Previously, we showed that cabbage loopers (Trichoplusia ni Hübner) can evolve >20X resistance to the single (S) nucleocapsid nucleopolyhedrovirus (NPV) of Trichoplusia ni (TnSNPV). In this study, we investigate one potential cost that resistant cabbage loopers may incur, increased susceptibility to other mortality agents. Contrary to expectation, no such cost was observed with any of the six mortality agents tested. In fact, the LD₅₀ of selected larvae was always greater than that of control caterpillars for each agent tested. However, the differences were never significant for permethrin or Bacillus thuringiensis subsp kurstaki (Berliner). The differences in the LD₅₀ of control and selected T. ni for the wild-type multiple (M) nucleocapsid NPV of Autographa californica Speyer (AcMNPV, clone C6) and the recombinant AcMNPV (AcMNPV-AaIT) were small (≈2X) and significant in only one of three generations. Surprisingly, the highest level of cross-resistance was to the granuloviruses of Pieris rapae L. (4–5X; significant in two of three generations) and T. ni (20–30X; significant in three of three generations). This suggests that the infection pathway of TnSNPV may be more similar to TnGV than to that of AcMNPV.