02565naa a2200205 a 450000100080000000500110000800800410001910000200006024500910008026000090017152019760018065000220215665000140217865000100219265000090220270000230221170000290223470000200226377300760228314641622006-05-22       2004    bl ---       0--  u    #d1 aYORINORI, M. A.  aEffect of time of spraying of fungicide and foliar nutrient on soybean powdery mildew.  c2004  aWith the objective of determining the effects of initial infection level (% leaf area infected, % l.a.i.) at the time of fungicide and foliar nutrient application for the control of powdery mildew, a study was carried out under greenhouse conditions at Embrapa Soja, Londrina, P.R. The fungicide tebuconazole (100 g a.i./ha/application) and sulphur fungicide (2.0 kg a.i./ha/application), sprayed at 20, 30, 40 and 50% l.a.i. (growth stages V3 and V5, between R5.1 and R5.3), and three applications (at V3, V4 and R5.1, beginning at 20% l.a.i.) of tebuconazole were compared with sulphur foliar nutrient (sulphur at the dose of 125 g a.i./ha/application). The highly susceptible BR-16 cultivar was used in a completely randomized design with 11 treatments, five replications (pots) and five plants per pot. The parameters evaluated were: % l.a.i., % yellowing leaf when the control reached growth stage R7.2 (between 50 and 75% yellow/mature leaves), % defoliation (% defol.) when the control plants reached R8.2 (pre-harvest maturity), number of pods and seeds and seed weight (s.w.) per plant. The area under the disease progress curve (AUDPC) was determined based on disease progress. The % l.a.i. and AUDPC of the control (98% and 65.41) differed from other treatments (3.564.2% l.a.i. and 13.5740.59 AUDPC). The % l.a.i. for the sulphur fungicide treatment (41.964.2%) and sulphur foliar nutrient (49.8%) were greater than for tebuconazole (3.528%). The % defol. of the control (90%) differed from tebuconazole applied at 30% initial infection (48%), with three applications (45%), and from sulphur foliar nutrient (47%). The s.w./plant of the control (2.23 g) was lower than that of tebuconazole treated at 40% IL (3.03 g) and at 20% IL (3.35 g) and for sulphur foliar nutrient (3.7 g). The initial disease severity (2050% l.a.i.) did not affect the level of powdery mildew control and the sulphur foliar fertilizer resulted in greater number and higher s.w./plant.  aDoença de Planta  aFungicida  aFungo  aSoja1 aKLINGELFUSS, L. H.1 aPACCOLA-MEIRELLES, L. D.1 aYORINORI, J. T.  tJournal of Phytopathology, Berlingv. 152, n. 3, p. 129-132, Mar. 2004.