Studies on the role of aromatic shrubs in the inhibition of adjacent vegetation. Kotoulas V., Panagopoulos G., Skouras V., Economou G. and Karamanos J.A. Laboratory of Agronomy, Faculty of Crop Science, Agricultural University of Athens.

 The biodiversity of aromatic flora in Greece  Typical constituent element of Mediterranean ecosystem

Origanum hirtumOriganum onites

Coridothymus capitatusSatureja thymbra

 The classic uses - herbs - medicins - essential oils "Let food be thy medicine and medicine be thy food" Hippocrates, the Father of Medicine ( B.C.)

 The novel uses (industrial use) - pharmaceutics - cosmetics, - agriculture - antimicrobial - animal production

agriculture - antimicrobial - animal production QUESTION ? Inhibitory effect on weeds ?

 The inhibitory effect has been stated on oregano  Observation in situ

 To study the inhibitory effect of all the “origanum” species indigenous of Greek ecosystems and Mediterranean in general  The longterm aim their effective use in terms of weed control

Objectives  In situ assesement of inhibitory effect  In vitro biotests of their phytotoxicity

 Islands of the north-eastern Aegean sea Ikaria and Fournoi  4 aromatic species a. Origanum onites b. Origanum hirtum c. Coridothymus capitatus d. Satureja thymbra

I. Study of adjacent vegetation during surveys in localized aromatic habitats. Plot area: 15 m 2 (5m x 3m) Richness: Number of the species Coverage: (the vertical projection of plant canopy on the ground) Importance value: frequency + coverage (Wikum and Shanholtzer, 1978)

II. Biotests a. Avena radicle Determination of 50% inhibition in radicle elongation b. Spirodela polyrhiza chlorosis Determination of 50% Lethal Dose (LD 50% ) Doses: (ml of herbal distillate/ml of dilution) 1 (A) 0.5 (A/2) 0.25 (A/4) (A/8) (A/16) (A/32) (A/64) (A/128) Doses: (ml of herbal distillate/ml of dilution) 1 (A) 0.5 (A/2) 0.25 (A/4) (A/8) (A/16) Dose respone of herbal distillates

 Richness Origanum onites Origanum Hirtum Thymus capitatus Satureja thymbra Origanum onites111 Origanum hirtum101 Thymus capitatus101 Satureja thymbra111 Ditrichia viscose1111 Ruta graveolens1001 Euphorbia cyparissias1000 Lupinus angustifolius0011 Pteridium aquilinum1110 Arbutus unedo1111 Erica manipuliflora1111 Rubus fruticosis1100 Hypericum perforatum1011 Vitex agnus-castus1000 Salvia officinalis1111 Lavandula vera1111 Spartium junceum1111 Sarcopoterium spinosum 1111 Helichrysum angustifolium 1011 Cistus parviflorus1111 Quercus coccifera1011 Avena barbata1111 Oryzopsis miliacea1111 Hordeum murinum1111 Silybum marianum1010 Pistacia lentiscus0010 Chrysanthemum coronarium 1011 Vicia sativa0001 Total241521

a. Origanum onites

b. Origanum hirtum

c. Coridothymus capitatus

d. Satureja thymbra

Average radicle length of oat (cm) Herbal distillate C a (ml/ml) O. onitesS. thymbraO. hirtumC. capitatus Control11,07 (0) b 11,07 (0) 0,0087,09 (36)9,14 (17)9,54 (14)7,04 (36) 0,0168,62 (22)8,36 (24)6,59 (40)8,98 (19) 0,0316,23 (44)8,30 (25)1,79 (84)6,85 (38) 0,0620 (100)0,55 (95)0,25 (98)1,61 (85) 0,1250 (100) 0,250 (100) 0,50 (100) 1 ld 50 c 0,18 (ab) d 0,22 (c)0,16 (a)0,20 (bc) a Concentration (ml/ml), b numbers in parentheses indicate percent inhibition, concentration of the allelopathic components to cause 50% inhibition of radicle growth as determined by probit analysis. d Means with the same letter are not significantly different (LSD, P < 0.05).

Response of Spirodella polyrhiza to herbal distillates Leaf chlorosis b Herbal distillate C a (ml/ml) O. onites S.thymbra O. hirtum C. capitatus Control1111 0, , , , ld 50 0,330,370,160,27 a Concentration (ml/ml), b the European Weed Research Society classification scale of phytotoxicity (1: no symptoms, 9: heavy damage to total kill).

 In situ observations Lower richness in O. hirtum Lower importance value in O. onites

Biotests  O. hirtun showed the higher inhibitory effect

The identification of the effective constituent  The future effective use  The effective application on farm for weed control