Actually the plant looks like the nutrition/water regime might be off rather than the foliage being eaten.  When Plants don't get enough or too much water, too much of a nutrient, fertilizer, etc. the edges of the leaves can dry out or die.  After time the dead areas are brittle and with wind/movement can break off looking like they were eaten.  You might do a soil test to check your pH and make sure the plants are watered thoroughly once a week with 1" of irrigation or rain and that the soil drains well so it doesn't drown the roots.