IntroductionAbstract

In this experiment Tagetes Minuta and Lippia Javanica will be grown and then the leaves will be harvested, dried, and crushed into a fine powder. Solutions of 50 grams dried leaves, 5 grams liquid soap, and 500 milliliters of water (one solution of lippia the other of tagetes leaves) will be prepared. Then pea aphids, six per testing will be directly exposed to the solutions by a micropipette in a Petri dish (containing a pea leaf to factor out starvation) and the aphids will be observed, using a dissection scope. The amount of deaths of aphids in the experiment will be recorded and then results will be tabulated by a one-way T-test followed by a scheffe post-hoc test.

Need

The need for this experiment is that Aphids are common pests all over the world and

transmit various plant diseases, as well as destroy crops by feeding off the stems and

leaves of the plants. Aphids can mutate insecticide resistances to synthetic chemicals (such as kdr and ace-1R

resistance) and so it is imperative that a natural insecticide can be found.

The above image is a simulated habitat for aphids or “bug rearing cage”. Inside it contains pea plants that are watered twice weekly. The top of the cage is covered with a fine mesh to prevent aphid escape and to still let air in. The cage can hold a couple thousand aphids at a time. (taken by author)

Experimental solution

Humidifier/Vaporizer

Tagetes Minuta

The above image shows the Tagetes Minuta plants being grown in a hot humid environment with lots of sunlamps to recreate their habitat. The blue bottle contains the already made Lippia solution (taken by author)

Literature Review

•Katsvanga and Chigwaza (2004) study how lippia javanica and tagetes minuta reduce aphid population on Brassica Capitata (cabbage)

•The term "knockdown resistance" is used to describe cases of resistance to diphenylethane (e.g. DDT) and pyrethroid insecticides in insects and other arthropods that result from reduced sensitivity of the nervous system (soderlund, 2003)

Purpose

The purpose of this experiment is to see how Lippia Javnica and Tagetes Minuta solutions will affect aphid mortality/population reduction when applied directly to aphids on pea leaves

HypothesisNull: Direct exposure to the Tagetes and Lippia solutions will not affect the mortality rate of the aphids

Alternate: Direct exposure to the Tagetes and Lippia solutions will kill the aphids

Aphids on a leafSource: http://www.na.fs.fed.us/spfo/pubs/howtos/ht_walnut/aphids.jpg

Aphids colonizing on pea plant (taken by author)

Dissection scope used to observe aphds in petri dishes during

experimentation and exposure phases (taken by author)