"The Effect of Pesticides or Herbicides on Lumbricus terrestris"

 

          The purpose of this project is to determine if the pesticides or herbicides Roundup, Ortho Bug-B-Gon, and Ortho Malathion 50 Plus will cause the most mass loss on Lumbricus terrestris.  It is hypothesized that Ortho Malathion 50 Plus will cause more of a mass loss than Ortho Bug-B-Gon or Roundup because of its known toxicity to other living organisms.  Lumbricus terrestris were placed in 12 different containers sectioned into four quadrants.  In test one, each quadrant of the container was sprayed with one application of its designated pesticide and or herbicide.  This was repeated for four days.  The mass was measured in grams, for each worm, everyday for four days.  The results showed that there was not a significant mass loss until application 6.  The greater the concentration the greater mass loss.  It is further noted that death loss occurred in days 2 to 4 in all three applications of pesticides and/or herbicides. Furthermore, when comparing the effects of the three pesticides and/or herbicides, Roundup caused the greatest mass loss. A future study includes determining whether the pesticides and/or herbicides would effectively kill the weeds and bugs, but at the same time not  negatively effect the  Lumbricus terrestris.

 

 

          The most familiar of oligochaetes are earthworms, which burrow in moist, rich soil, emerging at night to explore their surroundings.  In damp, rainy weather they stay near the surface, often with mouth or anus protruding from the burrow several feet underground, coil up in a slime chamber, and become dormant.  Lumbricus terrestris, the form commonly studied in school laboratories, is 12 to 30 cm long.  Giant tropical earthworms may have from 150 to 250 or more segments and may grow to as much as 4 m in length.  They usually live in branched and interconnected tunnels (1).

            Earthworms perform several functions in the garden soil.  Their tunneling activity helps aerate the soil.  The channels they make as they move through the soil allow rain to enter the soil more rapidly, reducing runoff and the potential for erosion.  This also helps improve soil structure by creating a loose soil that is easily penetrated by roots.  Worms increase the nutrients available in the soil for plants.  As worms digest plant material, their castings or excrement concentrate nutrients.  Castings are several times higher in nitrogen, phosphorus, potassium, and magnesium than topsoil.  This nutrient rich material is mixed into the soil where plant roots can use the nutrients.  Also, by incorporating litter into the soil, worms reduce the number of fungus spores on the soil surface and that can help prevent plant diseases such as apple scab (2).

            Earthworms are hermaphroditic; that is, each one produces both sperm and egg cells.  When mating occurs, each receives sperm from the other, then goes its separate way to complete the reproductive process.  Later, the clitellum produces a mucous band that slips forward over the earthworm’s body.  Eggs and sperm are released into this band as it passes over the reproductive pores.  As the band slips off the worm, each end closes to form an oval cocoon.  The cocoon remains in the soil for two or three weeks before the eggs hatch.  About three months later, the young worms will be fully-grown (3).

            Earthworms are prolific, and in good soil conditions they can reach high population levels.  Charles Darwin estimated that a single acre might contain as many as 50,000.  In general, the better the soil the higher the earthworm population.  The high population is kept down by predators such as birds, garter snakes, salamanders, toads, and a number of mammals.  And even though earthworms do not occur naturally in water, they sometimes become the prey to fish when offered on a hook (3).

            Overall, many pesticides and herbicides are toxic to earthworms, yet many of the herbicides are relatively harmless (when used at the prescribed rates).  Limiting the use of the more harmful insecticides, fungicides and fumigants would undoubtedly be beneficial to earthworms (4). 

            Roundup̉ enters plants through foliage and moves systemically to the roots, killing weeds by stopping the production of the substance found only in plants.  Any product not absorbed by plants breaks down into natural materials without moving in or on the soil to untreated plants.  Weeds yellow and wilt within hours with complete kill in 1 to 2 weeks. The active ingredient in this product is glyphosate isopropyamine. Ortho Bug-B-Gon is known to control a wide range of common garden pests including aphids, beetles, caterpillars, mealybugs, mites, and whiteflies on roses, flowers, shrubs, vegetables, small fruit trees and berries.  It also can be used to control exposed nuisance pests, including ants, cockroaches, earwigs, fleas, and spiders found outdoors around the home.  It is harmful if inhaled or absorbed through the skin.  Its active ingredient is Diazinon (6).  Orthỏ Malathion 50 Plus works very similar to the Bug-B-Gon in controlling pests, but is also very toxic to fish, aquatic invertebrates, and aquatic life stages of amphibians, so it should not be applied directly to water.  Drift and runoff may be hazardous to aquatic organisms in areas near  the application site.  Care should be given so as not to contaminate water when disposing of equipment washwaters.  This product is highly toxic to bees exposed to direct treatment on blooming crops or weeds so this product should not be applied to blooming crops or weeds if bees are visiting the treatment area.  Malathion, the active ingredient, is known to cause aspiration problems(7). 

            The purpose of this project is to determine which pesticide or herbicide Orthỏ Malathion 50 Plus, Ortho Bug-B-Gon̉ or Roundup̉, will cause the most mass loss on Lumbricus terrestris.  It is hypothesized that Orthỏ Malathion 50 Plus will cause more of a mass loss effect on the Lumbricus terrestris than Ortho Bug-B-Gon or Roundup because of its known toxicity to other living organisms.


 

Materials

 

Small Latex Gloves                                                         Safety Goggles

Apron                                                                                      Lumbricus terrestris

12 Rubbermaid containers                                               12 wood dividers

Spring Water                                                                   Plastic Spoon

2 Plastic Spray bottles                                                     Bowl

1 can of ground coffee                                                    1 box of oatmeal

3 cloth towels                                                                  Fume Hood

1 bag of potting soil                                                        Orthỏ Bug-B-Gon

Orthỏ Malathion 50 Plus                                               Roundup̉

Electronic Balance

 

 

Procedures

 

For application 1:

 

1)      Insert wooden dividers into each tub to separate each worm.

2)      Secure any opening in the tub with masking tape.

3)      Measure out 1 cup of potting soil for each quad section.

4)      Make and apply 8 tags labeled control, Roundup̉, Otho Bug-B-Gon̉ and Ortho Malathion 50 Plus̉.

5)      Separate out 36 worms.

6)       Pour spring water into bowl to wash each worm and lay out paper towels for drying.

7)      Pour 60mL of spring water and 1tsp of oatmeal into each quad.

8)      Separate the worms into groups of 4 for each tub, measure mass and record, place into designated areas.

9)      Turn the Fume Hood on, wearing gloves, goggles, and an apron, spray each quad once (1.0 ml) with the correct pesticide or herbicide matching the label on the tub (except for control samples).  Cover the top of tubs with cloth towel to retain moisture.

10)    Every 24-hours wash, dry, take mass, and apply pesticide or herbicide to all samples except the control.  Also give all samples 6.0 ml of spring water and 3.0 ml of oatmeal.  Cover each tub.

For application 2, 4, and 6, follow these steps:

11)    Use 12 tubs and 12 dividers instead of 8.

12)    Use previous step 2.

13)    Separate 48 worms and wash in spring water.

14)    Make out 12 tags labeled control 1, control 2, control 3, Roundup̉ 2, Roundup̉ 4, Roundup̉ 6, Ortho Bug-B-Gon̉ 2, Ortho Bug-B-Gon̉ 4, Ortho Bug-B-Gon̉ 6, Ortho Malathion 50 Plus̉ 2, Malathion 50 Plus̉ 4, Malathion 50 Plus̉ 6.

15)    Use previous steps 6-8.

16) Turn Fume Hood on, wear gloves, goggles, and an apron, this time apply tubs labled 2 with 2.0 ml, 4 with 4.0 ml, and 6 with 6.0 ml.   Cover the top of tubs with cloth towels.

NOTE:

¨  The same amount of food and water were given to all worms, nothing else was added to the controls.

 

 

 

 

 

Table 1

Average Mass of Lumbricus terrestris under one Application of Different Pesticides or Herbicides (g)

 

Starting Mass

Day 1

Day 2

Day 3

Day 4
Control

4.8

4.3

4.1

3.8

3.7

Roundup̉

4.9

4.1

3.9

3.8

3.1

Ortho Bug-B-Gon̉

5.4

4.6

4.4

4.3

4.2

Ortho Malathion 50 Plus̉

4.9

4.4

4.0

3.5

3.4

 

 

 

 

 

Table 2

Average Mass of Lumbricus terrestris under two Application of Different Pesticides or Herbicides (g)

 

Starting Mass

Day 1

Day 2

Day 3

Day 4

Control

4.9

4.7

6.5

6.7

6.2

Roundup̉

4.4

3.3

4.8

4.0

5.2

Ortho Bug-B-Gon̉

4.9

4.1

5.2

5.0

5.4

Ortho Malathion 50 Plus̉

4.3

3.5

3.5

4.0

3.5

 

 

 

 

 

Table 3

Average Mass of Lumbricus terrestris under four Application of Different Pesticides or Herbicides (g)

 

Starting Mass

Day 1

Day 2

Day 3

Day 4

Control

4.4

5.1

6.9

7.4

6.5

Roundup̉

4.3

1.9

2.5

2.9

3.0

Ortho Bug-B-Gon̉

4.4

3.5

2.9

3.5

4.4

Ortho Malathion 50 Plus̉

4.4

3.8

5.8

5.7

5.7

 

 

 

 

 

 

Table 4

Average Mass of Lumbricus terrestris under six Application of Different Pesticides or Herbicides (g)

 

Starting Mass

Day 1

Day 2

Day 3

Day 4

Control

4.5

4.4

5.4

6.1

6.3

Roundup̉

4.3

3.2

2.0

1.5

1.4

Ortho Bug-B-Gon̉

4.4

2.7

4.0

4.1

4.0

Ortho Malathion 50 Plus̉

4.8

4.0

5.4

4.2

4.1








Conclusions

The result of this experiment showed that there was not a significant mass difference of the worms from day one to day four with one application of the pesticides and/or herbicides per day.  The control showed a mass loss of 1.1g.  The Roundup̉ samples showed a loss of 1.8g.  The Ortho Bug-B-Gon̉ samples showed a loss of 1.2g, while the  Orthỏ Malathion 50 Plus showed a loss of 1.5g. The control with no applications for application 2 test showed a mass gain of 0.5g. The results with 2 applications per day showed a mass gain of 0.8 g with the Roundup̉ samples. The Ortho Bug-B-Gon̉ samples showed a slight mass gain of 0.5g, while the Orthỏ Malathion 50 Plus samples showed a mass loss of 0.8g.  The results with 4 applications of pesticides per day were as follows; control with a mass gain of 2.1g; Roundup̉ samples with loss of 1.3g; the Ortho Bug-B-Gon̉ samples showed an apparent no loss or gain; the Orthỏ Malathion 50 Plus samples showed a loss of 0.8g.  The results for the test with six applications per day showed a significant mass loss only in the Roundup.  There was a mass gain of 1.8g in the control.  The samples with Roundup̉ showed a significant mass loss of 2.9g, while the  Ortho Bug-B-Gon̉ samples only showed a slight mass loss of 0.4g.  The samples with Orthỏ Malathion 50 Plus showed just a slightly greater loss than the Bug-B-Gon with a loss of 0.7g.

            Overall, the results showed that there was not a significant mass loss until application six.  The greater the concentration, the greater the mass loss.  It is further noted that death loss occurred in day 2 to 4 in all three applicantions of pesticides and/or herbicides.  It was hypothesized that Orthỏ Malathion 50 Plus will cause more of a mass loss on the worms than Ortho Bug-B-Gon̉ or Roundup̉. The results of this experiment indicate that the hypothesis was rejected because Roundup̉ had the greatest mass loss. A possible source of error could be that the Lumbricus terrestris did not receive sufficient water or food, or they received too much light.   A future study includes determining whether the pesticides and/or herbicides would kill the weeds and bugs, but at the same time not negatively effect the Lumbricus terrestris.

 

Works Cited

 

 

1)  Larson, Allan, Cleveland P. Hickman, Jr., and Larry S. Roberts.  Integrated Principles of Zoology.  New York:  McGraw-Hill, 2001.

 

 

2)  “Backyard Conservation: The Wonder of Worms.” [ONLINE] Available http://environment.about.com/library/we…/blbacky1.htm?iam=dpile&terms=earthorm+habita, November 14, 01.

 

3)   Dramer, David C.  “Science and Children.”  March 1986, pp. 33-34.

 

4)  “The Effect of Chemicals on Earthworm Populations.” [ONLINE] Available http://www.crop.cri.nz/psp/articles/docs/worms/wormchem.htm, October 17, 01.

 

5)  “Roundup.”  Monsanto Company, Lawn and Garden Products, 2000.

 

6)  “Ortho Bug-B-Gon.”  The Solaris Group of Monsanto Company, 1995.

 

7)  “Ortho Malathion 50 Plus.”  The Ortho Group, 2001.

 

Acknowledgments

 

The author would like to thank the following persons for the support or materials for the completion of this project:

 

My mom, dad, and brother

Mrs. Benne

Mrs. McCurry

Mrs. Pam Chaney

Mrs. Rogers

Roger and Colby form Rogers State University

Mr. Eubanks

All of my fellow classmates

Welch Public School, for the use of materials and computers