|in 2 days from having grass it went to no grass and lots of hard weeds. looked like it had beenn cut. there are thousands of caterpilars on ground. help|
|You didn't describe them so I'm not sure what the caterpillars are. The most likely culprits are sod webworms. These are the larvae of small moths and they can be a problem on lawns. Several insecticides are registered for control of sod webworms; Bayer Advanced Power Force Multi-Insect Killer, Grubex, or Bacillus thuringiensis
(Dipel 2X). Be sure to apply according to label directions. Once the pests are controlled you'll want to rake out the dead areas and reseed them. Best wishes with your lawn!