Nematicidal Effect of Eupatorium odoratum Linn. Aqueous Extract on Burrowing Nematodes (Radopholus similis) and its Application to Control Toppling Disease on Cavendish Banana (Musa acuminata)

Figure 1.

Figure 2.

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Mortality percentages of Radopholus similis as influenced by aqueous extract of leaves and stems of Eupatorium odoratum at different dilutions

Trait	Treatments (mg DW·L−1)
	water	fenamiphos (4.65 mg·mL−1)	EAEO12500	EAEO6250	EAEO3120	EAEO1560	EAEO780
Number of dead nematodes	129 ± 2.5a	761 ± 4.5k	723 ± 6.8f	624 ± 6.8e	512 ± 5d	409 ± 6.7c	282 ± 7.5b
Mortality (%)	16.1 ± 0.3a	95.1 ± 0.6k	90.1 ± 0.7f	78 ± 0.9e	64 ± 0.6d	51.1 ± 0.8c	35.3 ± 0.9b

Effects of the treatments on the growth parameters of banana plant

Trait	Treatments (mg DW·L−1)
	water	fenamiphos (4.65 mg·mL−1)	EAEO12500	EAEO6250	EAEO3120	EAEO1560	EAEO780
Pseudostem length (cm)	67.8 ± 2a	95.9 ± 3.1d	92.7 ± 2d	86.6 ± 2c	82.6 ± 2.1c	78.6 ± 2b	75.9 ± 2.4b
Girth (cm)	23.4 ± 1a	28.6 ± 1e	27.4 ± 1cde	28.2 ± 1.6de	26.6 ± 1.1bcd	25.4 ± 1.1bc	25.9 ± 1b
Leaf numbers	8.3 ± 0.6c	6.3 ± 0.6a	6.7 ± 0.6ab	7 ± 1ab	7.3 ± 0.6abc	7.7 ± 0.6bc	7.7 ± 0.6bc
Leaf area (cm2)	2071.7 ± 23.7a	2589.3 ± 36.6e	2510.3 ± 27.5d	2490.3 ± 34.8d	2397.7 ± 43.9c	2341 ± 29.5bc	2286.7 ± 36.3b

Components of aqueous extracts of leaves and stems of Eupatorium odoratum

Chemical compound	Test	Observations	Presence in EAEO
Tannin (Braymer test)	2 mL extract + 2 mL H2O + 2–3 drops FeCl3 (5%)	green precipitate	+
Flavonoid	1 mL extract + 1 mL Pb(OAc)4 (10%)	yellow	+
Terpenoid	2 mL extract + 2 mL (CH3CO)2O + 2–3 drops conc. H2SO4	dark red	+
Saponins (foam test)	5mL extract + 5 mL H2O + heat	foam	+
Steroids (Salkowski test)	2 mL extract + 2 mL CHCl3 + 2 mL H2SO4 (conc.)	sepia circle at the junction	−
Glycosides (Liebermann test)	2 mL extract + 2 mL CHCl3 + 2 mL CH3COOH	purple to blue to green	−
Alkaloids (Hager test)	2 mL extract + few drops of Hager’s reagent	yellow precipitate	+
Phenols	2 mL extract + 2 mL FeCl3	bluish color	+
Coumarin	1 mL extract + 1 mL NaOH 10%	yellow formation	−