Contribution to the fight against post-harvest rot of tomato fruits (solanum lycopersicum.) Through the use of the aqueous extract of ageratum conyzoides

Tomato production in Cameroon faces numerous constraints, including post-harvest rot. This study was carried out with the aim of contributing to the fight against post-harvest rot of tomato fruits through the use of the aqueous extract of Ageratum conyzoides. To achieve this objective, the pathogen responsible for tomato fruit rot was isolated and the microscopic and macroscopic characters determined; the antifungal activity of the aqueous extract of A. conyzoides was evaluated in vitro using three doses (30, 60, and 120 mg/ml) with three repetitions at three different periods (before, during and after) fruit treatment by the extract and inoculation of the pathogen on scarified and non-scarified fruits. A synthetic fungicide Pencozeb served as a positive control. Parameters such as mass loss of tomato fruits, surface area of lesions induced on scarified and non-scarified tomato fruits, were measured using a balance and graph paper respectively. The results show that Fusarium oxysporum was the pathogen responsible for rotting tomato fruits and having the macroscopic characteristic of a cottony texture and a white aerial mycelium, macroscopically, Fusarium oxysporum presents two types of asexual spores, namely macroconidia which are curved, pale-colored spores, and microconidia which are ovoid spores with septate and branched hyphae, a smooth and thin cell wall. The antifungal test revealed that the aqueous extract showed an effect inhibitor on the development of the lesion surface and mass loss at the highest dose 120 mg/ml when the extract applied twenty-four hours (24 hours) before inoculation on the fruits was fungicides at a concentration of 120 mg/ml on Fusarium oxysporum. The pathogen-induced lesion area and mass loss of scarified tomato fruits were 6.000±3.09 and 10.04±9.37 respectively. In non-scarified fruits these values were 8.45±3.43 and 48,000±13.66 respectively for lesion area and mass loss. This extract can therefore be used as an alternative to chemical pesticides in fruit preservation