Oakes Irrigation Research Site
Carrington Research Extension Center * North Dakota State University
P.O. Box 531, Oakes, ND 58474-0531, Voice: (701) 742-2189, FAX: (701) 742-2700, E-mail: Leonard.Besemann@ndsu.edu

PUMPKIN WEED CONTROL STUDY

Richard Greenland


Results summary

Table 63. Herbicide treatments in the pumpkin weed control study

Table 64. Control of redroot pigweed, lambsquarters, hairy nightshade, foxtail, and purslane

Table 65. Pumpkin Injury, stand, number and yield, fruit size, and overall pumpkin quality score

        Weed control is difficult in pumpkins because few herbicides are available for pumpkin production. A new herbicide, Sandea, recently came on the market for use in pumpkins. We tested this herbicide and looked at several other herbicides and herbicide combinations for use in pumpkins.


MATERIALS AND METHODS


Soil:

Maddock sandy loam and Embden sandy loam; pH=6.9; 2.3% organic matter; soil-Pand soil-K was very high; soil-S was low.

Previous crops:

2004 - field corn; 2003 - sweet corn; 2002 - carrot.

Seedbed

preparation:

Chisel plow on April 14. Disked on May 6. Multiweeded (field cultivated) on May 27 to smooth the seedbed and to incorporate fertilizer.

Planting:

‘New Rocket’ pumpkin seeds were planted 1 ft apart in rows 8 ft apart on May 27. On July 8 thinned to an in-row spacing of one plant every 3 ft.

Plots:

Plots were 17 ft long by 8 ft (one row) wide. The study had 4 reps.

Fertilizer:

On April 15 broadcast 26 lbs N/acre and 30 lbs S/acre as 21-0-0-24. Fertigate 40 lbs N/acre on June 18 and 50 lbs N/acre on July 7 as 28-0-0.

Irrigation:

Overhead sprinkler irrigation as needed.

Pest

control:

Weed control treatments are given in Table 63. Sprayed Ambush (8 oz/acre on July 5) and Asana ( 8 oz/acre on July 27) to control cucumber beetle.

Harvest:

Hand harvested on September 27 to September 28.


RESULTS


           Authority injured pumpkins the most, but Sandea, Outlook and Raptor also injured pumpkins. The injury disappeared later in the season. Authority gave good to excellent control of all weeds except foxtail and purslane. Outlook and Raptor gave fair to good control of all weeds. Sandea gave excellent pigweed control, but poor nightshade, foxtail, and purslane control. It controlled lambsquarters when applied PRE but not when applied POST. Yields were lower with Sandea treatments due to weed competition. Best weed control across all weeds was Outlook plus any one of the other herbicides. Highest yields were with the hand weeded check and with Outlook plus any one of the other herbicides. Authority, Outlook and Raptor are currently not labeled for pumpkin production.


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Table 63. Herbicide treatments in the Oakes Irrigation Research Site 2005 pumpkin weed control study.

Treatment

number

Herbicide(s)

Rate per acre

Application timing1

1

Authority

3 oz

PRE

2

Outlook

1 pt

PRE

3

Raptor

5 oz

PRE

4

Authority + Raptor

2 oz + 4 oz

PRE

5

Outlook + Raptor

1 pt + 4 oz

PRE

6

Outlook + Authority

1 pt + 2 oz

PRE

7

Sandea

1/2 oz

PRE

8

Outlook + Sandea

1 pt + 1/2 oz

PRE

9

Sandea + NIS

1/2 oz

POST

10

Outlook + Sandea + NIS

1 pt + 1/2 oz

PRE + POST

11

Handweeded check

 

12

Unweeded check

 
1PRE treatments were applied on May 27. POST treatment was applied on June 24 with pumpkins 6 inches tall
  and 12 inches across. Weeds were 1 to 5 inches tall.
All Treatments were applied with a CO2 backpack sprayer using AI 110-04 flat fan nozzles, 23 gpa, at 52 psi.

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Table 64. Control of redroot pigweed, lambsquarters, hairy nightshade, foxtail, and purslane by herbicides in
the Oakes Irrigation Research Site 2005 pumpkin weed control study.

Treatment1

Redroot Pigweed

Lambsquarters

Hairy nightshade

Foxtail

Purslane

Jun 22

Jul 27

Jun 22

Jul 27

Jun 22

Jul 27

Jun 22

Jul 27

Jun 22

Jul 27

 

--------------------------------------------------------- 0 to 102 -----------------------------------------------------------

1

10.0 a3

10.0 a

10.0 a

10.0 a

10.0 a

10.0 a

9.3 ab

4.8 cde

10.0 a

7.8 bd

2

10.0 a

8.8 b

8.8 bc

7.8 bc

9.8 a

8.8 abc

10.0 a

9.0 a

9.8 a

8.5 ac

3

9.5 a

7.7 c

9.5 abc

8.3 b

8.8 b

8.3 abc

8.3 b

6.3 bc

8.0 b

6.0 ef

4

10.0 a

10.0 a

10.0 a

10.0 a

10.0 a

9.5 ab

8.3 b

5.0 cd

9.5 a

7.5 ce

5

10.0 a

7.8 c

10.0 a

8.3 b

10.0 a

9.3 ab

9.8 a

8.5 ab

10.0 a

7.6 be

6

10.0 a

10.0 a

10.0 a

10.0 a

10.0 a

10.0 a

9.8 a

8.5 ab

10.0 a

8.0 bc

7

10.0 a

10.0 a

10.0 a

10.0 a

6.8 d

4.3 f

8.5 b

5.5 cd

9.8 a

9.5 ab

8

10.0 a

10.0 a

9.8 ab

9.8 a

9.8 a

7.5 d

10.0 a

8.3 ab

9.8 a

9.3 ab

9

8.0 b

10.0 a

7.3 e

7.0 c

7.3 cd

6.0 e

7.0 c

2.8 e

5.5 c

5.5 f

10

10.0 a

10.0 a

8.5 cd

7.3 c

10.0 a

8.8 abc

10.0 a

9.8 a

10.0 a

8.3 ac

11

7.3 c

10.0 a

6.8 e

10.0 a

7.8 c

10.0 a

7.0 c

10.0 a

5.0 c

10.0 a

12

7.3 c

8.0 bc

7.5 de

6.0 d

7.5 c

  7.8 cd

7.0 c

3.8 de

5.8 c

  6.3 df

 

Probability

<.0001

0.0001

<.0001

<.0001

<.0001

<.0001

<.0001

<.0001

<.0001

<.0001

C.V. (%)

2

3

4

4

3

6

8

22

8

14

1See Table 63 for list of treatments.

2Ratings from 0 to 10 with 0 = weed completely covers plot; 10 = no weeds in plot.

3Values in the same column followed by the same letter are not significantly different at the 0.05 level.


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Table 65. Pumpkin Injury, stand, number and yield of pumpkins, fruit size, and overall pumpkin quality score in the
 Oakes Irrigation Research Site 2005 pumpkin weed control study.

Treatment1

Pumpkin (Jun 22)

Number of pumpkins

Pumpkin yield

Fruit

Overall

injury

stand

marketable

total

marketable

total

size

score

 

%

--------------- 1000s/acre -----------------

--------- tons/acre --------

lbs/fruit

1 to 10

 

1

55 e2

3.6

2.6

3.0 ac

15.0

16.7 bc

11.8

8.0 a

2

15 c

4.6

2.1

3.0 ac

13.7

17.9 ac

13.0

7.6 abc

3

18 c

3.6

2.0

2.6 bd

12.6

14.0 cd

12.1

7.8 abc

4

40 de

4.5

2.4

2.8 ad

16.1

17.2 bc

13.2

7.6 abc

5

28 cd

3.9

2.7

3.8 a

17.8

21.7 ab

12.8

7.3 cd

6

28 cd

4.0

2.6

3.4 ab

17.0

21.0 ab

13.3

7.5 abc

7

23 c

3.8

2.0

2.6 bd

10.8

12.7 cd

11.0

7.4 bcd

8

23 c

2.2

2.0

2.6 bd

13.3

15.4 cd

14.7

7.9 ab

9

  3 ab

2.5

1.6

1.9 d

8.7

10.0 d

10.9

7.4 bcd

10

  5 b

4.4

2.0

3.2 ab

13.2

21.5 ab

13.6

7.3 cd

11

  0 a

3.0

2.7

3.8 a

18.6

23.7 a

13.4

6.9 d

12

  3 ab

4.5

1.8

2.1 cd

12.3

14.1 cd

12.5

7.3 cd

 

Probability

<.0001

0.33

0.43

0.008

0.099

0.0009

0.09

0.04

C. V. (%)

26

38

31

23

29

22

12

6

1See Table 63 for list of treatments.

2Values in the same column followed by the same letter are not significantly different at the 0.05 level.


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