The document summarizes a study analyzing the antifungal activity of silver nanoparticles synthesized by bacteria against Fusarium sp., a fungus that causes guava wilt. The objectives were to isolate Fusarium sp. from infected guava leaves, screen bacteria for silver nanoparticle production, synthesize nanoparticles from a potent bacteria, and test their antifungal activity against Fusarium sp. The results showed that the silver nanoparticles inhibited fungal growth in a concentration-dependent manner, with no growth observed at a concentration of 200 μl of nanoparticles.

2. ANTIFUNGAL ACTIVITY OF BACTERIAL
DERIVER FROM SILVERNANOPARTICLES
AGAINST CAUSING GUVA WILT CAUSING
FUSARIUM SP.
BY
G.ARJUN
II M.Sc. Applied Microbiology
Sacred Heart College (Autonomous)
Tirupattur.

3. INTRODUCTION
Plant disease result in an annual estimate loss of 10 to 15% of the world major crop
with direct economic losses of up to hundred of billion of dollars. Of these disease
70 to 80 % cause by pathogenic fungi. Plant pathogenic fungi have adverse effect
on crop growth and yield. Silver nanoparticles synthesised from bacterial are
applied to agriculture showing good potential result agianst insects, fungi, bacterial,
and viruses. Fusarium species are important plant pathogens causing various diseases
such as crown rot, head blight, and scab on cereal grains (72), and they may
occasionally cause infection in animals (32).

4. AIM
 To analyze the antifungal efficacy of biosynthesized silver
nanoparticles against Gauva wilt causing Fusarium sp.

5. OBJECTIVES
 To isolate Phytopathogenic fungi from Psidium guajava tree
 • To Identify isolated fungi using Morphological and Microscopic observation.
 • To perform Preliminary Screening for Silver nanoparticles by collected bacteria.
 • To synthesize Silver Nanoparticles Extracellularly from the potent bacterium.
 • To characterize the synthesized Silver Nanoparticles.
 • To perform antifungal activity of synthesized Silver Nanoparticles against

6. SAMPLE COLLECTION

7. Morphological and cultural characterization
Isolation of phytopathogenic fungi from
Psidium guajava infected leaf

8. Fusarium sp. culture grown on rose bengal
agar medium
Isolation of Fusarium sp. from Psidium
guajava infected leaf

9. MICROSCOPIC EXAMINATION
Macro-conidia Micro-conidia

10. Biosynthesis of AgNPs using Klebsiella sp.

11. 0µl 50µl
Antifungal effect of AgNPs against
Fusarium sp.
plate a plate b

12. 100µl 150µl
plate c plate d

13. 200µl
No growth was observed on the plate e

14. BUDGET
COMPONENTS PRICE
Nutrient broth 100ml (1.3g) 20 rupees
Silver nitrate 100ml ( 0.035g) 40 rupees
Distilled water 1l 10 rupees
Container 200ml 5 rupees
Total 75 rupees

15. RESULT
 The antifungal effect of AgNPs against Fusarium sp. was then performed in
concentration dependant manner. Compared to the control group (no silver
nanoparticles), the growth of Fusarium sp. was obviously inhibited by the
silver nanoparticles in a concentration-dependent manner. The size of the
colonies decreased with the increasing concentration of silver
nanoparticles. When the concentration of silver nanoparticles was 200 μl,
no growth was observed on the plate but when the concentration was 50 μl,
the silver nanoparticles showed no inhibitory effect on colony growth. This
silvernanoparticles in our study showed positive inhibitory effect against
Fusarium sp.