My yard is being eaten by insects. I don't want to make a mistake identifying them. Can I put Diazanon on the surface for a day and water it the next day? Won't that kill whatever is the problem?
Homeowners should never treat a lawn or yard without identifying the source of the problem or what the pest is. There could be multiple issues all with differing causations.
There are several options available:
Provide 3 good photos of your lawn and the problem. Include as detailed description of the problem as possible.
Take a sufficient lawn sample (6"x6"x6") to the Arapahoe County Extension office for diagnostics. There is a small fee for diagnostics.
Use the Lawn Check service. The Horticulture Agent can make a site visit and give an accurate assessment. There is a $75 fee for this service and can be scheduled at this link: https://arapahoe.extension.colostate.edu/horticulture/lawn-care/lawn-check-diagnostic-services/
Based on your question history, it appears that you have been previously informed that Diazinon has been banned from residential use since 2005 and should not be used.