Evaluación de extractos acuosos de manzanilla y ajo sobre el crecimiento micelial de moniliopthora roreri a nivel in vitro

Abstract

Cocoa (Theobroma cacao L.) is a herbaceous tree that belongs to the theobroma genus. Worldwide, cocoa production annually is 4.3 million tons of cocoa beans, of which 74.9% are concentrated in West Africa, 12.1% in Southeast Asia and 13% in Latin America. The main cocoa producers in Latin America are Brazil, Ecuador, Peru, Colombia, Venezuela, and Trinidad & Tobago. In Ecuador, the cocoa sector grew by 10% and exports reached 260 thousand metric tons (87% grain and 13% derived products). In Ecuador, cocoa production is located in 23 of the 24 provinces, Esmeraldas, Manabí, Pichincha and Cotopaxi occupy 80,000 planted hectares. The main diseases in Latin America that attack cocoa plantations are: witches' broom (Moniliophthora perniciosa) and moniliasis (Moniliophthora roreri, in Ecuador witches' broom affected 60 to 70% of production, and moniliasis caused losses of up to 80% in cocoa plantations Cocoa moniliasis is a disease caused by the fungus (Moniliophthora roreri), this disease originated in northeastern Colombia and in Ecuador was detected for the first time in 1917. The spores of the fungus attack the fruits depending on the age and environmental conditions causing deformations, brown spots covered with a white mycelium, wilting and necrosis of the fruit completely. The main controls for moniliasis that are put into practice are cultural, chemical and biological control, the associated integrated management of climatic factors has shown a reduction of the disease by 40%, another alternative is the use of antagonistic fungi such as Bacillus subtilis to control phytopathogens in crops of economic importance, in addition to chemical control it is suggested to use Chlorothalonil, a broad-spectrum non-systemic fungicide. Plant extracts are an alternative to organic agriculture, due to their effectiveness in controlling pests, diseases and weeds. Based on the problems experienced by small and large cocoa producers by not having efficient control and management for moniliasis, the use of botanical extracts is proposed as a cultural alternative against phytopathogenic fungi, for which different treatments of ethanolic extracts will be used. to inhibit the mycelial growth of the fungus (Moniliophthora roreri), at in vitro level. The study was carried out in the plant pathology laboratory of the Faculty of Agricultural Sciences belonging to the Technical University of Machala. 1500 ml of potato-destroza-agar (PDA) culture medium was prepared, of which we used 820 ml for our experiment. For the selection of plant material, an analysis of scientific articles was carried out where they used botanical extracts of plant origin that showed favorable results in their studies for the control of phytopathogenic fungi and their inhibition of radial growth at the in vitro level. The selected plants were: Garlic (Allium sativum) - Chamomile (Chamaemelum nobile). The dosage was carried out as follows, in 10 glass containers with established measures of 70-80-90 ml pda, 10-20-30 ml of the garlic extract, chamomile and the combined extract were placed according to the treatments and a bottle of 100 ml of pda as a control to show the significant difference in relation to the control, once finished, the plating and sowing of the inoculum is carried out. Under controlled laboratory conditions, the treatments that showed the greatest inhibitory effect T6 (aqueous extract of garlic at 30%), T5 (aqueous extract of garlic at 20%) and T9 (aqueous extract of garlic-chamomile at 30%) are statistically equal. and superior to the rest of the treatments.