by Madisyn 7 th Grade Science Project March 24, 2011

My Question is “ Can an entomopathogenic Fungus Control Insect Pests?”

My hypothesis Is “I think the fungus will control insect pests.”

Constants  Same temperature  Same seeds planted  Same insects  Same fungus  Same amount of water  Same light regime  Same soil

Independent Variable The independent variable in my experiment is the treatment with the fungus, Beauveria bassiana.

Dependent Variable The dependent variable in my experiment is the insects, Heliothis virescens cotton bollworm.

 120 Heliothis virescens (larvae or worms)  Beauveria bassiana (fungus in liquid solution)  1750 soybean seeds  2 pair forceps  7 pans  1 bag Vermiculite  1 camera  21 cups water  1 pencil  1 notebook  1 pair gloves

1. Gather the materials. 2. Lay down the vermiculite in the pan. 3. Planted the soybeans. 4. Put another layer of vermiculite over the soybeans. 5. Watered the seeds with three cups of water. 6. Made a greenhouse using a tarp to cover the light and heat source.

7. Watered plants every other day using one and a half cups of water. 8. Allow plants to grow to a height of six inches before introducing the treatment. 9. Allowed larvae to grow to the third instar or stage. 10. Open rearing cups to expose the larvae. 11. Used a dropper to squirt the liquid fungus solution on the larvae.

12. Placed the treated larvae on the three pans of plants. Three replications of treated larvae. 13. Using a different pair of forceps I removed 60 untreated larvae from rearing cups and placed the insects on the plants. Three replications of the untreated larvae. 14. I moved treated plants to a room with a light source and heat, then I took the untreated plants to a different room with a light source and heat.

15. I continued to water plants every other day. 16. I observed plants daily to see if the insects had eaten the plants. 17. I also observed to see if the insects had been affected by the treatment or if they were feeding normally. 18. I recorded observations such as how many had died from the fungus.

19. I recorded how many plants were eaten. 20. I took pictures of all the stages of the insects as they continued to grow untreated. 21. Took pictures of plants as they were being eaten. 22. I removed dead treated larvae from plants and placed them in the rearing cups. The fungus continued to grow on the dead larvae.

23. I recorded data from the experiment for twelve days. 24. I recorded how many plants were eaten. 25. I put the untreated larvae back in the cups after they had eaten all the plants so they could pupate and develop into adults. 26. The experiment was held at 72 degrees F. 27. The light/dark regime was 16 hours light and 8 hours dark.

Rep1Rep2Rep3Rep1Rep2Rep3Control PLT eaten Lar died PLT eaten Lar died PLT eaten Lar died PLT eaten Lar died PLT eaten Lar died PLT eaten Lar died PLT eaten Lar died trt untrt d d d d d d d d d d d d

Treated Untrt Control Avg-plt eaten Avg-Lar died Avg-plt eaten Avg-Lar died Avg-plt eaten Avg-Lar died day day day day day day day day day day day day

The insects treated with Beauveria bassiana all died after six days while the untreated insects stayed alive throughout the entire experiment. Plants fed on by untreated larvae all died while the plants fed on by treated larvae had a little damage but they still lived and thrived throughout the experiment.

My question is “ Can a fungus control insect pests?” My hypothesis is I think a fungus can control insect pests. I thought this would be my answer because a fungus that naturally occurs in the soil already works on insects, so if you did this in an experiment it would work just the same with any kind of insect or plant. I accept my hypothesis because the fungus did kill the insects that were treated with it and therefore allowed the plants to grow uninterrupted.

Beauveria bassiana is a naturally occurring fungus in soils throughout the world. Beauveria is a fungus which causes a disease known as the white muscadine disease in insects. When spores of this fungus come in contact with the skin of leaf feeding insects, they grow inside the insect and eventually kill it. Beauveria covers the insect body with a layer of white mold, hence the name white muscadine disease. general/htms/bassiana.htm

Heliothis virescens is an insect pest of soybeans, cotton, tobacco, and numerous vegetables and occurs mostly in the Southern U.S. and the Caribbean. It feeds on the leaves of plants and can destroy entire crops if not kept under control. Heliothis feeds constantly in the larval or worm stage on leaves of cotton, tobacco, and vegetables which makes it a good insect to be controlled with Beauveria. creatures/field/tobacco_budworm.htm

I believe that my results were accurate. I believe this because I wrote down what happened to my plants everyday. I would write down how many of the treated insects had died that day, how many leaves the treated and untreated insects ate that day. I also recorded the height of the plants when they were still growing, that was before I put the insects on the plants. I would take pictures of all the plants with and without the insects. I made sure that they all had the right amount of water and light.

If I were to repeat this experiment I would take this fungus which is a biological pesticide and compare it to a chemical pesticide. This chemical pesticide would probably kill the insects, but would also do harm to the environment as well as humans. So therefore I would want to see if the fungus kills the insects as well as the chemical might. I would like to be able to recommend to farmers the biological pesticide rather than the chemical pesticide which is harmful to the environment.

In summary, I can conclude that a biological pesticide ( Beauveria bassiana) can control insect pests. My data can prove that my hypothesis is correct. When the insects ( Heliothis virescens, the cotton bollworm ) in my experiment were treated with this entomopathogenic fungus they ate the plants for a few days, but were killed after six days and the plants could recover from the feeding and grow well. The cotton bollworms that were not treated continued to feed and at the end of 12 days killed all the plants, none of the insects died.