Keith Jarvi

 

Background information pertaining to Warrior insecticide experiments conducted near Center in Knox Co. NE, 2004.

 

Species

 

                Two-striped grasshopper:  Melanoplus bivittatus (Say)

                Red-legged grasshopper:  Melanoplus femerrubrum (DeGeer)

                Migratory grasshopper:  Melanoplus sanguinipes (Fabricius)

 

Objective

To compare the efficacy of various rates of Warrior vs a standard Sevin XLR on grasshoppers in a pasture situation.

 

Agronomic

Pasture:  Mixed grass – alfalfa

Application Equipment:      Backpack sprayer with 5 ft boom

                                                                All liquids applied at 15. 25 gpa at 24 psi

                Plot Direction:       Northwest-Southeast

Plot dimensions:   30 X 10 ft

Applied 28 June

Wind N 0-5 mph

Temperature 65 degrees F

 

Treatments

 

                Warrior 1.92 ox acre (16.8 grams ai/hectare)

                Warrior 2.56 oz/acre (22.4 grams ai/hectare)

                Warrior 3.20 oz/acre (28.0 grams ai/hectare)

                Warrior 3.84 oz/acre (33.6 grams ai/hectare)

                Sevin XLR 16 oz/acre

                Untreated (plots sprayed with water only)

 

Experimental Design and Evaluation

 

                Randomized complete block with 4 replications

                Ratings:  Number of grasshoppers per 10 sweeps of a 15 inch diameter net

               

                Discussion:  This plot was surrounded by pasture with 20 or more hoppers per square yard.  Most hoppers were in the 2nd instar when this plot was treated.  Notice there were more hoppers in the treated plots after 14 days.  This was probably due to removal of predators (i.e. ground spiders) from the plot.  Initial control by the 3 higher rates of Warrior was very good and the residual was better at the 8 day post as rates went higher, but residual effects were removed sometime between the 8-14 day post period (lower rate of Warrior and Sevin between 3 and 8 days). 

 

 

 

 

 

 

 

 

 

 

Table 1.  Warrior Rate Experiment, Knox Co. NE 2004

                Number of grasshoppers per 10 sweeps

 

 

 

1-Jul

 

 

 

 

 

 

 

Rate

 

Rep 1

 

Rep 2

 

Rep 3

 

Rep 4

Average

% control

Warrior

 

1.92

 

31

 

16

 

25

 

13

 21.25 a

71.38

Warrior

 

2.56

 

2

 

18

 

8

 

11

 9.75 a

86.87

Warrior

 

3.2

 

9

 

7

 

3

 

12

 7.75 a

89.56

Warrior

 

3.84

 

5

 

4

 

7

 

10

 6.5 a

91.25

Sevin XLR

 

16

 

19

 

40

 

46

 

56

 40.25 b

45.79

Untreated

 

 

 

50

 

66

 

95

 

86

 74.25  c

0.00

 

 

 

 

 

 

 

 

 

 

6-Jul

 

 

 

 

 

 

 

Rate

 

Rep 1

 

Rep 2

 

Rep 3

 

Rep 4

 
Average

% control

Warrior

 

1.92

 

138

 

74

 

93

 

69

 

 93.5 bc

-1.63

Warrior

 

2.56

 

31

 

74

 

56

 

59

 

 55 ab

40.22

Warrior

 

3.2

 

39

 

59

 

27

 

62

 

 46.75 a

49.18

Warrior

 

3.84

 

34

 

21

 

49

 

41

 

 36.25 a