-toluene analogues. As result of this screening we identified N-(phenylsulfonyl)-glycine as a hitherto unknown polar contaminant. In(More)
The behaviour of N-(phenylsulfonyl)-glycine (PSG) and phenacetin (PHE) in a municipal sewage treatment plant near Heidelberg, Germany, was investigated in the summer of 1997. For that purpose, 10 g of each substance was dissolved and poured simultaneously into the influent. In addition to the spiked compounds, the samples of the influent, the biological(More)
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