Uniformly UC ring-labeled atrazine was applied to a mineral soil under field conditions. Nine years after application of the herbicide soil samples were collected for analysis. The soil contained about 50% UC residues in the bound (nonextractable) form. The bound 14C residues were distributed among the various soil humic fractions. In addition to the parent herbicide a considerable proportion of these residues was comprised of the hydroxy analogues of atrazine and their dealkylated products.

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The authors --members of the OILB working group on genetic control of the Europan cherry fruit fly, Rhagoletis cerasi L. --describe in this second report the development of a standard trap for the target species and its applications in the framework of the genetic control procedures in progress. The trap has increased the attractiveness for the flies about t00 times compared with the traditional bait traps and has proven its effectiveness in recent suppression programs in the field.(*) Second report of the OILB working group on genetic control of R. cerasi.

The aim of this study was to find out to which extent the narrow host spectrum of Rhagoletis cerasi Linné (Trypetidae, Diptera) is due to sensory barriéres or unsuitable texture and composition of nonhost fruits. Preference or partial avoidance of fruit dummies made of thin‐walled wax hemispheres (fig. 6) and impregnated with either host‐ or nonhost‐volatiles by gravid R. cerasi was demonstrated. The volatiles of a fruit species were obtained by passing purified air (3 1/min) for 48 hours over ˜ 1 kg of unripe berries (table) to an adsorbent (fig. 8), from which the odour was recovered by solvent extraction. The host fruit odours derived from the fly honeysuckle (Lonicera xylosteum, Caprifoliaceae) or the sweet cherry (Prunus avium, Rosaceae) increased the rate of oviposition by 27 or 36%, whilst the nonhost odours obtained from fruits of the mealy tree (Viburnum lantana, Caprifoliaceae), the cornel tree (Cornus mas, Cornaceae) or the common dogwood (Cornus sanguinea, Cornaceae) subdued it by 37, 33 or 52%, respectively. The oviposition rate of R. cerasi can thus be enhanced by host fruit odours or suppressed by odours of nonhost fruits. Female cherry fruit flies were found to lay 1.7‐2.2 times more eggs in fruit dummies displaying a luminosity contrast with the background (black dummies on white surface) than in dummies which had the same coloration as the background (either black or white). Thus, the luminosity contrast encouraged oviposition more than the odour of host fruits (fig. 7). Host finding of R. cerasi seems to depend on phototelotactic orientation and host recognition on kinaesthetic as well as tactile behaviour responses, while the extent of egg laying appears to be regulated by host and nonhost odours. Zusammenfassung Optische und chemosensorische Reize zur Wirtserkennung und Eiablage der Kirschfruchtfliege Rhagoletis cerasi L. Es sollte geklärt werden, ob das beschränkte Wirtsspektrum der Kirschfruchtfliege Rhagoletis cerasi Linné (Trypetidae, Diptera) auf sensorischen Barrieren oder auf ernährungsphysiologisch ungeeigneter Zusammensetzung bzw. Beschaffenheit der Früchte von Nichtwinen beruht. Die Bevorzugung bzw. partielle Vermeidung dünnwandiger Wachshalbkugeln (als Fruchtattrappen, Abb. 6), imprägniert mit den Düften der Wirts‐ bzw. Nichtwirts‐Früchte, von trächtigen Weibchen der Kirschfruchtfliege wurde gezeigt. Die zu untersuchenden Fruchtdüfte wurden gewonnen, indem jeweils ˜ 1 kg der noch unreifen Beeren (Tab.) während 48 Stunden mit Luft überströmt (3 1/min) und die flüchtigen Stoffe in einem Adsorptionsmittel (Abb. 8) aufgefangen und später daraus extrahiert wurden. Die Fruchtdüfte der Roten Heckenkirsche (Lonicera xylosteum, Caprifoliaceae) oder der Vogelkirsche (Prunus avium, Rosaceae) erhöhten die Eiablage an Fruchtattrappen um 27 bzw. 36%, wogegen sie von den Fruchtdüften des Wolligen Schneeballs (Viburnum lantana, Caprifoliaceae), der Kornelkirsche (Cornus mas, Cornaceae) oder des Roten Hartriegels (Cornus sanguinea, Cornaceae) um 37, 33 bzw. 52% herabgesetzt wurde. Es wurde...

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