Limonene in Marigolds Protects Tomato Plants from Whiteflies

Researchers at Newcastle University have published a study in PLOS ONE, showing that limonene is the component of marigolds that repels tomato whiteflies. The research team says it could be possible to develop a limonene product that could be hung in greenhouses to deter whiteflies. Study leader Dr. Colin Tosh commented, “There is great potential to use limonene indoors and outdoors, either by planting marigolds near tomatoes, or by using pods of pure limonene. Another important benefit of using limonene is that it’s not only safe to bees, but the marigolds provide nectar for the bees which are vital for pollination.” The team is conducting further studies on developing a three-companion-plant mixture to repel three major insect pests of tomato: whiteflies, spider mites, and thrips.