Orius insidious (minute pirate bug) is a beneficial generalist predator that feeds upon adult and larval thrips. Orius are expensive to purchase, so some growers use ornamental pepper banker plants to provide a pollen food source to help them get established in the greenhouse. Growers rear the minute pirate bugs on pollen producing pepper plants and place plants throughout the greenhouse to distribute them. As long as the pepper plants are in flower and producing pollen, the minute pirate bugs will reproduce on them.
At the recent Northeast Greenhouse Conference and Expo, the “Advanced Biocontrol Panel” with Suzanne Wainwright-Evans, Buglady Consulting; Ron Valentin, Bioline Agrosciences and Jeff Marstaller, Cozy Acres Greenhouses, there were many excellent questions.
What about using wild collected lady beetles (a. k. a., ladybirds or ladybugs) for aphid control?
Here are a few take-home tips from the “Advanced Biocontrol Panel” with Suzanne Wainwright-Evans, Buglady Consulting; Ron Valentin, Bioline Agroscience and Jeff Marstaller, Cozy Acres Greenhouses.
It is a good time to clean empty greenhouses rather than to wait until just before starting spring production. Cleaning now helps to eliminate over-wintering sites for pests in unheated greenhouses, especially if the winter is unseasonably warm.
Two-spotted spider mites (TSSM) can develop quickly during hot dry weather like we have been having recently. Although we have not seen outbreaks yet this season, it is important to monitor for mites and treat when populations are low if using biological controls. Also, it is important to prevent outbreaks of two-spotted mite infestations prior to fall to minimize infestations next spring.
Potato aphids are common on ornamental plants. The potato aphid is pink or green (in this photo), with a darker stripe down its back (seen in related photo). Antennae are longer than their bodies, with long, black tipped cylindrical cornicles. This photo shows potato nymphs, shed skins and parasitized aphids. As aphids increase in size they shed their exoskeletons (cast skins) which are white and light weight. These white cast skins are often mistaken for whiteflies. The parasitized aphids (aphid mummies) appear as small brown swollen aphids.
The predatory mite Neoseiulus cucumeris is sold with a carrier that contain bran mites (photo) as a food source for the N. cucumeris. The bran mites tend to be white, covered with fine hairs and move more slowly than N. cucumeris.
Before releasing biocontrols, check with your supplier to determine if long residual pesticides have been applied to incoming plant material that may adversely affect the biological control agents. For successful thrips management using biocontrol, begin introductions of natural enemies on young plants or in propagation areas before thrips are detected.
Beneficial nematodes are an easy way to begin a biocontrol program in greenhouses. Beneficial nematodes (Steinernema feltia) are best applied as a media drench to target the fungus gnat larvae. Treat as soon as possible (2 to 3 days) after sticking cuttings, planting plugs or starting seeds.
Treatments for fungus gnats are best directed against the larval stage. Many growers use beneficial nematodes Steinernema feltiae sold under the trade names of Nemashield, Nemasys, Entonem or Scanmask applied as a drench. Fungus gnat larvae are killed in one or two days by the symbiotic bacterium that dissolves their internal contents.