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Friday, January 29, 2016

 Nick Christians
January 29, 2016

Georgeanna Heitshusen leaves today for the Supper Bowl internship sponsored by the Toro company.  Georgie is the first female to win the internship.  This honor goes to one turf student each year in United States.  She is the 3rd ISU student in the last 5 years to be chosen for this honor.

Josh Lenz, a turf graduate student at ISU and former internship winner, is also at this year's Supper Bowl helping to prepare for the game.


 

 You can find a news clip on Georgie and the Internship at:

http://whotv.com/2016/01/28/super-bowl-internship-takes-root-for-isu-student/

Tuesday, December 8, 2015

DOLLAR SPOT TRIAL AT IOWA STATE-2015



Nick Christians
December 8, 2015
nchris@iastate.edu

The following is a report on a dollar spot trial conducted at the research station this past summer.  The primary objective of the work was to evaluate the effect of an experimental adjuvant on disease control, but there is a lot of good information comparing the different fungicides.  We had a great year for dollar spot at the station.


KALO FUNGICIDE/ADJUVANT TRIAL-2015

Nick Christians and Dan Strey
Iowa State University


Objective

To compare the control of Dollar Sport caused by the fungi Sclerotinia homeocarpa on creeping bentgrass turf with 7 commercial fungicides applied with and without Kalo’s  KA-9107 experimental adjuvant.  

Materials and Methods

The trial was conducted at the Iowa State University Horticulture research station near Gilbert, Iowa.  Plots were located on a mature stand of creeping bentgrass and were arranged in a randomized complete block design with 3 replications. Each plot measured 5 x 5 ft, for a total of 25 ft2 per plot. Bentgrass was a mixed sward of ‘1019’, ‘1020’, and ‘Penncross’ maintained at 0.5”.  Soil at the site was a 1:1:1 mix of sand:peat:soil with a particle size of 13.7% sand, 56.9% silt, and 29.5% clay.  Soil pH was 7.6 with soil P and K contents of 17 and 58 ppm, respectively.  Soil type was a Nicollet clay-loam (fine-loamy, mixed, mesic, Typic Hapluldoll). 

The full list of treatments appears in Table 1.  All products were applied through TeeJet 8002VS nozzles in a spray volume equivalent to 2 gallons/1000 ft2 powered by carbon dioxide supplying 40 pounds per square inch. The products were generally applied on 14 day intervals.
Results

The two week interval of application was too long to get satisfactory control of dollar spot with chlorothalonil (Table 2). The addition of the KA-9107 to chlorothalonil did provide numerically better control in most data collection dates.  These differences were significant on Sept. 2, Sept. 24, Oct. 2 and for the grand mean of all dates.   Fathom 14.3 MEC, Briskway, and Renown also provided less than desirable control. Control with Briskway was improved by KA-9107 on July 8 and July 27, as was the control with Renown.  The control with Fathom 14.3 MEC was improved by the adjuvant on August 25.  Emerald, Secure, and Velista were the most effective controls of dollar spot.   While at most dates, there was a numerical advantage to adding KA-9107 to these materials, there control was so effective, that none of these differences were significant.

Overall means comparing fungicides with adjuvant and those without adjuvant were calculated and orthogonal contrasts were performed to compare the means (Table 2) (Figure 1).  Significant improvement in activity of all fungicides that included KA-9107 were observed on July 8 and July 27.   The grand mean of all treatments over all dates showed a decrease of from 22 % dollar spot to 18 % dollar spot when KA-9107 was used as an additive.  The level of significance for this difference was 0.08.

It is apparent that KA-9107 can boost the activity of some fungicides for the control of dollar spot on creeping bentgrass turf.  Future studies could include the application of KA-9107 without a fungicide to determine if it provides any suppression on dollar spot development by itself.  It would also make sense to test the most effective materials with and without the adjuvant at longer intervals between treatments to determine if KA-9107 extends the activity of these products.

Table 1.  Treatments in the 2015 Kalo Fungicide/Adjuvant trial.




Product
Adjuvant
Product
Adjuvant
App
Trt #
Treatment
Rate (/1,000 ft²)
Rate (/1,000 ft²)
Rate (ml/25 ft²)
Rate (ml/25 ft²)
Interval


1
Control
-
-
-
-

2
Chlorothalonil
1.8 dry oz.
-
1.277 g
-
14 days
3
Chlorothalonil + adj
1.8 dry oz.
1.3 fl. oz.
1.277 g
0.96 ml
14 days
4
Emerald
0.13 dry oz.
-
0.092 g
-
14 days
5
Emerald + adj
0.13 dry oz.
1.3 fl. oz.
0.092 g
0.96 ml
14 days
6
Secure (Fluazinam)
0.5 fl. oz.
-
0.37 ml
-
14 days
7
Secure + adj
0.5 fl. oz.
1.3 fl. oz.
0.37 ml
0.96 ml
14 days
8
Fathom 14.3 MEC (propinozole)
0.5 fl. oz.
-
0.37 ml
-
14 days
9
(Fathom 14.3 MEC  + adj
0.5 fl. oz.
1.3 fl. oz.
0.37 ml
0.96 ml
14 days
10
Briskway (difenoconozole +     azoxystrogin)
0.5 fl. oz.
-
0.37 ml
-
14 days
11
Briskway + adj
0.5 fl. oz.
1.3 fl. oz.
0.37 ml
0.96 ml
14 days
12
Renown (chlorothalonil + azoxystrobin
4.0 fl. oz.
-
2.96 ml
-
14 days
13
Renown + adj
4.0 fl. oz.
1.3 fl. oz.
2.96 ml
0.96 ml
14 days
14
Velista (penthiopyrad)
0.5 dry oz.

0.355 g

14 days
15
Velista + adj
0.5 dry oz.
1.3 fl. oz.
0.355
0.96 ml
14 days









Table 2.  Data from 2015 Dollar Spot Trial.

% DOLLAR SPOT INFESTATION
TREATMENT
8-Jul
22-Jul
27-Jul
8-Aug
14-Aug
25-Aug
2-Sep
24-Sep
2-Oct
MEAN
1.  Control
68
68
85
49
38
32
19
42
24
47
2. Chlorothalonil 
25
57
75
54
52
83
82
33
15
53
3. Chlorthalonil + adj
13
52
70
30
37
73
75
15
6
41
4. Emerald
1
6
1
0
0
3
11
4
2
3
5. Emerald + adjuvant
0
2
0
1
1
0
3
1
1
1
6. Secure
0
1
1
1
2
6
13
3
0
3
7. Secure + adjuvant
0
1
2
2
0
4
9
4
0
2
8. Fathom 14.3 MEC
8
38
28
12
12
53
70
27
9
29
9. Fathom + adjuvant
3
32
21
6
6
29
67
24
10
22
10. Briskway
28
57
29
12
7
27
84
15
3
29
11. Briskway + adjuvant
11
37
10
4
4
25
77
18
5
21
12. Renown
33
53
64
14
8
45
72
14
6
34
13. Renown + adjuvant
14
52
52
24
15
60
83
30
6
37
  14. Velista
0
5
4
2
1
5
12
6
4
4
  15. Velista + adjuvant
0
2
1
1
0
2
7
5
1
2
LSD 0.05
16
21
12
24
26
16
10
15
8
12
ADJ VS NOADJ
0.02*
0.15
0.01**
0.37
0.57
0.16
0.10
0.77
0.34
0.08
MEAN ADJ
6
25
22
10
9
28
46
14
4
18
MEAN NOADJ
14
31
29
14
12
32
49
15
6
22