|Using Lippia Javanica and Tagetes Minuta as Natural Insecticides against Aphids
Manhasset Science Research, Manhasset, NY 11030
Aphids are responsible for the 20% yield loss of soy in Nebraska yearly. Lippia and Tagetes were tested as natural insecticides against pea aphids. The purpose of this experiment is to see which of the two experimental insecticides will be more effective at reducing aphid population. The solutions consisted of 50 grams dried leaves, 5 grams liquid soap, and 1000 milliliters of water. Pea Aphids were exposed to the two sprays and the control (distilled water). The aphid groups were observed in Petri dishes under a dissection scope. The amount of time it took the sprays to reach the LD50 mark (how fast it takes for the spray to kill half the tested aphids) was recorded. The results for Lippia were 43 seconds ± 4.3 and the results for Tagetes were 10.3 seconds ± 1.4. The data was analyzed by an Independent Samples T-test (P<.001), which showed a significant difference between the Tagetes and Lippia groups. The safety of the solutions for use on plants was also tested. Three groups: Lippia, Tagetes, and control (distilled water) with the same concentration as used in the aphid testing, were setup, and pea plants in each group were sprayed daily with their assigned spray. Plant heights in centimeters, over 20 weekdays were observed (as a sign of health). The Mean±SD for plant height were Control 14.1±4.1, Tagetes 14.1±4.1, and Lippia 14.1±4.1. The experimental group heights were compared against the control’s height in a One-way ANOVA (P<.05), which showed no significant difference between any of the groups. From the results gathered, the Tagetes spray is more potent and reduces aphid population quicker than the Lippia spray, and both of the solutions are safe to use on plants.