Mycology

• Scale Insects (Coccidae) Characteristics:
• Pair-by-Pair Matching:
• Brown soft scale $\rightarrow$ (IV) Coccus: Coccus hesperidum is the cosmopolitan brown soft scale attacking citrus and greenhouse ornamentals.
• Black scale $\rightarrow$ (III) Saissetia: Saissetia oleae is known worldwide as the black scale of olive, citrus, and deciduous fruit crops.
• Yellowish white soft scale $\rightarrow$ (II) Ceroplastes: Ceroplastes floridensis / C. rubens secrete thick yellowish-white or pinkish wax coatings.
• Chocolaty nymphs, females with white mealy substance $\rightarrow$ (I) Parasaissetia: Parasaissetia nigra (nigra scale) exhibits shiny dark brown-black chocolaty adult scales.
• Correct Choice: Option 4 maps (A)-(IV), (B)-(III), (C)-(II), (D)-(I).

Correct option: (4) (A) - (IV), (B) - (ND, (€) - (), (B) - (0)

• Membrane Filter Sterilization (Cold Sterilization): In microbiological and phytopathological laboratory protocols, heat-labile liquids (such as antibiotic solutions, vitamins, growth regulators, and viral inocula) cannot be autoclaved.
• Standard Pore Size: They are sterilized by membrane filtration using cellulose acetate, nylon, or PES membrane filters with a standard nominal pore diameter of $0.22\,\mu\text{m}$ (commonly specified as $0.2\,\mu\text{m}$).
• Sterility Mechanism: A $0.2\,\mu\text{m}$ pore size physically excludes all vegetative bacterial cells (Brevundimonas diminuta is used as the standard validation challenge), fungi, and mycoplasmas while permitting aqueous solutions to pass through.
• Conclusion: Filters of $0.2\,\mu\text{m}$ pore size are normally used (Option 3).

Correct option: (3) 0.2 um

• Mounting Media in Diagnostic Mycology: The most widely utilized universal mounting and staining reagent for temporary microscopic mounts of fungal mycelia, conidiophores, and spores is Cotton blue in lactophenol (LPCB).
• Chemical Constituents and Functions:
• Phenol: Rapidly kills fungal hyphae and inactivates autolytic enzymes.
• Lactic acid: Preserves fungal cellular morphology and structures.
• Glycerol: Maintains an osmotic balance and prevents the mount from drying out.
• Cotton blue (Aniline blue): Acidic stain that binds intensely to fungal cell-wall chitin, staining hyphae and reproductive spores bright blue.
• Conclusion: Cotton blue in lactophenol is the standard mounting medium (Option 2).

Correct option: (2) Cotton blue in lacto-phenol