Kora Cezarina, McDonald Mary Ruth, Boland Greg J
Department of Plant Agriculture.
Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
Plant Dis. 2005 Jun;89(6):549-557. doi: 10.1094/PD-89-0549.
Four canopy management treatments were evaluated in carrot (Daucus carota) production in Bradford Marsh, Ontario, in 2001 and 2002: (i) unclipped control; (ii) unclipped canopy with manual removal of collapsed senescing leaves at 2-week intervals following the first appearance on the soil; (iii) lateral clipping of the canopy at the initial emergence of apothecia, leaving the debris in the furrow, and (iv) lateral clipping of the canopy with manual removal of the debris from the furrow. Clipping reduced the canopy width by ca. 20% on both sides of the carrot bed by cutting off overlapping leaves above the furrow and senescing foliage on the soil surface. Maximum air and soil temperatures were up to 9.2 and 3.1°C lower, respectively, and relative humidity was up to 30% higher in unclipped canopies than in clipped canopies. The total number of apothecia in clipped plots was reduced by 74 and 76% compared with unclipped plots in 2001 and 2002, respectively. Canopy clipping reduced the quantity of apothecia in the crop by creating an unfavorable microclimate for the development of S. sclerotiorum without affecting the fresh foliar and root weights of carrot at harvest. The presence of clipped foliar debris in the furrow affected the number of apothecia in 2001; however, apothecia under the debris are unlikely to contribute to the overall inoculum in the crop. Lateral clipping also appeared to control Sclerotinia rot of carrot where it occurred (in 2001). This is the first report that documents and quantifies the effects of canopy architecture on the microclimate, development of apothecia of S. sclerotiorum, and Sclerotinia rot in carrot crops.
2001年和2002年，在安大略省布拉德福德沼泽地的胡萝卜（胡萝卜属）生产中，对四种冠层管理处理方法进行了评估：（i）未修剪对照；（ii）未修剪冠层，在叶片首次出现在土壤上后，每隔2周人工去除枯萎衰老的叶片；（iii）在子囊盘最初出现时对冠层进行侧向修剪，将残枝留在沟中，以及（iv）对冠层进行侧向修剪并人工清除沟中的残枝。通过剪掉沟上方重叠的叶片和土壤表面衰老的枝叶，修剪使胡萝卜床两侧的冠层宽度减少了约20%。未修剪冠层中的最高气温和土壤温度分别比修剪冠层高9.2℃和3.1℃，相对湿度比修剪冠层高30%。与未修剪地块相比，2001年和2002年修剪地块中的子囊盘总数分别减少了74%和76%。冠层修剪通过为核盘菌的生长创造不利的小气候，减少了作物中的子囊盘数量，而不影响收获时胡萝卜的新鲜叶重和根重。2001年，沟中修剪后的叶残体的存在影响了子囊盘的数量；然而，残体下的子囊盘不太可能对作物中的总接种量有贡献。侧向修剪在胡萝卜核盘菌病发生的地方（2001年）似乎也能控制该病。这是第一份记录并量化冠层结构对小气候、核盘菌子囊盘发育以及胡萝卜作物核盘菌病影响的报告。
