Practical 1 and 2: Introduction to Phytopathological Techniques

INTRODUCTION TO PHYTOPATHOLOGICAL TECHNIQUES

Phytopathological is the scientific study of diseases in plants caused by pathogens and environmental conditions. Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Not included are ectoparasites like insects, mites, vertebrate, or other pests that affect plant health by eating of plant tissues. Plant pathology also involves the study of pathogen identification, disease etiology, disease cycles, economic impact, plant disease epidemiology, plant disease resistance, how plant diseases affect humans and animals, pathosystem genetics, and management of plant diseases.

OBJECTIVE

·         -To study about techniques of preparation of slide under microscope.

·         -To study the types of culture media that can be used for each diseases.

·         -To know the method of sterilization when preparing slides.

ACTIVITY 1: PREPARING SLIDE FROM FUNGAL CULTURE (ASPERGILLUS SP.)

MATERIALS AND APPARATUS:

                              

               i) Needle 

              ii) Slides

             iii) Spirit

             iv) Spirit lamp

              v) Lactophenol cotton blue (LCB)

             vi) Fungal specimen

            vii) Microscope

METHOD

    

1) The needles are dipped into the spirit and after that it need to heated up with spirit lamp until the needle turns red. This process is to ensure needle are free from other microorganism

      2) A drop of Lactophenol cotton blue (LCB) was prepared on a clean slide as a staining agent

       3) The needle was used to transfer fungal specimen

        4) The fungal specimen that transferred by needle are putted on the LCB and gently put the cover slip on it.

5) After that, slide were slowly placed above lamp. This function is to remove the trapped bubbles also moisture at the slide sample.

RESULT

The slide of Aspergillus sp was observed through the microscope:

ACTIVITY 2 : PREPARING CULTURE MEDIA (POTATO DEXTROSE AGAR, PDA)

MATERIALS AND APPARATUS:

             i)   PDA powder

            ii)   250 Distilled water

           iii)  Conical flask

           iv)  Autoclave

            v)   Petri Dish

METHOD

    1) The 250 ml PDA was prepared by each group.

    2) The ready-to-use PDA powder was weighted accordingly to manufacturer’s instruction and put into a conical flask.

    3) The 250 ml of distilled water was measured, poured into the conical flask with medium and shook well to dilute the PDA powder

    4) The prepared solution was sterilized in an autoclave at 15 p.s.i, 120°C for 20 minutes.

    5) The medium was left to cool down after sterilixation until the flask can be hold comfortably. The medium was poured into petri dishes in the laminar hood

RESULT

After it was cooled down. The culture media are ready to use for inoculation of microorganisms.