Morphological Character Variations in Lasiodiplodia Species: Pathogen of Inflorescence Dieback in Cashew Growing Ecologies of Nigeria

Nine isolates of Lasiodiplodia theobromae were collected from cashew inflorescences showing typical
symptoms of dieback disease in nine different farms belonging to various cashew growing ecologies
of Nigeria. The result revealed that most of the Lasiodiplodia species isolates exhibited significant
differences in morphology, colour and spore dimensions. The colony growth rate of Lasiodiplodia
species range from 11.95 mm to 14.17 mm, colony texture and colour of the isolates in the obverse
were fluffy dark mouse grey, fluffy mouse grey, fluffy olivaceous grey or fluffy groh grey while the
reverse colour of the isolates was either greyish blue or sky grey. Sporulation was observed at varied
degrees in all the Lasiodiplodia species isolates except in isolates from Oro and Ejule and likewise is
the numbers of pycnidia produced varied in all the isolates across growing ecologies. Significant
variations were observed in the characters and morphology of the Lasiodiplodia species isolates
causing inflorescence dieback of cashew in Nigeria. Conidia of all isolates are septated with single
septa but the septa sizes varies and conidia sizes also differ. Eigenvalues and variance proportion
consistently decreased among selected characters and the proportional contribution of each character
to the total variance also varied in dimension and quantity. Four clusters significantly evolved in the
dendogram with 2, 2, 4 and 1 isolates within each cluster.