IMPORTANT TERMS IN PLANT PATHOLOGY

IMPORTANT TERMS IN PLANT PATHOLOGY

    1. Antibody – a protein produced by specific stimulation when a foreign antigen enters into the blood of an organism. Antibodies get attached with the antigens and make them ineffective .

    2. Antigen – a substance which after entering into a body activates the production of antibody.

    3. Antibiosis – the phenomenon in which a substance produced by one microorganism is harmful to another organism.

    4. Alternate host – one of the two kinds of plants on which a parasitic fungus must develop to complete life-cycle.

    5. Anthracnose – A leaf or fruit spot type of disease caused by fungi that produce their sexual spores in as acervulus.

    6. Blight – a non-restricted tissue disintegrating symptom characterized by general and rapid killing of leaves, flower and stem.

    7. Bacteriostatic – A chemical or physical agent that prevent’ ,multiplication of bacteria without killing them.

     8. Bacteriophage – A virus which infects specific bacteria and kill them.

     9. Blotch –A disease characterized by large and irregular spot or lesions on leaves , shoots and stem.   10.Canker – A necrotic or sunken lesion oil a stem, branch or fruit of a plant.                    11.Carrier – A plant or an organism which carries an infections agent but does not show symptoms of disease produced by the agent.

12. chlorosis – yellowing of green tissue due to chlorophyll destruction.

13. damping off -  Destruction of seedling near the soil surface, resulting in the falling of seedling on the ground.

14.  die back-  Progressive death of shoots and root generally starting at the tip.

15.disinfestant-  An agent that kill pathogens in the environment or on the surface or on the surface of the plant, prior to infection.

16. downey mildew – A plant disease in which the mycelium & spores of the fungus appear as a downey growth on the host surface.

17.epidemic disease- A wide spread and severe outbreak of a disease.

18. endemic disease- A disease which regularly occurs on a particular area of earth or country.

19.etiolation- Yellowing of the plant due to deficiency of the light.

20.exclusion- Control of plant disease by excluding the pathogen or infected plant material from disease free area.

21.exudate- Liquid discharge from plant tissue.

22. facultative parasite- An organism that is usually saprophyte under certain conditions may become parasite.

23. facultative saprophyte- An organism that is usually parasite but may also live as a saprophyte.

24. gall- a swelling producing on a plant as a result of infection by certain pathogens.

25. gummosis- production of gum by plant tissue.

26. heterotrophic-  an organism depending on an outside source for organic nutrients.

27. hyperplasia-  excessive development due to increase in the number of cells.

28. hypertrophy-  excessive growth due to increase in size of cells.

29.immunity- the state of being exempted from infection by a given pathogen.

30. infection-  establishment of the pathogen in the host.

31. infections disease- a disease caused by a pathogen which can spread from a diseased to a healthy plant.

32. latent virus-  a virus that does not  induce symptoms in it’s host.

33. leaf mottling- a disease caused due to zinc deficiency specially in citrus sppp. In which new leaves develop inter-veinal chlorosis, get reduced in size, plant becomes bushy and rhe branches show die-back symptoms.

34.lesion- a localized area of discoloration , diseased tissue.

35. mildew­- a plant disease caused by a fungal in which  the mycelium and spores are seen as a whitish growth on the host surface.

36.mosiac- symptom of certain viral disease of the plants characterized by intermingled patches of normal and light green or yellowish color.

37. Mycorrhiza- symbiotic relationship between roots of higher plants and fungal mycelia which is essential for the growth of these plants.

38. necrosis- the death of cells or of tissues.

39.obigate parasite -  a parasite that in nature can grow and multiply only on living organisms.

40. parthenogenesis- formation of embryo without fertilization.

41. pathogen- an disease causing agent In plant.

42. plasmogamy- fusion of cytoplasms of two cells.

43. polymorphism-  having various forms in a life cycle. The rust fungus is allomorphic as it produce five different types of spores in it’s life-cycle.

44. pustule- small blister like elevation of epidermis.

45. quarantine­ control of export and import of plant to prevent spread of disease or pests.

46. race- a genetically distinct mating group within a species; also a group of pathogen with distinct pathological or physiological characteristics.

47. resistance- the ability of an organism to overcome, completely or partially the effect of a pathogen.

48. rickettsia like organism- RLOs a prokaryotic microorganism having a cell wall and obligate intra-cellular parasite.

49. ring spot- a circular chlorotic area with a green centre; symptom of many viral disease.

50. rot- the softening, discoloration and disintegration of a succulent plant tissue as a result pf fungal or bacterial infection.

51. russetting- brownish roughened areas on fruit skin produced as a result of excessive cork formation.

52. rust- a disease of grasses and other plants giving a rusty appearance to the plant and caused by uredinaless.

52. saprophyte- in organism which lives on dead and decaying organic matter.

53. scab- a rough, crust like diseased area on the surface of a plant organ. A disease in which such areas are formed.

54. scorch- burning of leaf margins as a result of infection or unfavorable environmental conditions.

55.smut- a disease caused by ustilaginaceae, characterized by masses of dark, powdery spores.

56. spot- disease symptom in which certain restricted tissue.

57. susceptibility- the inability of a plant to resist the effect of a pathogen.

58. susceptible- a plan t or species which is incapable of resisting the effect of a pathogen.

59. toxin- a compound produced by microorganisms and being toxic to a plant or animal.

60. vector- an insect able to transmit a pathogen.

61. vein banding- bands of green tissye along the veins while the tissue between the veins become chlorotic.

62. viroid- a naked nucleic acid which resembles virus but is devoid of protein coat.

63. wilt-  loss of rigidity and dropping of plant parts wholly or partially.

64. yellows-yellowing and stunting of host plant.