plastique de serre

CONT: Plastique de serre : contribution des matériaux plastiques à la maîtrise du microclimat.

CONT: Greenhouse plastics affect tomato pollination by influencing bee activity and bee loss through the ventilation systems. There is a significant difference in bee loss among plastic types ... . CT plastic, one of the less commonly used greenhouse plastics, experienced less bee loss than AT Duratherm, Patilux, and both AT Bee Poly and De Klerk together ... . The likely explanation for these results is that under CT plastic, bees are less able to visually detect the open vents because of the relatively small contrast between the transmitted light and the light through the vents. Our spectrophotometry results ... indicate that of the plastics tested, only CT plastic allows transmission of UV light. Because of this, fewer bees fly out of these greenhouses and die during the winter months.
OBS: Greenhouse tomatoes and pollination by bumblebees. ... Bumble bee keeping in greenhouses has encountered some problems because of the escape of the bees ... through open vents in late winter and early spring. ... New understandings in insect colour vision (Backhaus 1993) have suggested ways by which the visual target of the open vents (daylight with UV) ... versus the greenhouse roof and walls (attenuated UV) can be disguised by coloured transparent flaps or blocked by screening so that the bees are not attracted and can not escape. The former would be easier and cheaper. UV light encourages the germination of spores of grey mould (Botrytis), so UV opaque plastics are favoured.