Vol. 12, Issue 3 (2023)

Author(s):
Asalkar UA, Gorantiwar SD and Bhalekar MN

Abstract:
Within the genus Pseudoperonospora (Peronosporaceae), the most popular and economically important species are Pseudoperonospora cubensis, Rostovzev, which causes downy mildew disease in bitter gourd. Seven types fungicidal treatments were applied during this research trial on bitter gourd such as 1) Absolute control (water spray), 2) Metalaxyl 4% + Mancozeb 64% WP @ 2 g/lit, 3) GI Chitosan @ 1 ml/lit, 4) Potassium salt of active phosphorus @ 4 g/lit, 5) T₂ and T₃ alternatively, 6) T₂ and T₄ alternatively and 7) T_2, T_3, and T₄ alternatively. Spectroradiometer was placed in Hyspec laboratory CAAST-CSAWM MPKV Rahuri. Treatment wise healthy and downy mildew diseased leaf samples were collected and brought into the Hyspec laboratory for further investigation. Spectroradiometer has given the spectral signature of each treatment having wavelength 350nm to 2500nm. The data obtained by this technique was analyzed in the software SVC HR-1024i which indicates the NDVI (normal difference vegetation index) values. Overall present research showed the highest NDVI mean values were obtained in treatment 7) T_2, T_3, and T₄ alternatively i.e (Metalaxyl 4% + Mancozeb 64% WP, GI Chitosan @ 1 ml/lit and Potassium salt of active phosphorus @ 4 g/lit alternatively) followed by T₄ (Potassium salt of active phosphorus @ 4 g/lit), T₆ (T₂ and T₄ alternatively, T₅ (T₂ and T₃ alternatively), T₂ (Metalaxyl 4% + Mancozeb 64% WP @ 2 g/lit), T₃ (GI Chitosan @ 1 ml/lit. The minimum NDVI mean was noticed under treatment T₁ (absolute control: water spray). All attempted disease management treatments (T₂ to T₆) were significantly superior over T₁ (absolute control: water spray).