Evaluación de extractos acuosos de ruda y canela sobre el crecimiento micelial de moniliopthera roreri a nivel in vitro.

Abstract

It is believed that the origin of cocoa is located in Mesoamerica, where we find evidence of its use around 2000 years BC, in Ecuador cocoa trees are observed for the first time with the arrival of the Spanish on the Pacific coast, currently cultivated 2 types of cocoa, the national and CC-N51. Cocoa is a semi-deciduous tree with dark bark (gray-brown) with brown, hairy branches. The leaves are simple ovate, alternate and engraved, 17 to 48 cm long and 7 to 10 cm wide. The flowers are hermaphrodite, pentamerous, actinomorphic, 10 to 20 mm in diameter, its inflorescences are cauline (on the stem). The fruit is a cob, purple or yellow at maturity of 20 or 35 cm long and 7cm wide, 5 to 10 longitudinal grooves. The seeds are reddish brown, ovate in shape and measure about 20, 30 and 50 mm long, 12 to 16 mm wide and 1 to 12 mm thick. World production is centered in Africa with 66%, in Ecuador cocoa plantations are distributed in 16 provinces and occupy a planting area of 500,000 hectares. Cocoa cultivation faces different environmental, technological, economic and social factors, which are accompanied by phytosanitary problems such as diseases that are the main reason for the loss of cocoa plantations and low yields in production. The methods currently used for the control of fungal diseases are those of synthetic type, which by their high cost are rarely used, there are different investigations in the use of biological alternatives for the control of these diseases, one of them is the use of plant extracts that contain secondary metabolites in its composition with antifungal action. Moniliasis is a disease caused by the fungus Moniliophthora roreri and is considered as the most destructive in the cocoa sector, it causes internal and external necrosis of the fruits, its inoculum can survive more than seven months in mummified pods spreading the fungus at the time of fruiting of pods. A characteristic of the fungus is the long incubation period, the time that lasts the infection can be from 3 to 8 weeks depending on the severity of the attack, susceptibility of the tree, age of fruits and climatic conditions. The extracts of botanical origin have as main characteristic the presence of secondary metabolites which form defense strategies in the plant, among the compounds that have effect in the control of microorganisms are: flavonoids, phenols, terpenes, alkaloids, lectins and polypeptides. The oils or extracts of cinnamon are constituted by 65 to 75 % of cinnamic aldehyde and 5 to 10 % of eugenol, which fulfills the function of stopping the invasion of species of fungi, in the elaboration of the extract of rue we have found substances like rutin and inulin that have demonstrated a nematicide effect, also the rue is composed by secondary metabolites like alkaloids and flavonoids. In this research work the use of aqueous extracts of cinnamon, rue and a combination of both, in different doses to evaluate the mycelial growth of the fungus in in vitro culture is proposed. The treatments to be evaluated are the following: T1 90ml PDA + 10 ml EAC, T2 80 ml PDA + 20 ml EAC, T3 70 ml PDA + 30 ml EAC, T4 90 ml PDA + 10 ml EAR, T5 80 ml PDA + 20 ml EAR, T6 70 ml PDA + 30 ml EAR, T7 90 ml PDA + 10 ml EACR, T8 80 ml PDA + 20 ml EACR, T9 70 ml PDA + 30 ml EACR and treatment 10 corresponds to the control. This research was developed in the laboratory of Phytopathology belonging to the Faculty of Agricultural Sciences of the Technical University of Machala, to obtain the extracts three Erlenmeyer flasks were used where the fresh material was placed, it was weighed and in each container was deposited 60gr of cinnamon/300ml of distilled water, 60gr of rue/300 ml distilled water and a combination of 30gr of cinnamon-30 gr of rue/300 distilled water, the weight/volume ratio was 1:5. Once the extracts were prepared, they were autoclaved for 45 min. In laboratory conditions the treatments T2 (EAC at 20%) and T3 (EAC at 30%), were the ones that presented the best results in the control of radial growth of M. roreri, it is also observed that the higher the proportion of EAR, the higher the efficiency of T6 (EAR at 30%). The results show us that we must continue on the path of research to achieve sustainable agriculture, to minimize and reduce the use of synthetic products, which can cause negative environmental impact.