My Sigma Xi Showcase Presentation

1. Neem: A Panacea for Insect
Control
Nirupa Gadi
Junior
Charles M. Russell High School
Great Falls, Montana 59404
Email: nirupagadi@yahoo.com

2. Abstract
 The neem tree (Azadirachta indica), which grows in tropical
areas, has a lot of medicinal and pesticidal properties.
Virtually every part of the tree is beneficial for healing and has
been used for over 2000 years. The extract has been used to
treat a wide variety of infections and provides a nontoxic,
environmentally friendly option to chemical insect repellents.
 In the present study, the neem extracts were evaluated in a
laboratory against the Army Worm (Spodoptera litura) that
damages almost all plants. My studies indicated that neem
extracts can kill the eggs and other life stages (larvae, pupae
and adult) of the Army worm. Since extracts of neem are
ecologically safe, the chemical can be used to control the
insects in gardens and around human dwellings.

3. he neem tree is widely grown in tropical countries Seeds from the Neem Tree

4. Introduction (Neem)
 Neem is a very fast growing evergreen; it is a part of the
mahogany family and is very common in dry, tropical regions.
 Its binomial name is Azadirachta indica.
 Neem is very relied upon in every part of the world, being
used as a pesticide to stomach ulcers to even cosmetic uses
(Schmutterer, 1995).
 The plant is very toxic to insects but not to humans.
 Even body soap and toothpaste are made from neem leaves
and are sold (Saxena, 1989).

5. Introduction (Neem) Cont.
 The leaf of the plant is used for leprosy, eye disorders,
intestinal worms, skin ulcers, cardiovascular disease,
diabetes, fever, gingivitis, and liver problems (Jacobson,
1989).
 The bitter tasting plant repels all insects, naturally and
effectively, without damaging the crop itself (Isman, 1993).
 The entire plant can be used to make treatments
 The worst fear of any farmer is having their crops destroyed
by insects. Chemical insecticide may seem like a viable
option, but they can leave residue on the plant which can be
toxic to humans.
 Many farmers have started to use the plant as an insecticide
(Senthil-Nathan, 2013).

6. Introduction (Army Worm)
 The army worm is also known as the tobacco caterpillar, which
metamorphosizes into a moth.
 Spodoptera litura is one of the most damaging insect pests of
agricultural crops.
 This is a highly generalist defoliator.
 A wide host range of over 120 plant species are known including
many vegetable, fruit, and ornamental crops.

7. Neem: Mode of Action
Growth
Regulator
Adulthood
Impairment
Reproduction
Suppressor
Egg Laying
Reduction
Egg Hatching
Reduction
Larval Fitness
Pesticide
Resistance
Inhibition
Feeding
Inhibitor

8. Hypothesis
 Most “backyard” crops are severally damaged by the
army worm.
 Insecticides that are used are toxic and can not be
sprayed near communities.
 I would like to explore the possibilities on whether crude
extracts of neem can effectively controlled the army
worm.
 I report data from laboratory studies showing the
effectiveness of the neem extracts for insect control. I
have used the army worm as a model insect for my
experiments.
 The research information from my study can be useful
not only to home owners but also commercial growers.

9. Experimental Methods
Neem Leaf Extract:
Fresh neem leaves were
soaked in water at a ratio
of one kg of leaves to five
liters of water for 48 hours.
After that, the leaves were
ground in the water. The
liquid was used for
laboratory experiments.

10. Experimental Methods
 Experiment 1: Twenty eggs of the army worm were
placed in a Petri dish with filter paper, and 2 ml of neem
extract were sprayed directly on the eggs using a hand
sprayer. At the same time, four of the Petri dishes with a
similar set of experiments were done for replication. The
untreated control was maintained for the comparison.
 Experiment 2: Twenty young larvae of the army worm
were placed in each Petri dish with cut leaves of
eggplant and 2 ml of neem extract were sprayed directly
on the larvae. This experiment was repeated five times.
A treatment without the spray served as control.

11. Observations
 After complete hatching of the twenty eggs set out,
counts were made on the unhatched eggs.
 Also, counts were noted on the dead larva, pupa, and
adult survival in the treated and control.
Statistics
 The analyses were conducted using SAS version 9.3
(SAS Institute, 2011).
 The number of unhatched eggs and the different insect
stages that died were analyzed using a paired t-test.

12. Experimental Results
 My findings indicated that the treatment with the neem
extracts affected the eggs, larvae, pupae, and adults more
than the untreated control.
 Also, malformed larvae, pupae, and adults were recorded in
the treatment with the neem extracts.
 In the end, all the insects died in all treatment with the neem
extracts.

13. Normal Eggs Affected Eggs
Results: Eggs
 Eggs do not hatch when sprayed with neem

14. Untreated Treated
Results: Antifeedency
 Bugs stop feeding

15. Healthy Larva Starving Larva
Results: Larvae
 Neem stops larval activity
Dead Larva

16. Results: Pupae
Normal Pupa Dead Pupa
 Neem produces malformed and dead pupae

17. Results: Adults
Normal Moth Dead Moth
 Misshapen and dead adult army worms caused by neem
exposure

18. 0 20 40 60 80 100 120
Treated
Control
Unhatched Eggs
Mean Percent (+SE) of unhatched eggs of the army
worm
B
A
 Different letters on bars indicate significant differences (Paired t-
test)
Graphs (T-Test)

19. B
B
B
A
A
A
0
2
4
6
8
10
12
14
16
18
Larvae Pupae Adult
Meanmortality
Mean Percent Mortality of Different Life Stages of the Army
Worm
Control Treated
 Mortality was based on 20 larvae per treatment and each
treatment was repeated four times. Different letters on bars indicate
statistically significant differences (P=0.05)
Graphs (Bar)

20. Conclusions
Neem extracts are simple to make; home owners and farmers
can easily replace toxic insecticides being used with neem to
control insects in their gardens.
HOW IS NEEM DIFFERENT FROM
INSECTICIDES?
 Do not expect dead bugs immediately- pests die of starvation and
growth failure in days
 Provide slow but sure control of insects
 It is safe and environmentally friendly!

21. References
Schmutterer, H. 1990. Properties and potential of natural pesticides from the
neem tree, Azadirachta indica. Annu. Rev. Entomol. 35: 271– 297.
Isman, M.B. 1993. Growth inhibitory and antifeedant effects of azadirachtin
on six noctuids of regional economic importance. Pestic. Sci. 38: 57–
63.
Saxena, R. C. 1989. Insecticides from neem, pp. 110–135. In J. T. Arnason,
B.J.R. Philogene, and P. Morand [eds.], Insecticides of plant origin.
ACS Symposium Series 387. American Chemical Society, Washington, DC.
Jacobson, M. ed. 1989. Focus on phytochemical pesticides, vol.1. The
neem tree. CRC, Boca Raton, FL.
Senthil-Nathan, S. 2013. Physiological and biochemical effect of neem and
other Meliaceae plants secondary metabolites against Lepidopteran
insects. Front. Physiol. 4:359. doi: 10.3389/fphys.2013.00359.

22. I would like to thank Sigma Xi for giving me an opportunity
to present the results from my science project on the “2015
Sigma Xi Student Research Show Case”.
Ms. Jenelyn Remolena (University of Guam) and Dr. G.V.P.
Reddy (Montana State University) for their guidance and
help with this project.
Acknowledgements