1. University of Florida-IFAS Tropical Research and Education Center,
Chilli Thrips, Scirtothrips dorsalis Hood: A Serious Threat to Vegetables, Fruits and Ornamentals in the Western Hemisphere
Dakshina R. Seal
University of Florida-IFAS
Tropical Research and Education Center,
Homestead, Florida

2. OUTLINE OF THE TALK Introduction
Determination of Distribution in Caribbean
Spatial patterns of distribution
Control of S. dorsalis using chemicals
Effect of chemicals on ladybugs
Potentiality of minute pirate bugs in controlling S. dorsalis using the reference of T. palmi
Out-reaching activities with CAPS and School students in detecting S. dorsalis in South Florida
Acknowledgement
Question-Answer

3. INTRODUCTION Biology Synonyms Host plants Disease transmission
Geographical distribution

4. Biology
Chilli thrips occurs in tropical, subtropical and temperate countries
It thrives in 25o – 30oC
Preoviposition period 3-5 d
Female oviposits 8-12 eggs/day
eggs/female
Development period d

5. New Pest to the Western Hemisphere
Synonyms:
Castor thrips, Asam thrips, Berry
thrips or Yellow tea thrips,
Strawberry thrips
Preferred Scientific Name:
Scirtothrips dorsalis Hood 1919
Other Scientific Names
Anaphothrips andreae Karny Heliothrips minutissimus Bagnall Neophysopus fragariae Girault Scirtothrips andreae (Karny) Scirtothrips fragariae (Girault) Scirtothrips minutissimus (Bagnall) Scirtothrips padmae Ramakrishna 1942
Host Plants:
Over 112 host plants currently known, many are crop hosts – banana, beans, corn, citrus, cotton, cocoa, eggplant, grapes, kiwi, litchi, longan, mango, peach, peanut, peppers, soybean, tea, tobacco, tomato, etc. ,

6. Other names
French Thrips jaune du theier
Germany Nordindischer Tee-Blasenfuss
Japan tya-na-kiiro-azamiuma

7. Host Plants:
Over 112 host plants currently known, many are crop hosts – banana, beans, corn, citrus, cotton, cocoa, eggplant, grapes, kiwi, litchi, longan, mango, peach, peanut, peppers, soybean, tea, tobacco, tomato, etc.
Over 112 host plants curre

8. DISEASE TRANSMISSION Bud Necrosis Disease (BND) in peanuts
It is a weak vector of Tomato Spotted Wilt Virus (TSWV).
S. dorsalis is also a vector of Yellow Spot Virus (YSV) on ground nut.
It has been reported to cause Tospovirus
Peanut Chlorotic Fan-spot Virus.
Bacterial Leaf Spot and Bunchy Top diseases are also vectored by S. dorsalis.
It often causes chilli leaf curl (CLC) due to heavy larval feeding.

9. CLC
St. Vincent
Israel

10. CLC in a scotch bonnet field

11. Damaged calyx due to S. dorsalis

12. Geographical Distribution
Back to list of insects
                                                                                                         
Geographical Distribution
Bangladesh
India
Pakistan
China
Indonesia
Malaysia
Phlippines
Sri-Lanka
Thiland
South Africa
Ocenia
Old World Distribution:
Japan, China, India, Pakistan, Taiwan, Korea, Thailand, Africa, and Australia

13. Distribution in Western Hemisphere
Since 1984, USDA-APHIS inspectors at various ports of entry have reported S. dorsalis 89 times on imported plant materials belonging to 48 taxa (USDA 2003). Most commonly the pest was associated with cut flowers, fruits and vegetables.
In 2003, shipments of peppers from St. Vincent and St. Lucia inspected in Miami, showed the presence of S. dorsalis. This was the first indication of this pest in the Western Hemisphere.
Skarlinsky (2003) surveyed and found S. dorsalis on pepper crops at multiple farm sites in St. Vincent.
Therefore an additional survey was conducted to determine the host range, distribution, and impact of S. dorsalis was initiated with the support of both Ministries of Agriculture.

14. 15 Sites visited
62 Samples collected

15. Geographical distribution of Scirtothrips dorsalis by agricultural district in Saint Lucia.
No. locations
sampled
Total no. samples in all locations
Percent samples with S. dorsalis1
Total no.
S. dorsalis adults collected 1 * 2 3 4 12
16.7 (2) 30
36.7 (11) 29 5 6 16
68.7 (11)
201 7
25.0 (1) 8
* Not sampled
1 Values inside parenthesis indicate total number of samples with adult S. dorsalis

16. No. samples with S. dorsalis
Host plant distribution of Scirtothrips dorsalis in St Lucia.
Host plant
Total no. samples
No. samples with S. dorsalis
Percent samples with S. dorsalis
Pepper 21 11
52.4
Eggplant 15 6
40.0
Cucumber 5
45.5
Squash 7
Pigweed (Amaranthus sp) 2 1
50.0
Tomatoes
Cantaloupe
Ornamental
100
Watermelon
Zucchini

17. Numbers of Scirtothrips dorsalis and percentage of total thrips collected on various host plants in St Lucia.
Host plant
Total no. samples
Total no. adult S. dorsalis in samples
Total no. other adult thrips
S. dorsalis percent of total thrips collected
Pepper 21 83
157
34.6
Eggplant 15 9
120
7.0
Cucumber 11
128
656
16.3
Squash 7 16
Pigweed
(Amaranthus sp) 2 1
6.3
Tomatoes
Cantaloupe
Ornamentals 4 44
8.3
Watermelon
Zucchini 13 24
35.1

18. Distribution of Scirtothrips dorsalis among pepper varieties sampled on St. Lucia.
Pepper cultivar
Total no. samples
Total no. adult S. dorsalis in all samples
Total no. other adult thrips
S. dorsalis percent of total thrips collected
Scotch Bonnet 9 20 51
28.2
Bell pepper 5 13
Habanero 19 35
35.2
West Indies Red 2 44 58
43.2
Serrano 1

19. 35 Sites visited
123 samples collected

20. Geographical distribution of Scirtothrips dorsalis by agricultural districts in St. Vincent.
No. locations
sampled
Total no. samples in all location
Percent samples with S. dorsalis1
Total no. S. dorsalis adults collected 1 4 17
64.7 (11) 33 2 3 14
28.5 (4) 5 4E 25
52.0 (13)
135 4W 6 12
16.7 (2) 15
40.0 (2)
33.3 (1) 7 8 20
50.0 (10) 27 24
33.3 (8) 13
1Values inside parenthesis indicate total numbers of samples with adult S. dorsalis

21. Host plant distribution of Scirtothrips dorsalis in St. Vincent.
Numbers of samples/crop
Numbers of samples with
S. dorsalis
Percent samples with S. dorsalis
Pepper 63 38
60.3
Eggplant 20 4
20.0
Watermelon 8 2
28.5
Pumpkin 7
Tomato 6 1
16.7
Okra 5 3
60.0
Cucumber
Cantaloupe
Bean
33.3
Pigweed (Amaranthus sp.)

22. Numbers of Scirtothrips dorsalis and percentage of total thrips collected on various host plants in St. Vincent.
Host plant
Total no. samples
Total no. adult S. dorsalis in all samples
Total no. other adult thrips
S. dorsalis percent of total thrips collected
Pepper 63
198
650
23.3
Eggplant 20 5
187
2.6
Watermelon 8 12
305
3.8
Pumpkin 7 38
15.6
Tomato 6 1 16
5.9
Okra 40
14.9
Cucumber
160
Cantaloupe 3
168
Pigweed 2 55
Bean
170
1.2

23. Total no. adult S. dorsalis in all samples
Distribution of Scirtothrips dorsalis among pepper varieties sampled on St. Vincent.
Pepper cultivar
Total no. samples
Total no. adult S. dorsalis in all samples
Total no. other adult thrips
S. dorsalis percent of total thrips collected
West Indies Red 38 77
346
18.2
Habanero 13 50
135
37.0
Scotch Bonnet 8
116
203
27.0
Bell pepper 3 66 68
49.3
Santa Fe Grande 1
11.1
Within plant distribution of Scirtothrips dorsalis in pepper plants from selected farms in St. Vincent.
Pepper cultivar
Number of S. dorsalis adults collected
Leaves
Flower
Fruit
West Indies Red 2 1 5
Scotch Bonnet

24. Summary on Distribution
The above information indicate that S. dorsalis has established in St. Lucia and St. Vincent.
Various crops in various locations have been infested with S. dorsalis.