01761naa a2200193 a 450000100080000000500110000800800410001910000220006024501310008226000090021352011930022265000120141565000210142765000140144865000150146265300170147770000170149477300560151110510832015-01-07       1994    bl ---       0--  u    #d1 aEL-HAMALAWI, Z.A.  aEffect of wound age and fungicide treatment of wounds on susceptibility of avocado stems to infection by phytophora citricola.  c1994  aBark wounds of avocado (Persea americana) stems of the cultivar Topa Topa became resistant to infection by Phytophthora citricola within 12-14 days after injury. The size of cankers declined significantly  as the time interval betwen woundig and inoculation  increasead. Wounds that were reinjurede after 2 mo of aging became susceptible to infections similar to those of wounds made on previously unwounded stems. Theseresults suggest that chemical treatment applied to fresh bark wounds must protect against P. citricola for at least 14 days to be effective.Fungicide treatments for curing as well as protecting avocado stems against trunk canker disease caused by P. citicola were investigated. Wounds on intact and excised avocado stems were treated whith fosetyl Al, fosetyl Al+Tree Seal, metalaxyl, Bordeaux mixture, Tree Paint, or Tree Seal after infection with P. citricola. The development of cankers was suppressed only  by treatments including fosetyl Al. Wounds wereprotected by fosetyl Al trought the period required for the wound to become resistant to infection. Brief washing of wounds treated with fosetyl Al 24 hr after treatment did not reduce protection of wound site.  aAbacate  aDoença Fúngica  aFungicida  aTratamento  aPhitophthora1 aMENGE, J. A.  tPlant Diseasegv. 78, n. 7, p. 700-704, jul., 1994.