Evaluation of companion plant effects on the management of herbivorous pests in tomato (in Greek)

This is a scientific poster presented at the 20th Panhellenic Entomological Congress, Mytilene, 20–24 October 2025, by researchers from the Democritus University of Thrace and a private agri-company in Imathia.

Topic: Whether flowering companion plants can boost the biological control of tomato pests by two zoophytophagous predators — Macrolophus pygmaeus and Nesidiocoris tenuis.

Companion plants tested: Fagopyrum esculentum, Lobularia maritima, Phacelia tanacetifolia, Calendula officinalis

Target pests: Tetranychus urticae (spider mite), Bemisia tabaci (whitefly), Phthorimaea absoluta (tomato leafminer)

Key findings:

Lab experiments (cage conditions): Presence of flowering companions had a positive effect on N. tenuis populations but not on M. pygmaeus. Pest populations (T. urticae, B. tabaci) were reduced in N. tenuis treatments with companion plants, but not to satisfactory control levels. No effect was detected on P. absoluta under either predator.

Field experiment: Calendula officinalis increased predator concentration near tomato plants and contributed to maintaining T. urticae infestation at low levels. F. esculentum and L. maritima showed less consistent field effects.

Overall conclusion: Companion plant effects are species-specific — both regarding which predator benefits and which pest is suppressed — indicating that no single companion plant strategy is universally effective. Further evaluation under varied conditions is recommended.

Funding: PRIMA Programme (Article 185 initiative), co-funded by Horizon 2020 (PRIMA2021-05), via the Greek General Secretariat for Research and Technology.