Grubs and roots.
The veggies in the wagon garden, one of my raised beds (raised, but resting on the ground), did not produce well the last two years. I had noticed the heavy roots before, but I had attributed them (and the failed crops) to a mistake I had made in the composition of the soil and the fertilizer I used. No such. The roots come from an opportunistic tree, whose trunk is about fifteen feet from the bed.
I have had to work hard to empty the bed, which was a mess of tangled roots. This pile about one foot high and three feet in diameter is what's left:

As I screened the removed soil, I found grubs,

and evidence of the power of these roots trying to establish themselves, penetrating, even, some peach pits:

On the fun side of things, here is the apple of my yard: