Objective:       

To evaluate the efficacy of Salicylate for the control of OWBM in susceptible and resistant spring wheat cultivars.          

Materials and Methods:

Spring wheat varieties containing the Sm1 gene for resistance to the orange wheat blossom midge are available to aid in their control.  However, some damage is incurred prior to the synthesis of the active compound.  This study was designed to determine if treatment with salicylate prior to larval feeding could upregulate the Sm1 gene and shorten the lag phase.  This study was established as a split plot design with three replications. Egan, a cultivar with resistance to the OWBM, and McNeal, a non-resistant cultivar were the whole plot treatments.  Salicylate was applied to both varieties at three rates and at three wheat growth stages.  Salicylate was applied at 0, 21, and 42 g ai/A when wheat was at the late boot stage, 50% headed, and 50% flowering growth stages.

Results:           

The study site experienced severe drought and low midge pressure.  As a result, any treatment effects that might have been present were largely masked by these environmental conditions. However, a few treatment effects were detected, and were largely associated with the differences between the two spring wheat varieties. Spring wheat yields averaged 23.6 bu/A, with McNeal producing slightly higher yields then Egan (24.0 and 23.2 bu/A, respectively).  Egan had greater protein and higher falling numbers, but McNeal had higher test weight and greater thousand kernel weight.  There were trends in the data which indicated a slight reduction in height, yield and test weight as rates of salicylate increased (Pr>F 0.4162, 0.1139, and 0.0519, respectively), while protein tended to increase (Pr>F=0.1148). However, the timing of salicylate treatments had no impact on any of the variables measured.

Summary:       

Record breaking drought and low midge populations prevented an accurate assessment of salicylate for improving crop resistance against the wheat midge.

 

Table 1. Materials and Methods - Sm1 Salicylate   
Seeding Date: 5/6/2015 Harvest Date: 8/12/2015
Julian Date: 125 Julian Date: 224
Seeding Rate: 80 lb/A Soil Type: Somers Silty Clay Loam
Previous Crop: Spring Wheat Fertilizer (PP): 23-55-30-22
Tillage: Conventional Fertilizer (TD): 1.4Zn-200N
Irrigation: None Pesticide: None
PP: pre-plant, TD: top dress   

 

Table 2. Main effect of application timing        
  HT LOD YLD¹ PRO² TWT¹ TKW¹ FN OWBM
  in % bu/A % lb/bu g sec no/ spk
Late Boot 21.1 0.0 23.5 17.4 53.5 24.4 521.2 0.0
50% Heading 31.9 0.0 23.5 17.6 53.6 24.8 526.7 0.0
50% Flowering 20.8 0.0 23.9 17.3 53.9 25.1 526.5 0.0
LSD ns ns ns ns ns ns ns ns
Pr>F 0.4284 1.0000 0.9314 0.7382 0.5950 0.4983 0.6398 0.7849
 HT; height, LOD: lodging, YLD: yield, PRO: protein, TWT: test weight, TKW: thousand kernel weight, FN: falling number, OWBM: orange wheat blossom midge, ns: nonsignificant         
¹adjusted to 13% moisture,  ²adjusted to 12%        

 

Table 3. Main effect of treatment rate        
  HT LOD YLD¹ PRO² TWT¹ TKW¹ FN OWBM
  in % bu/A % lb/bu g sec no/ spk
Untreated Check 31.5 0.0 24.5 17.1 54.0 25.0 524.9 0.0
Salicylic acid 21 g ai/A 21.3 0.0 23.6 17.5 53.6 24.5 526.1 0.0
Salicylic acid 42 g ai/A 21.0 0.0 22.7 17.7 53.5 24.8 523.4 0.0
LSD ns ns ns ns 0.4 ns ns ns
Pr>F 0.4162 1.0000 0.1139 0.1148 0.0519 0.4177 0.9195 0.6380
HT; height, LOD: lodging, YLD: yield, PRO: protein, TWT: test weight, TKW: thousand kernel weight, FN: falling number, OWBM: orange wheat blossom midge, ns: nonsignificant                 
¹adjusted to 13% moisture,  ²adjusted to 12%           

 

Table 4. Main effect of variety        
  HT LOD YLD¹ PRO² TWT¹ TKW¹ FN OWBM
  in % bu/A % lb/bu g sec no/ spk
Egan 20.7 0.0 23.2 18.0 53.0 23.7 533.1 0.0
McNeal 28.6 0.0 24.0 16.8 54.4 25.8 516.6 0.0
LSD ns ns 0.7 0.4 0.3 0.6 10.8 ns
Pr>F 0.2797 1.0000 0.0205 0.0001 0.0001 0.0001 0.0048 0.1510
HT; height, LOD: lodging, YLD: yield, PRO: protein, TWT: test weight, TKW: thousand kernel weight, FN: falling number, OWBM: orange wheat blossom midge, ns: nonsignificant        
¹adjusted to 13% moisture, ²adjusted to 12%        

 

Table 5. Effect of application timing and rate of treatment        
  HT LOD YLD¹ PRO² TWT¹ TKW¹ FN OWBM
  in % bu/A % lb/bu g sec no/ spk
Check
Late Boot 21.2 0.0 25.3 17.0 53.8 24.8 523.2 0.0
50% Heading 52.8 0.0 24.6 17.1 54.1 25.3 523.1 0.0
50% Flowering 20.5 0.0 23.8 17.1 54.0 25.0 528.3 0.0
Salicylic acid 21 g ai/A
Late Boot 21.3 0.0 23.3 17.3 53.6 24.3 517.9 0.0
50% Heading 21.5 0.0 24.0 17.6 53.4 24.3 530.6 0.1
50% Flowering 21.2 0.0 23.7 17.5 53.8 24.8 529.8 0.1
Salicylic acid 42 g ai/A
Late Boot 20.8 0.0 22.0 17.9 53.1 23.9 522.3 0.0
50% Heading 21.3 0.0 21.9 17.9 53.4 24.8 526.5 0.0
50% Flowering 20.8 0.0 24.1 17.2 54.0 25.6 521.5 0.1
LSD ns ns ns ns ns ns ns ns
Pr>F 0.4536 1.0000 0.4226 0.6385 0.4195 0.5898 0.8834 0.3361
HT: height, LOD: lodging, YLD: yield, PRO: protein, TWT: test weight, TKW: thousand kernal weight, FN: falling number, OWBM: orange wheat blossom midge, ns: nonsignificant        
¹adjusted to 13% moisture, ²adjusted to 12%        

 

Table 6. Effect of application timing and variety        
  HT LOD YLD¹
 PRO² TWT¹ TKW¹ FN OWBM
  in % bu/A % lb/bu g sec no/ spk
Egan
Late Boot 20.4 0.0 23.3 17.8 53.0 23.5 526.4 0.0
50% Heading 21.1 0.0 22.8 18.1 52.8 23.4 535.6 0.0
50% Flowering 20.4 0.0 23.5 18.0 53.1 24.0 537.1 0.0
McNeal
Late Boot 21.8 0.0 23.7 17.0 54.0 25.2 515.9 0.0
50% Heading 42.7 0.0 24.1 17.0 54.4 26.1 517.9 0.1
50% Flowering 21.2 0.0 24.2 16.5 54.7 26.2 515.9 0.1
LSD ns ns ns ns ns ns ns ns
Pr>F 0.4118 1.0000 0.5437 0.3703 0.1814 0.4151 0.6917 0.2130
HT: height, LOD: lodging, YLD: yield, PRO: protein, TWT: test weight, TKW: thousand kernal weight, FN: falling number, OWBM: orange wheat blossom midge, ns: nonsignificant        
¹adjusted to 13% moisture, ²adjusted to 12%        

 

Table 7. Effect of treatment rate and variety        
  HT LOD YLD¹ PRO² TWT¹ TKW¹ FN OWBM
  in % bu/A % lb/bu g sec no/ spk
Egan
Untreated Check 20.7 0.0 24.5 17.5 53.5 24.1 531.4 0.0
Salicylic acid 21 g ai/A 21.0 0.0 23.2 18.1 52.9 23.3 536.4 0.0
Salicylic acid 42 g ai/A 20.3 0.0 21.9 18.3 52.7 23.6 531.4 0.0
McNeal
Untreated Check 42.3 0.0 24.6 16.7 54.5 26.0 518.3 0.0
Salicylic acid 21 g ai/A 21.7 0.0 24.1 16.8 54.4 25.6 515.9 0.1
Salicylic acid 42 g ai/A 21.7 0.0 23.4 17.0 54.3 25.9 515.5 0.1
LSD ns ns ns ns ns ns ns ns
Pr>F 0.4060 1.0000 0.2903 0.4796 0.2222 0.8449 0.8413 0.5795
HT: height, LOD: lodging, YLD: yield, PRO: protein, TWT: test weight, TKW: thousand kernal weight, FN: falling number, OWBM: orange wheat blossom midge, ns: nonsignificant        
¹adjusted to 13% moisture, ²adjusted to 12%        

 

 

Table 8. Effect of application timing, treatment rate and variety                
  Height (in)  Lodging (%)  Yield¹ (bu/A)  Protein² (%)  TWT¹ (lb/bu)  TKW¹ (g)  FN (sec)  OWBM (no/spk) 
  Egan McNeal Egan McNeal Egan McNeal Egan McNeal Egan McNeal Egan McNeal Egan McNeal Egan McNeal
Check
Late Boot 20.7 21.7 0.0 0.0 25.7 24.9 16.9 17.1 53.7 53.8 24.3 25.4 524.1 522.3 0.1 0.0
50% Heading 21.0 84.7 0.0 0.0 23.8 25.3 17.8 16.5 53.3 54.8 23.9 26.7 534.6 511.6 0.0 0.1
50% Flowering 20.3 20.7 0.0 0.0 23.9 23.7 17.7 16.5 53.3 54.8 24.0 26.0 535.5 521.0 0.0 0.0
Salicylic acid 21 g ai/A
Late Boot 20.7 22.0 0.0 0.0 23.3 23.3 17.8 16.7 53.0 54.2 23.4 25.2 536.6 499.2 0.0 0.0
50% Heading 21.3 21.7 0.0 0.0 23.5 24.5 18.1 17.1 52.6 54.2 22.7 25.8 531.5 529.8 0.1 0.1
50% Flowering 21.0 21.3 0.0 0.0 22.9 24.4 18.4 16.6 52.9 54.7 23.7 25.8 541.0 518.7 0.0 0.1
Salicylic acid 42 g ai/A
Late Boot 20.0 21.7 0.0 0.0 20.9 23.1 18.6 17.2 52.2 54.0 22.9 25.0 518.5 526.2 0.0 0.0
50% Heading 21.0 21.7 0.0 0.0 21.2 22.5 18.5 17.3 52.6 54.1 23.7 25.9 540.7 512.3 0.0 0.0
50% Flowering 20.0 21.7 0.0 0.0 23.8 24.4 17.9 16.5 53.2 54.7 24.4 26.8 534.9 508.1 0.0 0.2
LSD ns  ns  ns  ns  ns  ns  ns  ns 
Pr>F 0.4324  1.0000  0.3365  0.5002  0.3449  0.8856  0.2147  0.6929 
TWT: test weight, TKW: thousand kernal weight, FN: falling number, OWBM: orange wheat blossom midge, ns: nonsignificant                
¹adjusted to 13% moisture, ²adjusted to 12%