Thrips Management in Blueberries

1
Thrips Management in Blueberries Oscar E.
Liburd Entomology and Nematology Department
University of Florida
2
Background
Flower thrips, Frankliniella spp.

• Adults 1/16 of an inch
• Yellow-orange coloration
• Wide host range, rapid
• colonizers
• Multiple generations per year
• Travel along wind currents

3
Background - Thrips Lifecycle

Pupa non-feeding
Larval feeding
Male
Female

4
Flower-thrips species
97
1
Western
Florida flower thrips
1
1
Eastern
Other
5
Goals (2005)

• Track the movement of flower thrips into
  blueberry fields
• To correlate thrips population with blueberry
  flower
• development
• 3) To evaluate reduced-risk and conventional
• insecticides for control of thrips in
  blueberries

6
Tracking the movement of flower thrips into
blueberry fields

• 2 Farms were selected
• Each farm had 49 sampling stations (white sticky
  traps)
• Traps were collected every other day for 25 days
• Correlated the number of thrips caught on traps
  with flower development

7
Relationship between flower development and
movement of thrips
40 - 50
0 - 5
Day 7 Max 25 thrips/trap
Day 3 Max 5 thrips/trap
8
Movement of thrips into blueberry fields
80 90
70 - 80
Day 16
190 thrips/trap
Fruit formation
Day 21
Day 13
35 thrips/trap
100 thrips/trap
9
Results
Size of thrips populations in relation to flower
phenology
Percentages of opened flowers
10
70
20
90
1
R 0.9908 F 107.8 df 3,9 P lt 0.0001
10
Questions
Q. When do I spray for thrips? Ans. It depends
on several factors including history of farm If
you have a history of high thrips population you
should begin to spray when 5 of the flowers have
opened If your farm usually experience low
thrips population, you can wait until 50 of the
flowers have opened to begin your spraying
program Q. What should I spray?
11
Pesticide efficacy results
2004
2005
12
Effect of SpinTor on thrips population over 48
hours
13
Question

• What is the relationship between thrips numbers
• and injury?

14
Thrips Injury
Hand pollination
Thrips release
Flower protection
Fruit formation counting
Flower protection
15
Thrips Injury fruits
0 thrips /flower
16
Thrips Injury fruits
Oviposition Injury (5 to 10 thrips / flower)
17
Thrips Injury Fruit dehydration
20 thrips /flower
18
Thrips Injury
Average S.E.M.
19
Thrips Injury oviposition
Style
Petals

• 2 blueberry
  species in FL
• 250 flower per species
• 27C and 80 RH
• 15 days

Fruits
Ovaries
20
Thrips Injury oviposition
a
b
c
c
F 19.16 df 3,46 P lt 0.001
21
Conclusions

• Flower-thrips reduce the quality and quantity of
  the blueberries
• 7 days after bloom the initiation of hot-spots
  are defined
• Thrips are present in blueberry fields for about
  25 days from flower opening to petal fall
• In cases where there are high populations of
  thrips, insecticides could be more effective if
  applied when the hot-spots are defined (5-10 days
  after bloom)
• Assail, Diamond and Actara have shown to be
  significantly more effective than Malathion in
• controlling thrips population in blueberry
  fields

22
Acknowledgements

• Florida Blueberry Growers Association (FBGA)
• Michigan Blueberry Growers Association (MBG)
• Florida and Georgia blueberry growers
• Southern Region EPA grant X8-96424405-0
• Small Fruit and Vegetable Lab at UF