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.
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.
What’s the first thing you do with your shipments of predatory mites, parasitoids and predators when you receive them? You probably check to see if these natural enemiesare alive before you put them out in the crop.
Now Albert Grimm (Jeffries Greenhouses) and I have come up with a way to check if many of your microbial products are still viable, too.
We’re still in the process of testing these methods for all microbial products, so please consider this preliminary. Right now, we know this works for Beauveria and Metarhizium-based products only (e.g. BotaniGard, BioCeres and Met52). I’m hoping to put the methods up for more products in December.
Distilled (sterile) water. Unopened bottled water will do in a pinch. Do NOT use tap water.
Step 1: Disinfect the water cup and the measuring spoon with rubbing alcohol. Wipe dry with paper towels. Step 2: In one plastic cup, add a small amount of sterile water (a few mL is fine). Keep for Step 4 to act as a control. Step 3. Take a second cup to mix up your product in. Add 200 mL of sterile water. Then add approx. 1/16th of a teaspoon (0.3ml) of product (Beauveria or Metarhizium). To measure, fill the smallest baking measuring spoon (1/8th of a teaspoon) about half way. Stir well. This will give an approximate concentration of 1 g/L, which is similar to recommended rates of these products. Step 4: Take a disposable pipette and fill with sterile water. (Make sure to re-seal your bag of pipettes so they stay clean and sterile). Grab a single Petrifilm and peel back the thin, clear cover on top. Carefully squeeze the pipette to form a line of water across the surface of the Petri film. Step 5. Repeat Step 4 on the same Petrifilm using your product in solution. You can use the same disposable pipette (since it only had sterile water in it previously).
Step 6. Gently drop the plastic cover back over the Petrifilm. Write directly on the plastic cover with a sharpie to indicate the position of your “control” water line and your “product” water line (see Fig 3). Store the film between 20-25 °C in a dark location.
Step 7: After a minimum of 16 h (the time it takes for Beauveria spores to germinate), check your Petrifilm. The sterile water line should be blank. The Beauveria and Metarhizium lines should be light blue -the film has a dye in it that reacts to fungi (Fig. 3). Note that this dye reacts to ANY fungi or yeast. Thus, you CANNOT use it to diagnose what fungus is growing. This is why the sterile water control is so important – you want to be sure the reaction is from your microbial product, and not from random fungal spores in your water.
With the growers still tentative in their use of microbial-based products, this viability test may give growers some piece of mind. It will be particularly useful for product that’s been shipped in hot summer months, or in the dead of winter, as some products are sensitive to extreme temperatures. It can also be used to testproduct that has beensitting in storage for long periods.
Note that this is a simple live/dead test. These methods do not quantify how much of the product is still viable. That’s something Dr. Anissa Poleatewich (Vineland) and I are working on, as we think it would be useful to know if your product is decreasing in efficacy over time. So, stay tuned for more information as we perfect our methods.