If we can travel through wormholes (which is incredibly unlikely for some really serious reasons) or just get around the limitation of travel at the speed of light (as we do with phase engines) then there is room to consider using neutrino's as weapons.
Here's some facts (Wikipedia) that can suggest some theory for this (but trust me, we're pure SciFi going from here to that)...
Neutrinos can interact with a nucleus, changing it to another nucleus. This process is used in radiochemical neutrino detectors. In this case, the energy levels and spin states within the target nucleus have to be taken into account to estimate the probability for an interaction. In general the interaction probability increases with the number of neutrons and protons within a nucleus.
Alteration of nuclear decay rate
A Russian study suggests that the decay rate of radioactive isotopes is not constant as is commonly believed, and a recent study also finds this, and says it appears to be affected by the rate of neutrinos emitted by the Sun.
Very much like neutrons do in nuclear reactors, neutrinos can induce fission reactions within heavy nuclei. So far, this reaction has not been measured in a laboratory, but is predicted to happen within stars and supernovae. The process affects the abundance of isotopes seen in the universe. Neutrino fission of deuterium nuclei has been observed in the Sudbury Neutrino Observatory, which uses a heavy water detector.
These might work well too. Perhaps having a Ghostbusters style "Don't Merge the Streams" where a neutrino and antimatter neutrino beam are synchronized to converge inside a target and annihilate one another or initiate a nuclear reaction in the target mass--perhaps targeting antimatter containment for example.
Neutrinos would probably work best on very dense targets so armor could actually be a liability versus them.