**2.1 Plant materials**

Fifty medicinal plants (Table-1) were selected in this study based on the information collected from literature (Warrier *et al.,* 1994-1996 and Pullaiah, 2002). All the plant materials were collected in and around Visakhapatnam over the course of the respective growth season during February to April in the year 2005 because of the extracts were generally rich in antibacterial agents after the flowering (sexual) stage and plants from stressful environments (Mitscher *et al.,* 1972). Plant materials were identified with the help of Gamble, "Flora of the Presidency of Madras" and later verified by comparison with the authentic specimens available in the herbariums of NBRI, Lucknow and the Department of Botany, Andhra University, Visakhapatnam. Voucher specimens were deposited in the herbarium of the Botany Department, Andhra University, Visakhapatnam.

#### **2.2 Solvents and chemicals used**

All chemicals were purchased from Qualigens fine Chemicals, Mumbai and SD fine chemicals, Mumbai. All culture media components and antibiotics used in this study were procured from Hi Media, Mumbai, India.

#### **2.3 Tested organisms**

Based on the disease index of Sorghum (Horne and Frederiksen., 1993) crops in which five phytopathogenic microorganisms were selected to screen the antimicrobial inhibition of the selected plant extracts listed in Table-2. The organisms used were procured from Microbial Type Culture Collection & Gene Bank (MTCC), Chandigarh. The lyophilized form of pure strain is reconstituted in sterile water and produced a suspension of the microbial cells. Inoculation was done with sterile inoculating loop to liquid broth medium. Liquid cultures are then incubated to allow cell replication and adequate growth of the culture, for use in bioassays. Following incubation, liquid cultures are refrigerated to store for further use. Typically, 24 hours will provide sufficient growth to allow visibly thick spread of the microbes as required for bioassay. The bacterial strains are maintained and tested on Nutrient Agar (NA) and Potato Dextrose Agar (PDA) for fungi.
