BP Singh

-Detection Procedures for Fungal Plant Patl10gens and Salvaging 143examined visually and under low power of stereobinocularmicroscope before subjecting to incubation or any other specializedtests. By this method it is possible to detect sclerotia, smut balls,discolouration, malformations, hypertrophies, fungal spores andother fructifications such as pycnidia, perithecia etc. Also we candetect inert matter which includes broken pieces of plant parts,sand or soil particles, stones and seeds of other crops includingweed seeds.During quarantine processing of germplasm samples ofvarious agri-horticultural crops with this method we couldintercept spore crusts of Peronospora manshurica (downy mildewof soybean); uredio and teleutospores of Puccinia carthamii (rust ofsafflower); bunted grains due to Neovossia indica (Kamal bunt);Tilletia caries and T. foetida (wheat bunts); ergot sclerotia (Clavicepspurpurea) in wheat, rye, barley, oats and a number of grasses etc.2. Microscopic examination of suspensions obtained by seedwashing: The method is used only for surface-borne, contaminatingfungi. The seed is shaken along with water (having a few dropsof detergent) for a fixed period with the help of a shaker ormanually. The resultant suspension may be examined directlyunder a stereobinocular microscope or the suspension may beconcentrated by centrifugation. The concentrate (sediment) can bediluted in small quantities of water and observed under thecompound microscope. The method has been used for detectionof smuts, bunts, downy mildews, powdery mildews, rusts andalso spores of Alternaria, Cercospora, Drechslera, Fusarium,Pyricularia etc.3. . Incubation method: Incubation tests can be used successfullyagainst surface borne as well as internal infections. After plantingof seed, the incubation period gives an opportunity to the dormantmycelium of fungal spores to grow alongwith the host. Mostcommonly used incubation tests are dealt below:(a) The blotter method: Usually 400 seeds of each sample tobe tested are placed on 3 layers of moist blotters in plasticpetritplates (10 to 25 seeds per plate, depending upon the size ofthe seed) and incubated under near ultraviolet light/whitefluorescent tubes in alternating cycles of 12 hours light/ darknessfor 7 days at 20°C±2°C. Identification is mainly based upon thestereobinocular observation. However, slides are made and