Diseases of Vegetable, Ornamental and Spice Crops

QUESTIONS

Q.No. 1. Tick the correct answer
1. Phytophthora spp. overwinter in soil as:

a) Oospore b) Chlamydospore c) Acervulus d) Perithecium

2. Infection of leaf blight and fruit rot takes place through

a) Oospores b) Conidia c) Rain splashed zoospores d) Chlamydospores

3. Symptoms of anthracnose and ripe fruit rot appear as:

a) Die-back b) Anthracnose c) Die-back and anthracnose and ripe fruit rot
d) None

4. Die-back is characterized by:

a) Necrosis of twigs b) Necrosis of twigs from tip to backwards
c) Necrosis of twigs from stem to new growth d) None

5. Anthracnose and ripe fruit rot of chilli appear on:

a) Immature fruits b) Mature green and red fruits
c) Newly formed fruits d) None

6. Perfect stage of Colletotrichum capsici is :

a) Diaporthe vexans b) Glomerella cingulata
c) Pseudoperonospora cubensis d) Ascochyta pisi

7. Spores of Colletotrichum capsici are produced in:

a) Acervulus b) Pycnidia c) Perithecia d) Cleistothecia

8. Cercospora leaf spot is also known as:

a) Birdseye spot b) Frogeye spot c) Buckeye spot d) None

9. Development of Cercospora leaf spot is more severe in:

a) High humidity and moderate temperature b) low humidity and moderate temperature
c) High humidity and high temperature d) Low humidity and low temperature

10. In powdery mildew disease of bell pepper, powdery growth appears on:

a) On under surface b) On upper surface c) On both surfaces d) None

11. Powdery mildew of bell pepper is caused by

a) Erysiphe cichoracearum b) Leveillula taurica c) Sphaerotheca fuliginea d) Erysiphe capsici

12. Xanthomonas campestris pv. vesicatoria is:

a) Gram –tive and rod shaped b) Gram + ve and rod shaped
c) Gram –tive, rod shaped with 4 polar flagella d) Gram – ve, rod shaped with round ends and single polar flagellum

13. Mosaic of bell pepper is transmitted by:

a) Aphid b) White fly c) Thrips d) Leaf hopper

14. Stem rot of bell pepper is caused by:

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

15. Soft rot of capsicum is caused by:

a) Erwinia carotovora sub.sp. carotovora b) Xanthomonas campestris pv. campestris
c) Erwinia campestris pv. campestris d) Bacillus subtilis

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

Q.No. 2. Fill in the blanks

1. Phytophthora leaf blight and fruit rot is important in those areas where --------------------- coincides with the onset of monsoon rains.
2. Due to the infection of leaf blight and fruit rot, ------------------------ leaf fall is the characteristic symptom.
3. Leaf blight and fruit rot is caused by two species of ----------------------------- .
4. Both species of Phytophthora survive in the form of -----------------------.
5. Temperature ranging from ----------------------- o C along with ----------------------------- RH favour leaf blight and fruit rot.
6. Symptoms of anthracnose and ripe fruit rot appear as ------------------------ and -------------------.
7. Anthracnose and ripe fruit rot appear only on ----------------------- fruits.
8. Spores of Colletotrichum capsici are produced in -----------------------------.
9. Cercospora leaf spot is also called as--------------------------- spot.
10. In powdery mildew of Capsicum, premature senescence of leaves results in ---------------------------.
11. Bacterial spot pathogen persists in ------------------------ and --------------------------------.
12. Leaf curl virus belongs to --------------------- group.
13. ------------------------------ is predominant vector of mosaic of capsicum.
14. Powdery mildew of capsicum is caused by ----------------.
15. Anthracnose of chilli and capsicum is caused by -----------------.
16. Leaf curl in chilli is caused by ----------------------------.
17. Bacterial spot in chili is caused by -------------------.
18. Temperature ranging from -----------o C along with --------- % humidity favour disease development Phytophthora leaf blight and fruit rot.
19. Sporangia of ----------------- requires free water for their germination.

Answers : 1) Fruiting 2) Premature 3) Phytophthora nicotianae, P.capsici 4) Oospores 5) 22 -25o C, high humidity (>80%) 6) small, circular, yellowish to pinkish, sunken spots on the skin of the fruits 7) fully mature and red ripe fruits 8) acervulus 9) frog eye 10) defoliation 11) plant debris, fruits 12) Bigeminivirus 13) Myzus persicae 14) Leveillula taurica 15 ) Colletotrichum capsici 16) Tobacco leaf curl virus (TLCV), 17) Xanthomonas campestris pv. campestris 18) 22-25 ºC and > 80 % 19) Phytophthora spp.

Subjective type questions:

1. Write down the symptoms and epidemiology of Phytophthora leaf blight and fruit rot of capsicum.
2. Write down the management strategies of following diseases:

a. Anthracnose of chilli
b. Powdery mildew of capsicum
c. Phytophthora leaf blight and fruit rot of capsicum

3. Describe in detail the symptoms and management strategy for viral diseases of chillies and bell pepper.