Two days ago, I noticed a mass of small, hairy caterpillars on a single leaflet of a pecan leaf.
walnut caterpillars, Datana integerimma, a well known pest of walnuts and pecan trees.
Meanwhile, the third group of caterpillars had attracted some attention. Some lethal attention, actually. Two wheel bugs had positioned themselves between the caterpillars and the healthy leaves of the twig they they were on.
Anyway, according to the information sites that I found on the web, I probably should get rid of these caterpillars while I can. This is probably the first generation...and there is usually a second generation too. The caterpillars usually cause their most extensive damage in the last instar before pupating; then the second generation will cause more damage, as it's likely to be larger.
The wheel bugs will presumably take care of the one cluster that they are systemically guarding and eating. That leaves the other two clusters. If I destroy them by plucking the leaves and drowning the caterpillars in soapy water, I may be able to keep further damage from occurring. But then there is no further chance for other predator or parasite numbers to increase. According to the Forest Service information sheet that I linked to above, there are at least 13 parasites known to attack these caterpillars, as well as several predators (such as the wheel bug and certain spiders), and viruses and other diseases.
For now, I think I will let nature take her course and just observe. Reality "television" at its most real!