Diseases of Vegetable, Ornamental and Spice Crops

QUESTIONS

Q. No. 1. Tick the correct answer
1. Characteristic symptoms of Cercospora leaf spot include:

a) Spots with necrotic centre and reddish brown margin b) Spots with grayish centre c) Spots with white centre d) Spots with grayish centre and brown margin

2. Cercospora beticola conidia germinate best in the presence of :

a) Free water and high temperature b) Free water and low temperature c) Free water and moderate temperature d) Free water and 10-15o C temperature

3. Pre-requisite to Cercospora beticola sporulation is:

a) Low temperature b) High RH c) Low RH d) Low temperature and low RH

4.Cercospora leaf spot of beet can be limited by sprays of:

a) Bordeaux mixture b) Copper oxychloride c) Kocide d) Carbendazim

5. Severely powdery mildew infected leaves looks as they are dusted with:

a) Pigeon pea flour b) Maize Flour c) Rice flour d) Wheat Flour

6. Cleistothecia of Erysiphe betae contains:

a) 4-8 asci b) 2-3 asci c) 2-10 asci d) 8-18 asci

7. Erysiphe betae also overwinters in the form of:

a) Sclerotia b) Cleistothecia c) Pseudothecia d) Chlamydospores

8. Powdery mildew can be managed by sprays of :

a) Kocide b) Mancozeb c) Propineb d) Hexaconazole

9. Sclerotium root rot is caused by:

a) Sclerotinia sclerotiorum b) Macrophomina phaseolina c) Sclerotium rolfsii
d) Rhizoctonia solani

10. Sclerotium rolfsii survive in:

a) Seed b) Soil c) Plant debris d) None

11. Sclerotium rolfsii overwinters in soil in the form of:

a) Oospore b) Sclerotia c) Chlamydospore d) Conidia

12. Sclerotium root rot can be reduced with the application of:

a) Nitrogenous b) Phosphorus c) Potash d) Mixed fertilizer

13. The incidence of Sclerotium root is also reduced with the application of bioagent:

a) Pseudomonas flourescens b) Bacilus subtilis c) Trichoderma harzianum

d) Trichothecium roseum

14. Rhizomania disease of Beet root is caused by:

a) Fungi b) Bacteria c) Virus d) Phytoplasma

15. Beet Necrosis Yellow Vein virus belongs to which group:

a) Furovirus b) Potyvirus c) Carlavirus d) Tobamovirus

Answers:

1 a, 2 c 3 b 4 d 5 d 6 a 7 b 8 d 9 c 10 c 11 b 12 a 13 c 14 c 15 a

Q. No. 2. Fill in the blanks:

1. The conidia of Cercospora betae are -------------------, -------------------, ------------------- and ------------------.
2. --------------------- is essential prerequisite to sporulation of Cercospora betae.
3. Conidial germination of Cercospora betae is best in the presence of ------------------- water and---------------- temperature.
4. Cercospora leaf spot pathogen perpetuate in infected-------------------- as----------------- or on the ------------------.
5. The formation of first-------------------, later-------------------- mildew areas on both sides of the leaves characterize powdery mildew.
6. --------------------- develop as small dark round structures on the powdery mildew infected surface of the leaf.
7. Powdery mildew pathogen normally survives from one season to another in----------- state.
8. The virus responsible for Rhizomania is----------------------------.
9. Rhizomania virus is transmitted by------------------------------.
10. The infectivity of Beet Necrosis Yellow Vein Virus was retained with Polymyxa betae in----------------- and ----------------soil.
11. Varieties ------------------ and------------------- posses resistance to Rhizomania disease.
12. Soil inoculation with ---------------------------- also reduce the infection of Polymyxa betae.
13. Sclerotium rolfsii survive in soil in the form of-----------------------.
14. Powdery mildew of beet root can be effectively managed by sprays of----------------------, --------------------------------, --------------------------- and------------------------------- fungicides.
15. Bio-agents like----------------------- can be used in the management of Sclerotium root rot.

Answers

1 Hyaline, elongated, Filiform, multiseptate 2. High relative humidity 3. Free, moderate 4. Plant debris, mycelium, seed 5. White, grey-tan 6. Cleistothecium 7.Conidial 8. Beet Necrosis Yellow Vein Virus (BNYVV) 9. Polymyxa betae 10 Air, dry 11. Laetitia, Nagaiw 12. Trichoderma harzianum 13. sclerotia 14. benomyl, carbendazim, thiophanate- methyl, hexaconazole or difenoconazole 15. Trichoderma harzianum

Subjective type questions:

1. Write down the symptoms of the following diseases
a) Cercospora leaf spot
b) Powdery mildew
c) Sclerotium root rot
2. Describe in detail Rhizomania disease of beet root along with its management.
3. Write down the disease cycle, epidemiology and management of following diseases
a. Cercospora leaf spot b. Powdery mildew c. Sclerotium root rot