QUESTIONS

QUESTIONS

Q.No. 1. Tick the correct answer:
1. Plasmodiophora brassicae causes:
a) Bulb root b) Club root c) Root rot d) Collar rot
2. Plasmodiophora brassicae survives in soil in the form of :
a) Oospore b) Resting spore c) Chlamydospore d) Perithecium
3. Resting spores of Plasmodiophora brassicae are disseminated in field by:
a) Irrigation water b) Moist air c) Wind current d) Rain splashes
4. Club root is more serious in:
a) Alkaline soil b) Neutral soil c) Acidic soil d) None
5. Downy mildew of crucifers is caused by:
a) Peronospora destructor b) Peronospora parasitica
c) Peronospora cubensis d) Bremia lactucae
6. Infection of downy mildew is favoured by:
a) Low temperature and high humidity b) High temperature and high humidity c) Low temperature and low humidity d) High temperature and low humidity
7. Optimum temperature for Peronospora parasitica conidial germination is
a) 10-15o C b) 8-15o C c) 8-12 o C d) 10-20o C.
8. Alternaria leaf spot in cabbage and cauliflower is caused by:
a) Alternaria brassicicola b) Alternaria brassicae c) A. brassicicola and A. brassicae d) A. solani
9. The conidial beak is bigger in case of:
a) Alternaria brassicae b) Alternaria brassicicola
c) Alternaria raphani d) Alternaria alternata
10. Alternaria leaf spot pathogens overwinter in:
a) Plant debris b) Infected seed c) Cruciferous weeds d) All of these
11. Alternaria leaf spots can be managed effectively by sprays of :
a) Carbendazim b) Benomyl c) Thiophenate methyl d) Mancozeb

Answers
1b 2 b 3 a 4 c 5 b 6 a 7 c 8 c 9 a 10 d 11 d

Q.No. 2. Fill in the blanks
1. Club root is also known as ---------------------------- disease.
2. In club root , underground parts are------------------------.
3. In club root, malformation occurs in ------------------, ---------------------- and ---------------- roots.
4. Plasmodiophora brassicae is --------------------------, --------------------------- and ----------------- fungus.
5. The resting sporangia of Plasmodiophora brassicae are ---------------------, -------------------- and---------------------------spiney.
6. Resting spores of Plasmodiophora brassicae are disseminated in soil by ------------------ and -------------------- operations.
7. Favourable climate for development of club root includes ----------------- and ---------------- alongwith------------- soils.
8. Downy mildew fungus is an ---------------------- parasite.
9. Condiophores of downy mildew fungi are------------------------ branched.
10. Downy mildew pathogen perennates as --------------------.
11. Downy mildew fungus in association with-------------------------- induce malformed inflorescence.
12. Leaf spots incited by -------------------- are bigger and dark brown in colour.
13. Alternaria leaf spot in radish is caused by --------------------.

Answers: 1. Finger and Toe 2. Hypertrophied, 3. Primary, secondary, tertiary, 4. Biotroph, Endocellular, Plasmoidal 5. Spherical, uninucleate, minutely 6. Water, cultural 7. Cool, wet, acidic 8. Obligate 9. Dichotomously 10. Oospores 11. Albugo candida 12. Alternaria brassicicola 13. Alternaria raphani

Subjective type questions:
1. Write down the causal organism and characteristic symptoms of following diseases:
a. Club root of crucifers
b. Downy mildew of crucifers
2. Write down the disease cycle and epidemiology of following disease:
a. Downy mildew of crucifers
b. Club root of crucifers
Last modified: Thursday, 1 March 2012, 10:04 AM