Plant extracts used in the study were obtained from Datura stramonium, Allium sativum, Azadirachta indica, Eucalyptus globulus and Lantana camera.

Plant materials and preparation of plant extracts
D. stramonium, A. indica, E. globulus and L. camera were collected from the agricultural research farm. Allium sativum was obtained from local vegetable market. Apparently fresh leaf material was collected and washed with distilled water and then surface sterilized with sodium hypochlorite (NaClO) 1 percent solution for 2 mins then rinsed thrice with sterilized distilled water. Surface sterilized plant leaves were air dried in room temperature (35°C) and homogenized to make 1 to 2 mm diameter fine powder using a grinder. Aqueous extracts were prepared by decoction method²⁴. In brief 20g dried fine powder of every plant sample was gently mixed with 80 ml of sterile distilled water and heated for 10 to 15 mins to remove contamination. Subsequently solution was filtrated through double layered muslin cloth, and finally centrifuged at 8,000 rpm for 25 mins. The obtained supernatant from previous step was filtered through Whatman filter paper No. 1 and sterilized in autoclaved. Sterilized solution considered as 100 percent concentration and preserved aseptically in separate sterile beakers at 4°C until experiment completion.

Collection of pure culture of pathogen
The authentic culture of A. solani was borrowed from the Indian Type Culture Collection, New Delhi, with the ITCC No. 3640. The fungus was sub-cultured and maintained on potato dextrose agar medium (PDA) at 4°C. The pathogenicity was checked under in vitro condition by detached leaf assay (Fig.1).

Evaluation of different plants extracts under in vitro condition
To check the efficacy of five plant extracts against test pathogen under the in vitro condition was done with the help of poisoned food technique²⁵. Different concentrations of test extracts, including 5, 10, 15 and 20 percent was added in PDA medium, mixed gently and 20 ml media poured in Petri dishes. PDA medium without plant extract was taken as control. Petri dishes containing different test extracts with PDA were placed at the centre of each plate with 5 mm diameter mycelial disk from 10 days old A. solani culture and plates were incubated at 27°C for one week and radial growth of mycelium was measured at 7 days after inoculation. This experiment was done with three replications for each treatment. To measure diameter of test pathogen colony by using two perpendicular lines in each Petri plates. The percent inhibition of test pathogen was assessed using the formula²⁶.

I = C−T/C × 100

Where,
I= Per cent inhibition of mycelia growth C = Growth of mycelium in control (mm)
T = Growth of mycelium in treatment (mm)

Preparation of conidial suspension
Conidial suspension was prepared by following Stammler et al.²⁷ with slight modification. 10 ml sterilized distilled water was added to every Petri plate and 7-day old spore colonies were scraped with the help of rubber spatula. 10 ml spore suspensions were made from each plate and conidia density was adjusted to 1.8 × 10⁴ spores ml−1 with the help of haemocytometer.

Inhibition of conidial germination of test pathogens
Five plant extracts were used to check the antifungal activity of aqueous extract on conidial germination of A. solani through microscopic slide technique with slight modification²⁸. The plant extracts at four different concentrations (5, 10, 15 and 20%) was added as films on dried clean microscopic slide. 50 μl conidial suspension was spread over these films and sterile distilled water slide served as a control. Every slide was transfer on a glass rod in a Petri dish under moist conditions and incubated for 3 days at 27°C²⁹. Five slides were replicated three times for each concentration. Lactophenol cotton blue (LCB) was added to each slide to arrest conidia germination after incubation. Each slide was observed under a light microscope at ×400 magnification to determine the germination rates of conidia. The experiment was repeated four times, with three replications every time. The percent inhibition of conidial germination for each treatment was assessed by the given formula:

Percent inhibition = C − T/C × 100

Where,
C = Germinated conidia in control
T = Germinated conidia in treatment

Mycelial deformation study by Scanning electron microscopy (SEM)
Mycelial disks treated with the plant extracts (Datura stramonium, Allium sativum, Azadirachta indica, Eucalyptus globulus and Lantana camera), among them A. sativum (20 %) and mycelial growth of A. solani was prepared by following procedure described by 30 with slight modifications. Mycelial disks were fixed with Karnovsky solution containing 2.5 percent glutaraldehyde, 2 percent paraformaldehyde in a 0.05 M sodium cacodylate buffer (pH 7.2) for two days for SEM study. The mycelial disk gently washed 3 times by same buffer solution for 35 mins, followed by fixation done with 1 per cent osmium tetroxide solution for 2 h further washed thrice using sterililized distilled water and then dehydrated in a crescent acetone solution series that is, 30, 50, 70, 85, 90 and 100 percent. The samples were then dried in a critical point dryer (Bal-tec CPD 030) with carbon dioxide. Finally, the specimens were spotted on aluminium stubs and fixed with double sided black tape and coated with 20nm gold layer with the help of vacuum evaporator (Bal-tec SCD 050). All specimens were visualized under Joel SEM- 6400JSM- 6360LV microscope (JEOL Ltd., Japan).

Qualitative analysis of phytochemical screening of different aqueous plant extract
The aqueous extract of five selected plants (D. stramonium, A. sativum, A. indica, E. globulus, and L. camera) was tested for anti-microbial secondary metabolites properties against test pathogen.

Alkaloids
1.5 ml extract was taken for alkaloid testing. 2 ml of 1 per cent HCL solution thoroughly mixed with test extract. After mixing, solution was heated for to 2 mins and Mayer’s reagent (6 drops) was added. Orange colour formation indicates the presence of alkaloids³¹.

Flavonoids
1 ml of aqueous solution of test extract was gently mixed with 1 ml of 10 percent lead acetone. Develop yellow colour that showed the presence of flavonoids³².

Saponins
The procedure described by Saidulu et al³³ was followed for the assay 2 ml of aqueous test extract was taken and mixed with 6 ml sterilized distilled water. Formation of forth was observed after 3 mins.

Steroids
0.5 ml test extract mixed with 2 ml of acetic anhydride solution and further 2 ml H₂SO₄ was added to the reaction. The colour change violet to green or blue expressed the presence of steroids³⁴.

Tannins
Few drops of ferric chloride solution was mixed with test extract. Development of blackish colour expressed the presence of tannins in the extract³³.

Terpenoids
2 ml test extract was mixed with 5 ml of chloroform and heated for 5 mins and then allowed to dry. Further 2 ml concentrated H₂SO₄ was added and again heated on low flame for 2 mins. Greyish colour develops to show presence of terpenoids³³.

Glycosides
Each test extract was hydrolysed with hydrochloric acid and then neutralized with NaOH solution. Red colour developed after Fehling’s solution A and B were mixed and this revealed that presence of glycosides³⁵.

Phenols
1 ml of test extract was extracted in ethanol and then evaporated till dryness. After drying residue was dissolved in sterile distilled water and add 0.5 ml Folin-ciocalteu reagent followed by 5 ml of 20% Na₂CO₃ solution. Bluish colour developed reveals that presence of phenols³⁶.

Quantitative analysis of phytochemical screening of different aqueous plant extract
Alkaloids test extract weighed 2 ml in to 250 ml capacity sterile conical flask. 200 ml glacial acetic acid in methanol was added and mixed gently. Flask were covered with aluminium foil and incubated at 35°C for 4 h. Then filtered obtained from previous step was and concentrated in water bath. Further few drops of concentrated NH₄OH were added into test extract for precipitation. The precipitate was extracted, washed with dilute NH₄OH and again filtered. The remaining residue was calculated in term of percentage³⁷.

Flavonoids
10 g each test extract was extracted with the 100 ml of 80 percent ethanol solution at 37°C. The obtained solution was filtered by the help of Whatman filter paper No. 42 and then filtrate placed into water bath for dryness. The wright of solution and percentage quantity was calculated according³⁸.

Saponins
20 g each dried sample and 20 per cent ethanol was added. Sample was incubated in water bath for 1 h with constant shaking. The solution filtered and residue again extracted with 200 ml of 20 percent methanol. The extracts were allowed to be reduced up to 40 ml in water bath. Concentrated solution placed into a 250 ml capacity separatory funnel, 20 ml diethyl ether was added and then vigorous shaking. Ether layer was formed and discarded, and purification process was repeated. After purification, 60 ml n-butanol was added and further extract were washed thoroughly twice with 15 ml of 5 percent NaCl. The solution was heated for evaporation, and then dried in hot air oven. Weighed and percentage was calculated of saponin³⁹.

Steroids
1 gm sample was crushed in 20 ml of methanol and filtered. 2 ml filtrate was taken and add 5 ml of chromagen solution. The solution was incubated at 35°C for 30 mins. Absorbance was recorded at 550 nm wavelength⁴⁰.

Tannins
500 mg samples were added in 50 ml distilled water. The solution allows to shaken for 60 mins and filtered. 10 ml filtrate was pipetted out into the new test tube and 2 ml 0.1 M ferric chloride in 0.1 N HCl was added along with 0.008 M potassium ferrocyanide. The final absorbance was recorded at 120 nm wavelength⁴¹.

Terpenoids
1 g of extracts were taken, crushed in 50 ml of methanol and filtered. 2.5 ml filtrate was taken and 2.5 ml of 5 % phosphomolybdic acid was added afterward 2.5 ml of concentrated H₂SO₄ were added. The mixture was incubated at 35°C for 30 mins. The final observance was recorded at 700 nm wavelength⁴⁰.

Glycosides
1 g test samples were taken and macerated with 50 ml of methanol and filtered. 1 ml supernatant was taken and 4 ml of alkaline pirate solution was added. The reaction mixture was heated for 5 mins and allowed to cool. The observance was recorded at 490 nm wavelength³⁴.

Phenols: 2 g test samples were taken in 100 ml diethyl ether solution and allowed to defat with help of Soxhlet apparatus for 2 to 3 h. Defatted solution was heated with 50 ml of ether for 15 mins. 10 ml of reaction was pipetted out into 50 ml capacity flask and 15 ml sterile distilled water was added. Further, 2 ml of NH₄OH solution and 2 ml of concentrated amyl alcohol were added. The reaction was incubated at 35°C for 30 mins. Absorbance was recorded at 505 nm wavelength⁴¹.

Statistical analysis
The analysis of data with help of one-way analysis of variance (ANOVA) and compared means for significance at p level of ≤ 0.05 through Duncan’s multiple-range test (DMRT) (IBM SPSS, Version 20).