CONTROL OF PEAR SCAB WITH HYDRATED LIME ALONE OR IN SCHEDULES WITH OTHER FUNGICIDE SPRAYS

Hydrated lime, thiram, flusilazole and various alternating combination s of the three materials were compared in spray schedules from green t ip until summer at two sites over 3 years to control pear scab caused by Venturia pirina. Six to ten sprays of 2% hydrated lime significantl y (P = 0.05) reduced the incidence of fruit scab (by up to 41%) or lea f scab (by up to 83%) when applied to trees in four trials. Hydrated l ime sprays were less effective than a similar number of thiram or flus ilazole sprays. In two trials, schedules of hydrated lime or flusilazo le sprays were associated with increased fruit yield (up to 89%) as me asured by crop weight. Some hydrated lime schedules were associated wi th slight phytotoxicity in the form of enlarged lenticels on fruit at harvest. No problems resulted from multiple applications of hydrated l ime in commercial airblast sprayers equipped with diaphragm pumps. (C) 1998 Elsevier Science Ltd. All rights reserved