A B.t. application should protect foliage in the treated area if applied before there is obvious defoliation. Two weeks seems rather long between two applications of B.t. and 3 to 7 days is more usual. However, the applicator is probably well aware of local conditions and knows what he is doing. It is best if the whole infestation is treated, but your trees will be protected and your neighbour's may be defoliated. Ontario is the northern limit of the North American gypsy moth infestation and outbreaks are relatively short.
Some years there is heavy egg mortality in egg masses above the snow line.
There is normally only one year of severe defoliation before population collapse, but there are always exceptions and we would certainly not want to make a definitive prediction in your case. However, egg masses in your area are small and the prognosis is an imminent gypsy moth population collapse. Dr. John C. Cunningham Research Scientist Canadian Forest Service Sault Ste.