Have grown kidney beans and climbing French beans which were a the top of the sticks doing well, also beetroot. within 2 days they have yellowed at the bottom and are now wilting. Cant find any insects nor ants when I disturb the soil. An awful lot of ants in the garden this year. Have put down traps in the veg plot but they seem immune. Any ideas? Very distressed am going to lose all this years bean produce.