Greenhouse observations from this week's NE Floriculture Update include:
- Botrytis, Whitefly, and Powdery mildew on tomatoes
- Thrips on cukes
- Leaf spot on eggplant
- Aphids on peppers
Pest Message, Week of May 14, 2012
Jim Mussoni, IPM Consultant, reports the following information on greenhouse vegetables this week.
- Botrytis was observed on leaves and fruit of greenhouse tomatoes. See photos. See previous message from Rich McAvoy, UConn about foliar diseases on greenhouse tomatoes and how to manage them. Also see chart of fungicides labeled for greenhouse vegetables including organic fungicides.
- Whitefly on greenhouse tomatoes were beginning in one greenhouse this week. See photos. Beginning with a clean greenhouse and clean plants are key. If infested, greenhouse whitefly is usually the species, although they can also be infested by sweetpotato whitefly. It is important to identify the species to if using biological control. Eretmocerus and Encarsia (parasitic wasps) can be used individually or together, if needed. Encarsia formosa is used to manage greenhouse whiteflies. Here is a good fact sheet: Biobest Crop Info-Sheet: Biological Control in Greenhouse Tomatoes List of pesticides for whiteflies on greenhouse tomatoes (from New England Vegetable Guide)
- Thrips were found in one greenhouse on cukes. Organic growers can try spinosad (Entrust) or one of the azadirachtin products and non-organic growers could try chlorfenapyr (Pylon). See chart for more options.
- Leaf spot was seen on greenhouse grown eggplants at a grower. Bacillus subtilis (Cease) is an option for organic growers. See chart of fungicides labeled for greenhouse vegetables including organic fungicides.
- Aphids were found on greenhouse peppers in several greenhouses.
- Powdery mildew was seen at one greenhouse on greenhouse tomatoes. Potassium bicarbonate (Milstop) is an option for organic growers.
Other notes of interest
- Powdery mildew on Rosemary: One grower reported that Milstop at the 1 T per gallon rate worked well. Cease also worked at the high label rate – Both organic products. In his experience, common rosemary appeared to be more susceptible and the cultivar ‘Barbeque’ seemed to be very tolerant to powdery mildew.
- Russ Norton (new Extension Horticulturist for Cape Cod -Barnstable County) reported seeing Downy mildew on seed propagated Coleus this week at a garden center and the UMass Diagnostic lab reported DM on the vegetative Coleus 'Life Lime' . See photos of DM on Coleus.
