We received confirmation from Marie Rojas in Darnestown and Steve Dubik in Frederick that they are finding dogwood and styrax that are actively being attacked by ambrosia beetles this week.
On Tuesday, late in the day, I examined alcohol trap samples from Union Bridge (Carroll County) and Gaithersburg (Montgomery County) and both trapping sites have Xylosandrus germanus in fairly large numbers in their trap catches.
One note–As you apply the pyrethroids to the trunk of trees to be protected, try to use low pressure and do not use an air blast sprayer that slops the pesticide all over the nursery or landscape. The pyrethroids are very hard on predators and parasites. So, the objective is to direct the spray just to the trunk and main branches to minimize impact on beneficials.