You’ve likely noticed by now that thrips populations are especially high because of thehot, dry summer. Many growers are noticing their usual biocontrol programs can’t keep up, and further defenses are needed this year.
The use of mass trapping strategies may be the key to getting an edge over thrips. This post discusses the latest research on mass trapping of thrips in ornamentals, including patterned sticky tapes and the use of pheromones.
Now that the warm weather is finally upon us, it’s time to start worrying about thrips control.
What we’ve learned over the years is that pesticides just don’t cut it – the only reliable chemical for western flower thrips in Ontario is DDVP, which requires constant application. This means biological control is your best bet. Here’s a summary of the most effective tools, tricks, and timing, to ensure your biocontrol dollars are well spent.
Entomopathogenic nematodes – used to control fungus gnats, shoreflies and thrips – are often a “gateway bio” into biocontrol use in greenhouses. This is because not only are they effective and easy to use, but they’re generally compatible with insecticide use. Readily applied with regular spray equipment or through drip lines, nematodes can even be tanked mixed with pesticides to save on labour costs.
In this post, I’ll share some of my research at NC State, looking at which commonly used pesticides in Canadian and U.S. greenhouses are safe to use with nematodes.
The ice storm that passed through Ontario late last week may have disrupted more than just your travel plans. If your power went out, and your generator didn’t kick on right away your greenhouse might have dipped in temperature overnight, leading to possible cold or chilling injury. Continue reading “Recognizing Cold Injury”→
Effective biocontrol programs for western flower thrips often usemultiple natural enemies. These includepredatory mites like N. cucumeris or A. swirskii, but also generalist predators like Atheta and Orius, which can feed on mite eggs and nymphs.
It’s that time of year again, when baskets of Million Bells (Calibrachoa) are going up in the greenhouse. Here’s how to deal with and prevent some of their most common issues.
From a nutritional standpoint, the best thing you can is keep the pH of your calibrachoa in its ideal range; between 5.5 and 6.0. A pH higher than this can inhibit nutrient uptake, especially micronutrients such as iron.
Iron deficiency can be difficult to distinguish from other issues (like Black Root Rot – see below), but typically leads to yellowing of new growth. Leaves may only show chlorosis between the veins, or it may be spread throughout the leaf. This is different from nitrogen deficiency where yellowing occurs in the oldest leaves. If iron deficiency occurs, adding a chelated form of iron is best for uptake.
Yellowed plant growth (yellow circle) and dead plugs (orange circle) on a plug tray of Callibrachoa from black root rot.
Million bells are also highly susceptible toBlack Root Rot (Thielaviopsis) – I’ve seen this take out a good chunk of a crop. Symptoms include:
Stunting of foliage and roots
Plants in a tray will have uneven heights
black areas on roots
yellowing of leaves
Prevention is worth a pound of cure with this disease, as it is difficult to eradicate once established. Important steps to take include:
Proper Sanitation. To avoid an issue with Black Root Rot year after year, immediately dispose of diseased plants, limit water splashing, and sanitize benches, floors and used pots/plug trays. Always physically wash surfaces with a cleaner to remove organic matter, then follow up with a disinfectant such as KleenGrow (ammonium chloride compound).
Consider prophylactic applications of fungicides onplug trays. Products include Senator (thiophanate-methyl) or Medallion (fludioxonil). Preventative applications are an especially good idea if you’ve issues in the past. Adding bio-fungicides containing Trichoderma harzianum(e.g. Rootshield, Trianum) may also help.
Lowering your pH. This diseaseis significantly inhibited by a lower pH – between 5.0 and 5.5.
Manage fungus gnats and shoreflies, since these insects can spread Black Root Rot between plants. Treatments include nematodes, Hypoaspsis mites , or applications of Dimiln (diflubenzuron) or Citation (cyromazine).
If already established, rotated applications of Senator and Medallion may limit Black Root Rot, but are unlikely to cure it.
Lastly, Million Bells are highly attractive to aphids. With baskets hung up in the greenhouse, they can be “out of sight, out of mind”, but regular monitoring is needed to prevent large aphid outbreaks. Place sticky cards directly in baskets, and routinely check plant material for aphid cast skins and honeydew.
Once aphids are detected (and they will be!), applications of Beleaf (flonicamid), Enstar (kinoprene) or Endeavor (pymetrozine) will usually take care of them. However, be aware that all of these insecticides take around 4-5 days to start causing aphid death.
That’s right! As of today, flower growers have 2 new weapons against fungal diseases at their disposal. Heritage MAXX (azoxystrobin) and Medallion (fludioxonil) are now registered for use in outdoor and greenhouse ornamentals.
Heritage (a Group 11 fungicide) is asystemic fungicide, and is appropriate for control of Pythium, Grey mould (aka Botrytis blight)and Rhizoctonia.It can also be used for foliar diseases such as Powdery Mildew, Downy mildew, Rust, Anthracnose and Alternaria Leaf Spots. You can find the new label here: HeritageLABEL2016.
Medallion (a Group 12 fungicide)is a contact fungicide, and is appropriate for control of root rots such as Fusarium, Rhizoctonia, and Black Root Rot (Thielaviopsis) when applied as a drench. It can be applied foliarly for Grey Mould, Anthracnose Leaf Spot and Rhizoctonia Stem Rot. MedallionLABEL2016.
Both are broad-spectrum fungicides that can be used curatively or prophylactically.
As with any chemical control product, make sure to read and follow the label carefully prior to use.
(Also, 1000 points each to the team that helped push these label expansions forward:Cary Gates, Flowers Canada; Jim Chaput, OMAFRA; Jennifer Llewellyn, OMAFRA and Graeme Murphy, formerly of OMAFRA).
Check out this flyer for details on my “Intro to IPM” workshop on Feb 25th. The workshop will cover identification of common pests (insects AND diseases!), review of IPM basics, and optimizing IPM strategies in greenhouse floriculture crops.
This is a great workshop for new greenhouse employees, first year scouts, or as a refresher.
A more advanced workshop will be offered in the summer on integration of biocontrol and IPM for key pests (date and exact topic TBD, so check back!).
In anticipation of Monstanto BioAg’s decision regarding re-sourcing Met52, Canadian distributor Plant Products stocked their shelves.
Plant Products currently holds over 1000 units of the popular Met 52 EC (emulsifiable concentrate) product.This should be enough to bridge any gap in supply from Monstanto. Met 52 EC has a shelf life of up to 1 year if stored properly.
Met 52 EC is registered for use on strawberries, lettuce, cucumber, zucchini and fruiting vegetables (pepper, tomato, eggplant) in Canadian greenhouses.
Unfortunately, floriculture growers are still without a Metarhizium-based insecticide for now. Plant Products confirms that Met 52 Granular Insecticide – the only formulation registered on ornamentals –will NOT be available in 2016. We will update you on any potential availability in the future.
Meanwhile, stakeholders are working with the registrant to explore the possibility that Met52 EC could be registered for greenhouse ornamental use via the minor use program. However, as this previous blog post explains, even label expansions for currently registered products take time. However, biopesticides like Met52 are often expedited.
After several months of uncertainty, Monsanto BioAg will continue to offer Met 52 bioinsecticide. However, as new sources of inputs are being pursued, the product will not be available between February and October 2016.
This affects both the EC and Granular formulations.
Met 52 (which contains the beneficial fungus Metarhizium anisopliae) is one of three fungal-based bio-insecticides we have registered in Canada for greenhouse pests such as thrips and whitefly.
During this gap period, growers using Met 52 in their IPM programs may want to switch to products containing the fungus Beauveria bassiana (e.g.BotaniGard 22WP, BioCeres WP). Beauveria also has activity against thrips and whitefly. For more details on best use of Beauveria-based products, see this page on the GreehouseIPM.org website.