# In Vitro Assay Using Proboscidea parviflora W. and Phaseolus lunatus L. Plant Extracts to Control Pythium amazonianum

## TL;DR

This study explores using plant extracts to control a fungal disease affecting avocado trees, offering an eco-friendly alternative to synthetic fungicides.

## Contribution

The study introduces two plant extracts as potential alternatives to synthetic fungicides for controlling Pythium amazonianum.

## Key findings

- Extracts from Proboscidea parviflora and Phaseolus lunatus inhibit mycelial growth of Pythium amazonianum in vitro.
- Phaseolus lunatus extract shows higher efficacy at lower concentrations than Proboscidea parviflora extract.
- Both plant extracts are promising for controlling avocado tree wilt without harming beneficial microorganisms.

## Abstract

Avocado tree wilt is a disease caused by Phytophthora cinnamomi Rands. Recently, this disease has been associated to Pythium amazonianum, another causal agent. Avocado tree wilt is being currently controlled with synthetic fungicides that kill beneficial microorganisms, polluting the environment and leading to resistance problems in plant pathogens. The current research work aims to provide alternative management using extracts from Proboscidea parviflora W. and Phaseolus lunatus L. to control the development of mycelia in P. amazonianum in vitro. Raw extracts were prepared at UAAAN Toxicology Laboratory, determining the inhibition percentages, inhibition concentrations and inhibition lethal times. Several concentrations of the plant extracts were evaluated using the poisoned medium methodology, showing that both extracts control and inhibit mycelial development, in particular P. lutatus, which inhibits mycelial growth at concentrations lower than 80 mg/L, being lower than P. parviflora extracts. These extracts are promising candidates for excellent control of Pythium amazonianum.