|Why my squash plants die or rot at the soil after growing
to big very plants?
|Sounds like damage from squash vine borers. I have fought squash bugs in my gardens and here is what works for me. First, squash the bugs and their eggs. I tried going out every three days or so and squashing the bugs I found along with any of their eggs. Their amber-colored eggs are laid in clusters underneath the leaves, usually in the protected area between two leaf veins. If you are squeemish about squashing them, carry a can of kerosene or alchohol and drop them into that.
If you will set a board under the plants near the stem, you will find they like to congregate beneath it during the day. This makes them "sitting ducks"! A piece of aluminum foil laid around the stem like a mulch will also harbor them.
Second, I spray occasionally with a pyrethrin/rotenone product. This is an organic option with good "knock down power" on the bugs.