[Laboratory research on the action of Paraquat, Pyrazophos, Seaweeds and Trichlorphon on honeybees]

anglais. Paraquat (1,1'-dimethyl-4,4'-bipyridylium di (methyl sulphate)), which is an herbicide widely used in agriculture and regarded as relatively nontoxic to honeybees, pyrazophos (O-6-ethoxycarbonyl-5-methylpyrazolo [1,5-a] pyrimidin-2-ylO, O-diethyl phosphorothioate), which is described as a systemic fungicide with only a limited insecticidal activity and is sprayed on blossoming cucurbitaceae, seaweeds, which are an organic complex integrating the nutrition used also on blossoming crops, trichlorphon (dimethyl 2,2,2-trichloro-1-hydroxyethylphosphonate), which is an insecticide responsible for honeybee havoc in poplar zones of Piedmont, were tested by ingestion and by indirect contact on foraging honeybees under laboratory conditions. The results of the trials showed: paraquat highly toxic by ingestion and by contact with a slow and progressive action which appears fully by the third day of the tests: pyrazophos highly toxic by ingestion even at doses 64 times lower than those recommended for crop spraying and by contact even 52 hours after spraying; seaweeds nontoxic; trichlorphon highly toxic by ingestion even at doses 256 times lower than those for crop treatments and by contact too at halved doses. The very serious hazard arising to the foraging and pollinating honeybees from using paraquat, pyrazophos and trichlorphon is clearly revealed

italien. Alghe marine, prodotto integratore della nutrizione impiegato in fioritura, paraquat, erbicida ampiamente usato in agricoltura e ritenuto relativamente non tissico per l'ape, pyrazophos, indicato come fungicida sistemico con scarsa attivita insetticida e consigliato su cucurbitacee in fioritura, trichlorphon, insetticida responsabile di stragi di api in zone pioppicole piemontesi, sono stati saggiati in laboratorio per ingestione e per contatto. I risultati delle prove hanno indicato: alghe marine, non tossiche; paraquat, altamente tossico per ingestione e per contatto, con azione lenta e progressiva che si rivela pienamente entro il terzo giorno delle prove; pyrazophos, altamente tossico per ingestione anche a dose 64 volte inferiore a quella suggerita per i trattamenti alle coltivazioni e per contatto anche 52 ore dopo il trattamento; trichlorphon, altamente tossico per ingestione anche a dose 256 volte inferiore a quella suggerita per i trattamenti alle coltivazioni e per contatto anche a dose dimezzata. Il grave pericolo derivante all'ape bottinatrice e impollinatrice dall'uso di paraquat, pyrazophos e trichlorphon e chiaramente denunziato