This is an interesting result. It rudely informs us that the tool kit available to plants is massive and kept safely in reserve against need. This is surely how our own immune system actually works.
It also indicates serious communication ability. This is no automaton at all.
Recall the information that ayahuasca is deemed the mother plant of Shamanism. This means that a prepared shaman takes the brew and in a trance is shown what plants can be used to resolve a sickness. It is not even slightly empirical at all. It becomes plausible that the spirit body is able to link into the plant networks in order to query this network for solutions. I would like to see it applied to Chinese medicine.
However, plants responded quicker and more strongly when fed on by the beet armyworm compared to the cabbage butterfly caterpillar indicating again that plants can tell the two insects apart. A sister study, led by Erin Rehrig, a doctoral student at the University of Missouri at the time of publication, showed that attacks by both caterpillars and beet armyworms increased plant hormones that trigger defense responses.