|
Janet J. Knodel, Area Extension Specialist-Crop Protection
Lorilie Atkinson, Research Specialist
SUNFLOWER:
Helianthus annuus
L.
Insecticide Efficacy against Grasshopper
Nymphs on Sunflower TRIAL B, 2003
Twostriped
grasshopper:
Melanoplus
bivittatus (Say)
Migratory
grasshopper:
Melanoplus
sanguinipes (Fabricius)
Registered and experimental insecticides were evaluated for their efficacy at
controlling nymph stage grasshoppers and protecting sunflower seedlings. A
field in north central North Dakota near Westhope, ND had pretreatment counts
of 10 nymph (2-4 instars) grasshoppers/yd2
with the majority being twostriped grasshoppers. Plots were 10 ft wide by 30
ft long. A RCB experimental design with four replicates was used. Insecticides
were applied at V2-3 stage on 13 June using a handheld CO2 boom sprayer at 40 PSI, and 10 GPA and fitted with XR 8001 nozzles. Ten seedlings were assessed
per plot for the percent defoliation at 4, 7, and 14 DAT. Variables were
subjected to ANOVA and means compared using Fisher’s PLSD at the 5%
significance level.
At 4, 7, and 14
DAT, all of the insecticide treatments had significantly lower percent
defoliation than the untreated check. There were no significant differences
between the different insecticide treatments indicating that all treatments
controlled grasshoppers. At 14 DAT, the defoliation increased slightly as
grasshoppers continued to move into plots to feed and as insecticide residue
was diminished.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Decis 1.5 EC |
0.012 lb ai/acre |
0.6b |
0.4b |
5.7b |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Mustang Max 0.8 EC |
4 fl oz/acre |
0.8b |
0.7b |
5.0b |
|
Proaxis 0.49 CS |
3.84 fl oz/acre |
0.2b |
1.1b |
5.7b |
|
Warrior T 1 EC |
3.84 fl oz/acre |
0.7b |
0.6b |
5.2b |
|
Warrior T 1 EC |
2.56 fl oz/acre |
0.5b |
1.3b |
5.3b |
|
Asana XL 0.66 EC |
2.9 fl oz/acre |
0.5b |
0.7b |
5.5b |
|
Asana XL 0.66 EC |
5.9 fl oz/acre |
0.4b |
0.7b |
5.3b |
|
Means within a column followed by the same letter are
not significantly different (ANOVA, Fisher’s PLSD, P<0.05). a Data were
transformed using square root for analysis. The non-transformed data is
presented. |
Part II. Materials Tested for Arthropod
Management
Insecticide Efficacy against Grasshopper
Nymphs on Sunflower TRIAL B, 2003
|
