Dissertation
Trichome mimics: Sprayable plant-based adhesives for crop protection against thrips
Sprayable plant-based adhesives for crop protection against thrips Some plants, such as sundew and tomato, protect themselves with sticky hairs that repel or even trap arthropod herbivores.
- Author
- T.V. Bierman
- Date
- 10 February 2026
- Links
- Thesis in Leiden Repository
Some plants, such as sundew and tomato, protect themselves with sticky hairs that repel or even trap arthropod herbivores. Most agricultural crops lack this characteristic. Therefore, research was conducted to determine whether sprayable adhesive droplets made from plant oils are effective in protecting plants against the Californian thrips (Frankliniella occidentalis), a globally significant pest insect. The idea was to cover chrysanthemums (the model plant) with plant-based adhesive droplets that would trap the thrips. In initial tests, in which filter paper and loose leaves were sprayed with adhesive droplets, adult thrips were easily trapped, especially in larger droplets made from rice germ oil, among other substances. The glue droplets were less effective on whole plants: even with the most liquid glues that covered the plants well, at most 5% of the thrips were caught. However, glue-sprayed plants did suffer up to 50% less damage than water-sprayed control plants. Further study of the metabolome of sprayed plants showed that not only the glue droplets but also the spray solution reduced thrips damage. Glue-treated plants showed the strongest changes in concentrations of metabolites involved in general stress and anti-herbivore responses. The glue therefore has both a direct and indirect anti-thrips effect by stimulating the plant's defences. The effect on natural enemies was also investigated. The predatory mite Transeius montdorensis and the predatory bug Orius laevigatus were able to avoid the glue effectively and remained effective in suppressing thrips even on glue-sprayed plants. Plant-based, sprayable glues therefore appear to be a promising sustainable crop protection product, although further development is needed to make them truly effective as physical traps.