Evaluation of the efficiency of the polystyrene cone and geotextile fabric for the protection of the vine against late spring frosts in Québec for small exploitations and tree plantations

<p style="text-align: justify;">Based on temperature measurements recorded within the aerial portions of the <em>Vitis vinifera</em> L. var. Melon vine variety during spring frosts, it was possible to evaluate the efficiency of two methods of phytoprotection : the polystyrene cone and geotextil~ fabric. Experimentation was carried out in a vineyard located near the City of Sherbrooke in Québec during the critical hours (3 h 00 and 6 hOO, local lime), on may 14, 1994. Measurements of interstitial temperatures were acquired using electronic thennometers inserted into the vine shoots and trunks and relayed to a data acquisition system. Result show that: 1) the lowest temperatures are recorded in shoots and trunks located close the ground in the case of vine stocks without protection; 2) of the two methods of protection, the polystyrene cone is the most efficient since it maintains the mean temperature of the shoots and trunks 1,7 oC above those protected by geotextile fabric ; 3) under both types of protection, the coldest temperature are recorded in the highest shoots; 4) since fruit buds are more numerous towards the summit of the stock, it becomes clearly disadvantageous to use geotextile fabric in case of radiative frost because temperatures are col der by 1,5 oC than in the case of shoots \\-ithout protection.</p>