Neil Carter is chair of Ontario's Ministry of Agriculture, Food and Rural Affairs' MALB Working Group (Ontario).
For vineyards in unfortunate proximity to soybean fields, how can growers avoid or mitigate MALB damage?
Grizzly bears sometimes dig up overwintering aggregations of MALB to eat them.
Delayed harvesting can exacerbate MALB problems, he says, since, "The main determining factor is date of grape harvest in relation to soybean senescence.
The migration of MALB also seems to be associated with a few nights of cool temperatures (40[degrees]F), which must trigger the migration.
That gives us a good idea of the potential MALB population," Bordelon says.
None of our sources could predict if, when or why the next calamitous MALB invasion would take place, but with harvest time nearing, it's time to ramp up your vineyard monitoring program.
We recommend an application when MALB are first seen on berries, and a follow-up if necessary prior to harvest," Bordelon says, adding that there are also other effective treatments with short pre-harvest intervals.
Keep in mind that it is only late in the year, as the grapes approach harvest, that MALB are a problem," Carter says.
There are parasitoids (insects that parasitize other insects) of MALB, including some I identified a couple of years ago as Dinocampus coccinellae, which is a common small wasp parasitoid of other lady beetles," Carter says.
Small batches of hand-harvested grapes can be completely cleaned of MALB with these same tables," he suggests.
These results should assist in directing appropriate interventions in the vineyard/winery, and provide baseline targets for reducing MALB density to avoid development of LBT.