02120naa a2200289 a 450000100080000000500110000800800410001910000160006024501180007626000090019452013850020365000110158865000100159965000320160965000090164165000120165065300110166265300200167365300100169365300110170365300120171465300090172665300100173570000170174570000180176277300500178010711781992-06-10       1990    bl ---       0--  u    #d1 aFELD, S. J.  aInfluence of Drip and Furrow Irrigation on Phytophthora root rot of citrus under field and greenhouse conditions.  c1990  aThe influence of drip and furrow irrigation on the distribution of populations of Phytophthora parasitica and citrus roots in soil was examined under field conditions and in the greenhouse and lathhouse. Duringa 2-yr field study in a 70-yr citrus orchard, the soil population of P. parasitica was significantly lower under drip irrigation than under furrow irrigation; however, this difference was evident only during the summer months when the fungus was most active. The abundance of citrus roots under furrow irrigation increased with distance from the furrow center. Citrus roots under drip irrigation were uniformly distributed in the area wetted by the emitter. Distribution of P. parasitica propagules correlated directly with the distribution of citrus feeder oot rot of citrus seedings was most severe where seedings were wateredby drip irrigation or kept constantly moist by furrow irrigation. Seedings that received water by furrow irrigation that allowed the soil todry sufficiently between irrigation were able to produce more feeder roots than seedings grown under drip irrigation. Data obtained from greenhouse and lathhouse studies that the commonly recommended method of furrow irrigation that allows the soil dry to -50 to - 70 cb um between irrigation favors the host plant and reduces damage by P.parasitica more than the other irrigation methods investigated.  aCitrus  aCampo  aIrrigação por Gotejamento  aRaiz  aViveiro  aCitros  aDrip irrigation  aField  aFurrow  aNursery  aRoot  aSulco1 aMENGE, J. A.1 aSTOLZY, L. H.  tPlant Diseasegv.74, n.1, p.21-66, jan. 1990.