Orius insidiosus, a pirate bug, is a tremendous ally in the greenhouse, providing biological control of thrips, aphids and mites. A great way to attract and keep Orius in the greenhouse is to have blooming marigolds there as habitat and food source, Carol Glenister of IPM Laboratories Inc. writes in Passages, the newsletter of the Pennsylvania Association for Sustainable Agriculture.
Marigold can serve as a banker, indicator and trap plant in biocontrol. A banker plant attracts and supports many greenhouse beneficials, allowing them to increase in number by providing habitat and food. Indicator plants entice both beneficial and pest insects so that you can monitor their populations in the greenhouse. Trap plants lure pests to one location where biological or chemical controls can be applied.
Orius can survive and multiply on pollen until prey become available. For that reason, it pays to have marigolds blooming and bring in Orius – either purchased or naturally – before your crops are likely to be affected by pests. Marigolds offer abundant pollen, bloom all season long and have tightly packed petals, which make it attractive to thrips and Orius, both of which like to squeeze into tight places. Yellow marigolds are especially attractive to thrips, perhaps even more so than yellow sticky cards.
For more on biocontrol, contact Carol Glenister, entomologist at IPM Laboratories Inc, 315-497-2063 or carolg@ipmlabs.com.