Q.No. 1. Tick the correct answer:
1. ā€˜Vā€™ shaped lesion appear on leaves due to infection of:
a) Soft rot b) Black rot c) Stalk rot d) Downy mildew
2. Black rot is caused by:
a) Xanthomonas campestris pv. campestris b) Xanthomonas campestris pv. vesicatoria
c) Xanthomonas campestris pv. pruni d) Xanthomonas campestris pv. pisi
3. Extracellular polysaccharide produced by Xanthomonas is called:
a) Xanthan b) Xanthin c) Xanthum d) None of these
4. Black rot pathogen is :
a) Externally seed borne b) Internally seed borne c) Air borne d) None
5. Black rot pathogen enters in leaves through:
a) Stomata b) Hydathodes c) Lenticels d) Nectries
6. Optimum temperature for black rot development is:
a) 20-25o C b) 26.5-30o C c) 20-25o C
7. Hot water seed treatment for the control of black rot is done at:
a) 52o C b) 50o C c) 48o C d) 54o C
8. Cauliflower mosaic virus is transmitted by :
a) Aphid b) Whitefly c) Thrips d) Leaf hopper
9. Aphid vectors can be effectively managed by sprays of:
a) Endosulphan b) Malathion c) Metasystox d) Omite
10. Cauliflower mosaic virus belongs to which group:
a) Tobamovirus b) Gemini virus c) Begamovirus d) Caulimovirus

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

Q. No. 2. Fill in the Blanks:
1. Xanthomonas campestris pv. campestris produces a yellowish extracellular polysaccharide called as ----------------------------------- on medium containing glucose.
2. The genome of cauliflower mosaic virus consists of unipartite ---------------------- DNA.
3. Cauliflower mosaic Virus belongs to ------------------ group.
4. Ring spot in crucifers is caused by --------------------.
5. Curd rot of caulifloweris caused by ---------------------.
6. Black rot pathogens overwinters in -------------- and -----------.
7. Hot water seed treatment is recommended for the management of -----------------.

Answers: 1. Xanthan 2. Double stranded.3 caulimovirus (CaMV) group 4. Mycosphaerella brassicicola 5. Erwinia caratovora subsp. carotovora 6. infected seed, diseased plant debris, cruciferous weeds 7. Black rot

Q.No. 3 Subjective type questions:

1. Write down the causal organism and characteristic symptoms of following diseases:
a. Stalk rot of crucifers
b. White rust of crucifers
2. Write down the management practices for the following diseases:
a. Stalk rot of cabbage
b. Black rot of cabbage and cauliflower
c. White rust of crucifers
3. Write down the disease cycle and epidemiology of following disease:
a. White rust of crucifers
Last modified: Thursday, 1 March 2012, 10:11 AM