Antifungal Potential of Three Plant Extracts in the Control of Some Major Fungi Associated with Cashew Seeds (Anacardium occidentale L.)

Abstract

Cashew (Anacardium occidentale L.), is an economically export oriented crop that could plays an important role in the Cameroonian economy. Owing to its importance, a study was carried out to evaluate the potential antifungal activities of three plants extracts against three major fungal pathogens associated to its seeds. To achieve this objective, cashew seeds samples were collected from Cameroon and Chad, and fungal pathogens isolated on Potato Dextrose Agar (PDA) culture medium. In vitro antifungal activities of Callistemon viminalis, Cupressus lusitanica and Lantana camara were assessed on three major fungi; Cercospora sp., Colletotrichum gloeosporioides and Pestalotia heterocornis. Results showed that cashew seeds harbour a diversity of fungal species; the most frequent are Cercospora sp. (26%), followed by Aspergillus niger (17.78%) and P. heterocornis (15.6%). Aqueous extracts at 28 mg/ml and ethanolic extracts at 16 mg/ml of C. lusitanica and L. camara, inhibited at 100%, the radial growth and sporulation of all tested fungi. This preliminary work has opened up a possibility of the use of these extracts in the treatment of seed-borne fungi of cashew nuts. However further studies are still on-going under in vivo field conditions to practically evaluate on their potential in cashew seeds disease management.

Inventory and Management of Fungi Associated with Banana Plant through the Use of <i>Allium ampeloprasum</i> and <i>Cymbopogon citratus</i> Extracts

“…Explants on Petri dishes with 100% inhibition were transplanted onto extract-free PDA medium to demonstrate fungistatic or fungitoxic activity. The fungistatic activity observed with Allium ampeloprasum extracts are similar to that reported by [11] who showed that Erigeron floribundus and Euphorbia hirta extracts had fungistatic activity on the fungi associated with avocado. In addition, the results are also similar to those of [28], reported that Cupressus lusitanica extracts had fungistatic activity on the growth of Phytophtora colocasiae, the agent responsible for taro blight.…”

“…1 ml of each extracts at different concentrations were incorporated into 19 ml of PDA and poured into sterilised Petri dishes of 90 mm diameter and allowed to solidify in a fume hood which was lighted by flame from a Bunsen burner. After solidification, mycelia discs (5 mm) of 10-days old growing in pure cultures of each fungus were transferred to the Petri dishes with the help of a cork borer of 5 mm in diameter [11]. PDA plates mixed with fungicide (Dithane) at the recommended dosage of the producer (1 mg/ml) served as the positive control while distilled water served as the negative control.…”

“…Confronted with these diseases, management is often done through the usage of chemical fungicides. Nonetheless, not only is there a continuous increase in the cost of these chemical fungicides, they induce a certain number of problems like environmental pollution, development of resistance by the fungi and the presence of chemical residues in the fruits which are potentially detrimental to the health of the consumers and workers [11]. Hence, it is important to develop other alternative methods of control other than the use of chemical fungicides.…”

“…Among these alternative methods, the control method through the usage of natural products is the most recommended. The utilization of natural products, especially plant extracts, has been shown to be effective against many plant pathogens and considered to be safe for consumers and the environment [11]. The works of [12] are reported that aqueous and ethanol extracts of Cymbopogon citratus inhibit the development of Colletotrichum kahawae, causal agent of anth-racnose berry coffee.…”