He added, "Don't waste any more of our time."
While Biden has spent the better part of the last month ratcheting up his critique of Trump over everything from his response to George Floyd's killing by police to his handling of the economy, the 15-minute speech today marked his sharpest remarks yet on the President's handling of the virus outbreak.
The presumptive Democratic presidential nominee attacked Trump for the high rate of US deaths and charged that the economy is "still sputtering."
With "no clear guidance" from the federal government on how businesses should respond, Biden warned the economic outlook could get worse.
"We may lose some of the progress we've begun to make all because he's lost interest," Biden said.
Earlier today, at a soul food restaurant and bar in the Philadelphia suburbs, Biden met a handful of small-business owners for a socially distanced listening session to hear how the coronavirus pandemic has affected their businesses.
Sitting 2m apart from each other around tables outdoors, the local business owners expressed concerns over a lack of guidance from the federal government on reopening.
Scott Richardson, the owner of Occasionally Yours Cafe and catering company in Swarthmore, Pennsylvania, said he cut his workforce from 12 employees to four amid the pandemic.
He told Biden that he voted for Trump in 2016, but now he says the president is more interested "in day trading" than long-range planning to combat the coronavirus.
Biden, in a hint of remarks to come, told the group that "no one" in the Trump Administration "is taking responsibility" during the outbreak.
Last week, Biden was in Philadelphia to unveil a multifaceted plan he said would gradually reopen the economy, increasing growth while not putting business owners or consumers at unnecessary risk.
The former Vice-President promised that, if elected, he would guarantee testing for the virus and protective equipment to guard against its spread for people called back to work.
He also wants to use federal funds to ensure paid leave for anyone who falls ill, or cares for those who do, and to create a national contact tracing workforce or "job corps" of at least 100,000 to call people who test positive, track down their contacts and get them into quarantine.
Biden further proposed a "safe shopper" programme meant to make returning consumers less wary of getting sick.
His campaign hasn't said how much all that would cost, however, and Biden himself even made a joking reference to being a "big-spending Democrat." But he countered, "If we don't do this, we're going to be in deep, deep, deeper trouble economically."
The former Vice-President says Trump has repeatedly prioritised the economy and the standing of financial markets over the nation's health, saying, "Trump has basically had a one-point plan: Open businesses."
Trump's re-election campaign argues that the Republican president issued "science-based" guidelines to jump-start the economy weeks before Biden did.
Since ending two-plus months of exclusively virtual campaigning from home amid the pandemic on Memorial Day, Biden has attended gatherings with small crowds a couple of times a week.
He's never strayed far from home, though, except when he headed to Houston to meet with the family of George Floyd — whose death in police custody in Minnesota has sparked weeks of protests around the country on racial inequities.
Still, Pennsylvania is important because exceedingly narrow victories in the state as well as in Michigan and Wisconsin clinched the White House for Trump in 2016.
Biden's campaign has pledged to resume a normal campaign schedule that will take him around the country, but not before authorities and health officials deem it safe. Trump will be in Tulsa, Oklahoma, for his first major campaign rally in months this weekend — though he doesn't take questions from voters at such events.
Tim Murtaugh, a spokesman for the President's re-election campaign, slammed Biden for preferring "campaigning from the comfort of his basement" rather than "travelling the country meeting voters and making the case for his candidacy."
"These events have been either tightly controlled or covered by press in a pool arrangement," Murtaugh wrote of the former Vice-President's recent stops.
"At what point will Biden subject himself to the scrutiny American voters deserve when considering the next President of the United States?"
- AP
