# Major Components of Dittrichia viscosa (Asteraceae) as a Source of New Pesticides

## TL;DR

This study explores natural compounds from Dittrichia viscosa to develop new, sustainable pesticides effective against pests and ticks.

## Contribution

The paper introduces new pesticide candidates derived from natural compounds of Dittrichia viscosa with diverse biocontrol applications.

## Key findings

- Compound 11 showed antifeedant and nematicidal properties against pests.
- Compounds 3a and 8 were potent antifeedants against Rhopalosiphum padi.
- Compound 29 was six times more larvicidal against ticks than the control nootkatone.

## Abstract

Ilicic acid, nerolidol, and 9-hydroxynerolidol are major components of the aerial parts of Dittrichia viscosa. These components were selectively isolated in multigram quantities and used as lead compounds to generate diversity in the search for new natural-product-derived pesticides. A total of 29 derivatives of these three molecules—some of which are known natural products—were generated by subjecting these natural products to different transformations. In order to explore potential applications in sustainable biocontrol, some of the compounds generated were evaluated for plant protection potential against insect pests (Spodoptera littoralis, Myzus persicae, Rhopalosiphum padi), against the nematode Meloidogyne javanica, and for their phytotoxic effects on ryegrass (Lolium perenne) and lettuce (Lactuca sativa). Additionally, their effects against the tick Hyalomma lusitanicum have been tested. Compound 11 was found to be antifeedant against S. littoralis and nematicidal. Compounds 3a and 8 were potent antifeedants against R. padi. None of the tested compounds significantly inhibited lettuce growth, and compounds 17, 3, and 3a even promoted root development. Conversely, compounds 3, 4, 11, 17, and 21a exhibited strong herbicidal activity on ryegrass. In larvicidal assays against H. lusitanicum, compounds 3, 3a, 11, 17, 29, and 33 were active, with compound 29 being six times more active than the positive control nootkatone.