# The Fungicidal Effect of Essential Oils of Fennel and Hops against Fusarium Disease of Pea
## 3 Results and discussion
### Determination of Antifungal Activity In Vitro
The essential oil of fennel seeds grown in Poland completely inhibited the growth of _S. scleroorum_ and reduced the growth of _R. solani_ and _B. cinerea_ by 80% and 60%, respectively. In contrast, oil from fennel seeds grown in Egypt had no effect on _S. scleroorum_ and inhibited the growth of _R. solani_ and _B. cinerea_ by only 16.6% and 20.0%, respectively. At a concentration of 1000 ppm, both oils had different effects on the growth of three _Fusarium_ species. The oil extracted from the fruits of _F. vulgare_ grown in Poland was most effective against _F. graminearum_ (MGI of 48.8%), followed by _F. avencecum_ (13.3%) and _F. culmorum_ (6.2%) [49]. Egyptian fennel essential oil was also most effective against _F. graminearum_, but the reduction in mycelial growth was only 28.8%. Egyptian fennel oil inhibited the growth of _F. culmorum_ by 14.0% and had no effect on _F. avencecum_[49]. According to the literature, the percentage content of essential oil constituents is influenced by: (i) variety, (ii) chemo-type, (iii) ontogeny, (iv) plant organs, (v) harvest time, (vi) latitude and environmental conditions, (vii) nutritional status of plants, (viii) harvest date and drying conditions, and (ix) extraction methods and conditions [30; 38; 52; 53]. Essential oils extracted from seeds of 16 wild populations of _F. vulgare_ in Tunisia (subhumid, middle and upper semi-arid and humid climates) contained mainly phenylproapions with a dominance of estragole (66.09-85%), but they differed considerably in the content of phenolic compounds [54]. Essential oils from _F. vulgare_ populations growing in different regions of Iran were characterised by different contents of trans-anethole (46.5-84%) and fenchone (9.1-23.8%) [55]. [PERSON] et al. [56] demonstrated that essential oils isolated from fruits of _F. vulgare_ with different phenological patterns and different origins can show significant differences in the content of trans-anethole, estragole, fenchone and \(\alpha\)-phellandrene. [PERSON] and [PERSON] [57] found that the variety has a greater influence on the chemical composition of HEO than the growing conditions or the processing and storage methods. Similar conclusions were formulated by [PERSON] et al. [58], who observed correlations between _H. lupulus_ cultivars and plant age as well as hydrocarbon and oxidised compounds. Essential oils extracted from the fruits of three organically grown fennel cultivars (_F. vulgare_ var. _azoricum_, _F. vulgare_ var. _dulce_ and _F. vulgare_ var. _vulgare_) in Egypt contained 18 monoterepnoids, with trans-anethole, estragole and fenchone dominating [59]. In the above study, FEO was characterised by similar antimicrobial activity against gram positive and gram negative bacteria, _A. niger_ and _C. albicans_, despite differences in the chemical composition of the oils extracted from the different varieties. Research has also shown that the overall antifungal activity of essential oils significantly exceeds the individual effects of even the most potent compounds [30; 60]. The biological activity of essential oils seems to be determined by the synergistic effect of all ingredients [61; 62]. [PERSON] et al. [63] found that HEO strongly reduced (85-100%) the mycelial growth of _Zymoserporia tritici_, while the three main constituents of HEO (\(\alpha\)-humulene, mycrene and trans-caryophyllene) with proven antimicrobial potential showed no significant activity in single tests. These results confirm that the synergistic interactions between the essential oil components significantly enhance the biological activity of the oil. In the current study, the overall effect of the essential oils was investigated rather than their individual components. The plants studied (_F. vulgare_ and _H. lupulus_) were organically grown in northeastern Poland, which is characterised by a low level of urban and industrial development. According to [PERSON] et al. [64], the differences in the sensitivity of _Fusarium_ species to essential oils could be due to the unique properties of these pathogens.