The march of the mealybugs (and scales)

We have been monitoring for movement of crawlers of mealybugs and scales in commercial vineyards in Niagara with a history of mealybug and scale since early April of 2019.

The crew started finding crawlers on double sided tape wrapped around the heads and canes of vines 2 weeks ago but crawlers were few and far between. 

This week the crew started looking on canes, especially under the bark that peels up when canes are bent to be tied. They found LOTS of crawlers. 

Spring sprays for mealybugs and scales

These insects are easily detected on canes (with a hand lens if you need reading glasses) so head out the vineyard and see if they are active. The next few days would be the optimum time to apply a spray to try to kill off these exposed crawlers and reduce the mealybug population.  Sprays are more effective on younger instars. Once mealybugs return to the trunk under the bark to lay eggs, only Movento will reach them and you’ll have missed this first generation of insects because Movento won’t move down into the trunk and affect the second generation until after bloom.   

To ensure penetration of the spray under those flaps of bark, use a high volume of water. This would be an excellent time to use a recycling sprayer.  Products registered for control of mealybug include Vegol Crop Oil (20 L/1000 L water), malathion (880 mL/1000 L water), Kopa or Opal insecticidal soaps (10 L/1000 L water) and Clutch (140-210 g/ha).  These products will also control scale crawlers.

This timing has not been recommended in the past in Ontario (or in Publication 360, but it will be in future editions) because we did not have a good feeling for the timing for this early season treatment, but the time is NOW!