Locomotion and Resting activities of Water Strider Cylindrostethus costalis costalis Schmidt, 1915 (Gerridae) in relation to surface tension in selected ponds from Sozhampettai, Mayiladuthurai District, Tamilnadu, India

Abstract :

Plant diseases are the most important causes of crop loss world over and thus impose a major threat to global food security. Rice suffers from many diseases caused by fungi. Among the fungal diseases, blast caused by Pyricularia oryzae and sheath blight caused by Rhizoctonia solani are the most prevalent and destructive ones. Most of these diseases are managed by adopting the chemical methods of control, which pose several health and environmental hazards. The harmful chemicals can enter into human body and cause severe diseases. Keeping view of this, plant sources with potential antifungal activities were screened, formulated and used to manage these diseases. The following plants namely Azadirachta indica, Ocimum sanctum, Adhatoda zeylanica, Pongamia pinnata, Ricinus communis, Vitex negundo and Acorus calamus were selected on the basis of their potential antifungal activity and their disease control ability, and they were assessed with cow urine in different concentrations and by using plot trial methods. The infected plant parts of the paddy were collected from the field, and the fungal pathogens namely Pyricularia oryzae and Rhizoctonia solani, which causes the disease of blast and sheath blight respectively, were isolated on selective media, purified, maintained on Potato Dextrose Agar (PDA) medium and their susceptibility with these selected herbal sources were assessed by food poison technique. The results showed that the extent of growth of these fungi were less when compared to the control. Plot trial also revealed the potential influence of these herbal formulations in the ability to control the diseases.