10.22376/ijpbs.2019.10.1.p1-12 Volume 6 Issue 1 2015 (January - March)  3 Descriptor quantitative structure and activity relationship (3d-QSAR) studies for a series of pyrazolone compounds using their semi-empirical quantum chemically derived descriptors and their laboratory reported activities against pathogen viz. lessThan i greaterThan Colletotrichum falcatum lessThan /i greaterThan (ITCC 6656) have been carried out and reported in this present paper. Graphs between observed and predicted activities, both in the terms of p(MIC) lessThan i greaterThan cal lessThan /i greaterThan and p(MIC) lessThan i greaterThan obs. lessThan /i greaterThan viz.-log (MIC) are reported. This is concluded on the basis of these graphs that some of the descriptors computed and taken into account in the present paper have positive contribution towards the activities. The method has been proved to be useful tool for such type of studies. KISHOR ARORA Semi-empirical/3D-qsar/fungal pathogen/pyrazolones 188-203