Law enforcement sources in L.A. tell TMZ ... a major uptick in these bizarre calls started after California's Gov. Newsom issued the "stay at home" order last week -- an order many are taking VERY seriously.

For instance ... we're told people have called to report neighbors for exercising in their yards or simply eating outside. Others have ratted on their neighbors or nearby businesses because gardeners and landscapers are still showing up to work on their properties.

Fact is, those activities aren't illegal, but some L.A. residents clearly frown upon them. Landscaping is considered an "essential activity" in certain cases if it contributes to sanitation needs, but not if it's just to trim a homeowner's hedges.

Other snitching calls are coming from social distancing warriors, so to speak. We mean folks reporting people for playing basketball at outdoor parks, gathering in large groups outside or companies with more than 10 employees still going into the office.

Then, there's just COVID-19 paranoia calls to report neighbors coughing. Even more extreme ... we're told police even got a call to check out 2 people sitting on a bus bench who were coughing.

Point is, while many new restrictions were put in place this week to encourage Los Angelenos to stop gathering at beaches, parks and hiking trails -- the majority of residents are taking the quarantine seriously.

Maybe too much, because we're told cops are also getting many calls from people asking for a permit to go outside.