Arthropod Management Tests 2013, Vol. 38
doi: 10.4182/amt.2013.E34
(E34)
ONION: Allium cepa L., ‘Sedona’
ONION THRIPS CONTROL, 2012
Adam M. Byrne
Michigan State University
243 Natural Science Building
East Lansing, MI 48824
Phone: (517) 432-0900
Fax: (517) 353-4354
E-mail: [email protected]
Zsofia Szendrei
E-mail: [email protected]
Onion thrips: Thrips tabaci (Lindeman)
Onion thrips is the most important insect pest of onions in the Great Lakes region. Adult and nymph feeding cause’s
significant damage and they are a vector of Iris yellow spot virus, a disease that can reduce yield.
Fifteen insecticide treatments and an untreated check (Table 1) were tested for onion thrips control in a commercial onion
field in Stockbridge, MI. ‘Sedona’ onions were planted in late Apr into three-row beds, with 6 inch row spacing and beds
25 inches apart. Treatments were replicated four times in a RCB design. Plots were 15 ft long. Some treatments were
applied weekly and others based on thresholds (3 thrips/leaf for Radiant SC; 1 thrips/leaf for all other compounds). All
treatments included the surfactant Dyne-Amic at 0.5% v/v. Foliar treatments were applied using a single-nozzle hand-held
boom (50 gpa and 40 psi). Plots were initially sprayed on 20 June when there were about 4 leaves/plant and the density of
onion thrips averaged 5.5 thrips/plant. Treatments following a weekly spray program were conducted over an eight-week
period (20 Jun to 8 Aug), whereas some threshold-based treatments were continued for an additional two weeks.
Treatments 9 & 10 both required additional applications on 17 & 24 Aug (Radiant @ 10 fl oz/acre and Lannate @ 3 pt/acre,
respectively, for treatment 9; two applications of Lannate @ 3 pt/acre for treatment 10). Treatment 12 did not require any
further applications over the extended 2-wk period, resulting in only six insecticide applications for the season. Post-spray
counts of thrips on 10 random plants/plot were made weekly. Plots were visually rated for thrips damage on 17 & 24 Aug
2012 using a scale from 1 to 10 (1 = complete devastation by thrips (leaves all white instead of green), 10 = no detectable
thrips feeding); a rating of 8 or above would be considered commercially acceptable. Onions in each plot were harvested
and graded as jumbo (≥3 inch diameter), standard (2.0 to 2.9 inch diameter), and boiler (1.5 to 1.9 inch diameter), and the
number in each class was recorded and weighed; small or misshapen bulbs were discarded. Data was log (x+1) transformed
prior to analysis. Analysis of variance was used for data analysis and Tukey means separation was used to compare
treatment means (P < 0.05).
All treatments resulted in a significantly lower seasonal mean number of thrips relative to the untreated check (Table 2).
Treatments with Movento 240 SC applied during the first two weeks were the most effective. Alternatively, those
treatments without Movento 240 SC in their rotation resulted in the highest mean number of thrips/plant. We also compared
weekly and threshold-based spray programs. Not surprisingly, programs with weekly insecticide applications resulted in a
lower seasonal mean number of thrips/plant. However, threshold-based programs were able to reduce the number of overall
insecticide applications without any significant yield reduction. All treatments resulted in a significantly higher visual
rating and greater mean yield, compared to the untreated control. All treatments, except 14, resulted in significantly more
jumbo bulbs, while all treatments, except 5 & 14, had a significantly greater mean weight of jumbo bulbs, compared to the
untreated control. The number of new and effective compounds for thrips control is promising, but growers need to remain
committed to resistance management practices to help assure that these compounds will remain effective into the future.
This research was supported by industry gift of pesticide funding.
1
Arthropod Management Tests 2013, Vol. 38
doi: 10.4182/amt.2013.E34
Table 1.
Trt
20 Jun
28 Jun
5 Jul
11 Jul
18 Jul
25 Jul
1 Aug
8 Aug
1
Benevia 10 OD
13.5 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Torac 15 EC
24 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Benevia 10 OD
13.5 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Torac 15 EC
24 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Benevia 10 OD
13.5 fl oz/A
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Agri-Mek SC
3 fl oz/A
Torac 15 EC
24 fl oz/A
Agri-Mek SC
3 fl oz/A
Agri-Mek SC
3 fl oz/A
Movento 240 SC
5 fl oz/A
Benevia 10 OD
13.5 fl oz/A
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Agri-Mek SC
3 fl oz/A
Torac 15 EC
24 fl oz/A
Agri-Mek SC
3 fl oz/A
Agri-Mek SC
3 fl oz/A
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Benevia 10 OD
13.5 fl oz/A
Radiant SC
8 fl oz/A
Radiant SC
8 fl oz/A
Radiant SC
8 fl oz/A
Torac 15 EC
24 fl oz/A
Torac 15 EC +
Lannate LV
24 fl oz + 3 pt/A
Radiant SC
8 fl oz/A
Radiant SC
8 fl oz/A
Radiant SC
8 fl oz/A
Benevia 10 OD
13.5 fl oz/A
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Radiant SC
8 fl oz/A
Radiant SC
8 fl oz/A
Radiant SC
8 fl oz/A
Radiant SC
8 fl oz/A
Radiant SC
8 fl oz/A
Benevia 10 OD
13.5 fl oz/A
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Radiant SC
8 fl oz/A
Radiant SC
8 fl oz/A
Benevia 10 OD
20.5 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Benevia 10 OD
20.5 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Movento 240 SC
5 fl oz/A
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Benevia 10 OD
13.5 fl oz/A
Radiant SC
8 fl oz/A
Radiant SC
8 fl oz/A
Radiant SC
8 fl oz/A
Torac 15 EC
24 fl oz/A
Torac 15 EC +
Lannate LV
24 fl oz + 3 pt/A
Radiant SC
10 fl oz/A
Agri-Mek SC
3 fl oz/A
Radiant SC
7 fl oz/A
Agri-Mek SC
3 fl oz/A
Radiant SC
10 fl oz/A
Benevia 10 OD
20.5 fl oz/A
Benevia 10 OD
20.5 fl oz/A
Lannate LV
3 pt/A
Radiant SC
7 fl oz/A
Lannate LV
3 pt/A
Radiant SC
10 fl oz/A
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Radiant SC
7 fl oz/A
Lannate LV
3 pt/A
2
3
4
5
6
7
8
9*
10*
11
12*
13
14*
15
Radiant SC
10 fl oz/A
Agri-Mek SC
3 fl oz/A
Agri-Mek SC
3 fl oz/A
Agri-Mek SC
3 fl oz/A
Agri-Mek SC
3 fl oz/A
Agri-Mek SC
3 fl oz/A
Agri-Mek SC
3 fl oz/A
Agri-Mek SC
3 fl oz/A
Agri-Mek SC
3 fl oz/A
Agri-Mek SC
3 fl oz/A
Radiant SC
7 fl oz/A
Agri-Mek SC
3 fl oz/A
Radiant SC
10 fl oz/A
Benevia 10 OD
20.5 fl oz/A
Benevia 10 OD
20.5 fl oz/A
16
*insecticides applied based on thresholds (3 thrips/leaf for Radiant, 1 thrips/leaf for all other products)
2
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Lannate LV
3 pt/A
Arthropod Management Tests 2013, Vol. 38
doi: 10.4182/amt.2013.E34
Table 2.
Mean no. onion thrips/plant and corresponding application date
Treatment
20 Jun
28 Jun
5 Jul
11 Jul
18 Jul
25 Jul
1 Aug
8 Aug
1
Benevia
9.7ab
Movento
14.1b
Movento
10.0ab
Movento
11.1b
Torac
3.9a
Movento
11.6ab
Movento
10.9ab
Movento
11.8b
Benevia
8.6ab
Movento
8.6ab
Movento
13.4b
Movento
11.3b
Movento
9.8ab
Lannate
10.2ab
Lannate
7.8ab
15.5b
Benevia
8.1a
Movento
5.1a
Movento
4.7a
Movento
6.2ab
Torac
6.1a
Movento
6.1a
Movento
6.0a
Movento
6.9ab
Benevia
6.8a
Movento
5.1a
Movento
6.8ab
Movento
5.3a
Movento
4.1a
Lannate
10.2ab
Lannate
14.0bc
17.3c
Movento
46.1d
Benevia
2.0ab
Lannate
2.0a
Lannate
2.7abc
Agri-Mek
35.7d
Torac
2.4abc
Agri-Mek
2.7abc
Agri-Mek
3.4abc
Lannate
10.3ab
Lannate
20.9bc
Benevia
14.2ab
Radiant
13.3ab
Radiant
66.6e
Radiant
19.8bc
Torac
10.4ab
Torac + Lannate
15.8abc
35.2d
Movento
17.5cde
Benevia
6.1a
Lannate
9.6bcd
Lannate
7.4ab
Agri-Mek
23.2e
Torac
7.6ab
Agri-Mek
9.8abcd
Agri-Mek
16.9bcde
Radiant
17.5de
4.7bc
Agri-Mek
3.1abc
12.7bcde
Agri-Mek
8.8abcd
13.6bcde
Agri-Mek
8.8abc
Agri-Mek
27.2e
Agri-Mek
21.9e
66.9f
Radiant
9.3ab
Radiant
21.4bc
Radiant
8.7ab
Benevia
6.6a
Lannate
12.1ab
Lannate
21.2ab
Radiant
22.6bc
Radiant
13.6ab
Lannate
16.3ab
Radiant
24.5bc
Lannate
13.3ab
Radiant
7.6ab
Lannate
8.6ab
Lannate
11.6ab
Lannate
21.6abc
44.2c
Radiant
5.2a
Radiant
7.1a
Radiant
4.7a
Benevia
9.1a
Lannate
7.0a
Lannate
5.2a
Radiant
3.4a
Radiant
2.9a
Lannate
7.2a
Radiant
5.9a
Lannate
8.2ab
4.6c
Agri-Mek
3.3abc
Agri-Mek
52.1de
Agri-Mek
49.0de
76.9e
Lannate
11.2a
Lannate
39.8b
Benevia
22.8abcd
Radiant
20.3ab
Radiant
27.7abcd
Radiant
21.6abc
Torac
15.1ab
Torac + Lannate
15.8ab
Radiant
48.0c
Agri-Mek
35.1b
Radiant
22.7abc
Agri-Mek
23.0abcd
Radiant
8.7a
Benevia
19.4a
Benevia
36.1b
54.1d
2
3
4
5
6
7
8
9*
10*
11
12*
13
14*
15
16
57.8e
Agri-Mek
49.7de
Radiant
19.3bc
Agri-Mek
44.3de
Radiant
7.4a
Benevia
26.8cd
Benevia
42.1de
142.3f
*insecticides applied based on thresholds (3 thrips/leaf for Radiant, 1 thrips/leaf for all other products)
Means within columns not followed by the same letter are significantly different (Tukey’s HSD; p=0.05)
3
5.0ab
Lannate
5.3a
Lannate
3.9a
Lannate
5.4a
28.2b
Seasonal Mean
Yield (cwt/acre)
14.7bc
747.2a
14.6abc
756.8a
9.6ab
747.0a
9.6ab
725.6a
22.8ef
715.6a
11.9abc
809.8a
10.1abc
715.9a
10.9abc
733.7a
24.7ef
712.7a
18.3bcd
709.5a
11.9bc
800.3a
13.9cde
716.9a
7.0a
751.8a
21.0def
695.9a
24.7f
55.7g
755.0a
522.6b