# Preparation and Herbicidal Evaluation of Butyl Hydroxybenzoate Emulsion

## TL;DR

This study develops a new eco-friendly microbial herbicide using butyl hydroxybenzoate emulsion, showing effectiveness against weeds while being safe for certain crops.

## Contribution

The paper introduces a novel microbial herbicide based on butyl hydroxybenzoate with demonstrated field efficacy and crop safety.

## Key findings

- 0.75% BP emulsion significantly inhibits germination of several weed species without affecting Brassica campestris L. seeds.
- Field application of 1.00%–0.75% BP emulsion effectively controls weeds in wheat fields without harming the crop.
- BP emulsion shows high phytotoxicity to Cucumis sativus L. and Spinacia oleracea L., with leaf damage and death rates over 80%.

## Abstract

In order to develop a new environmentally friendly microbial herbicide for the field of weed control, this study used the metabolite butyl hydroxybenzoate (BP) of the HY-02 strain of Alternaria as the research object. The BP emulsion formula was determined to be a mixture of BP, methanol, and Tween-20 in a ratio of 1:1:2 g/mL. The seed germination inhibition effect, the phytotoxicity of living plants, crop safety, and the field effect of the emulsion were studied. Research has found that adding 0.75% BP emulsion to the seed culture medium inhibits the germination of weed seeds such as Amaranthus retroflexus L., Malva verticillata L. var., and Chenopodium album L. While Brassica campestris L. seeds were unaffected, Triticum aestivum L and Hordeum vulgare L. stem and leaf growth were inhibited. Cucumis sativus L., Lactuca sativa L. var. asparagina, Spinacia oleracea L., and Capsicum annuum L. seeds are significantly inhibited, with germination rates below 20%. We sprayed 0.75% BP emulsion onto live potted plants; among the weeds, the incidence of Amaranthus retroflexus L., Lepyrodiclis holosteoides, Thlaspi arvense L, Galium spurium L., Malva verticillata L. var. Crispa, Chenopodium album L., and Avena fatua L reached 100%. The Pisum sativum L. and Triticum aestivum L. crops were not affected (NS), and they had slight plant height inhibition and slight susceptibility (LS) to highland Hordeum vulgare L. and peppers. They were highly phytotoxicity to Cucumis sativus L. and Spinacia oleracea L. Some plant leaves became infected and died, with incidences of 85% and 82%, respectively. The field experiment showed that after diluting the BP emulsifiable concentrate, the seedling stage spray was inoculated into the Triticum aestivum L. field, and it was found that the BP emulsifiable concentrate at the concentration of 1.00%~0.75% had a herbicidal effect on weeds such as Chenopodium album L., Elsholtzia densa Benth, and Amaranthus retroflexus L. in the Triticum aestivum L. field, and it was safe for Triticum aestivum L. crops in the field. These results indicate that BP emulsion could be developed into a new environmentally friendly microbial herbicide for field application in grass (Triticum aestivum L. and Hordeum vulgare L.) crops. At the same time, BP’s excellent antibacterial, low-toxicity, hydrolysis, and other effects can promote diversification in herbicide development.