00461nam a2200145 a 450000100080000000500110000800800410001910000160006024501320007626000400020830000100024865300210025865300200027970000160029910905721996-09-03       1939    bl uuuu      00u1 u    #d1 aRIKER, A.J.  aIntroduction to research on plant diseasesba guide to the principles and practice for studying various plant-disease problems.  as.l.: University of Wisconsinc1939  a117p.  aDOENCA DE PLANTA  aPRAGA DE PLANTA1 aRIKER, R.S.