Here is the latest Iowa news from The Associated Press at 3:40 a.m. CDT

DAVENPORT, Iowa (AP) — President Donald Trump and former Vice President Joe Biden are unleashing the kind of verbal attacks that feel more appropriate for the final weeks before Election Day than a lazy summer day about 17 months before voters go to the polls. Biden says Trump is an “existential threat” to the nation. Trump suggests Biden is “weak mentally” and insists, “People don’t respect him.” Both men were campaigning in Iowa Tuesday, and Biden has one more event in the state Wednesday.

DES MOINES, Iowa (AP) — The U.S. Department of Agriculture has lowered its estimate of this year’s corn crop to the lowest in four years, saying wet weather has delayed planting and reduced acres planted and the expected per-acre yield. Production was cut in a monthly report released Tuesday by 1.4 billion bushels to 13.7 billion bushels, the lowest since 2015.

DES MOINES, Iowa (AP) — A study shows Iowa leads the nation in the amount of human and animal waste it produces. Christopher Jones is a scientist at the University of Iowa. The Des Moines Register reports that Jones’ study shows the state of 3.2 million people and total livestock population of nearly 110 million produces as much manure as a human population of 168 million. His study indicates pigs are responsible for driving the state to the top of the rankings.

NEBRASKA CITY, Neb. (AP) — A judge has ordered a mental evaluation for an Iowa man charged in the deaths of his former girlfriend’s parents in Nebraska. Sioux City, Iowa, station KTIV reports that the Nebraska judge on Monday ordered the evaluation for 36-year-old Brindar Jangir to determine whether he is mentally fit enough to stand trial. Jangir was arrested in March in the shotgun deaths of 56-year-old Randal Grimes and 51-year-old Annette Grimes in Douglas, Nebraska.

(Radio Iowa) — The upcoming three months will be a prime time to look for — and find — a new job in Iowa, according to the latest employment outlook survey from Manpower Group. Kathy Joblinske, Manpower’s executive vice president for Iowa, says the national outlook for third quarter is very good and Iowa’s outlook is even better.

“Among the employers that were surveyed, 31% plan to hire more employees July through September of this year,” Joblinske says. “That number is offset by 3% that plan to reduce the payroll and 64% of employers are expecting to maintain current staff levels.” Iowa’s net employment outlook for the approaching quarter is 28-percent, ahead of the national outlook of 21-percent and well ahead of Iowa’s outlook last quarter of 16-percent.

Hiring prospects are very promising in most industries, Joblinske says, and a few are far above the rest. “When we look at this time of year, construction is expected to be up and, sure enough, that is one of the top industries that are anticipated for growth,” Joblinske says, “as well as durable goods manufacturing, non-durable goods manufacturing and then transportation and utilities.” Only the information technology category looks to be falling, slightly.

“They are forecasting some decreases in information, although there’s still a lot of IT jobs available,” Joblinske says. “There’s a lot of job opportunity out there and there are more jobs available than there are job seekers at this point.” There are double-digit outlooks in all 50 states for the quarter ahead, and Joblinske says it’s the strongest outlook in 13 years.

NEBRASKA CITY, Neb. (AP) — A judge has ordered a mental evaluation for an Iowa man charged in the deaths of his former girlfriend’s parents in Nebraska. Sioux City, Iowa, station KTIV reports that the Nebraska judge on Monday ordered the evaluation for 36-year-old Brindar Jangir to determine whether he is mentally fit enough to stand trial.

Jangir was arrested in March near San Diego as he tried to re-enter the United States from Mexico. Jangir is charged with two counts of first-degree murder in connection with the March 23 shotgun deaths in Douglas, Nebraska, of 56-year-old Randal Grimes and 51-year-old Annette Grimes.

The affidavit says Randal and Annette Grimes were the parents of a woman Jangir was living with in Sioux City, Iowa, until she moved out March 12. The affidavit says she told officers Jangir threatened to kill her and her parents if she ever left him.

MOUNT PLEASANT, Iowa (AP) — President Donald Trump and Democrat Joe Biden spent Tuesday trading insults — sometimes almost simultaneously— as they stumped across Iowa in split-screen moments that could preview a ferocious fight ahead if the two face off for the presidency next year.

Biden’s name recognition and a sense among Democrats that he could beat Trump has helped him climb to the top of his party’s crowded presidential field. But Trump said Biden only gained in the polls because he went on the offensive against the president himself, and he linked the former vice president to 2016 foe Hillary Clinton.

“People don’t respect him,” Trump said after touring a renewable energy facility in Council Bluffs. “Even the people that he’s running against, they’re saying: ‘Where is he? What happened?'”

With a dose of exaggeration, the president added: “He makes his stance in Iowa once every two weeks and then he mentions my name 74 times in one speech. I don’t know. That reminds me of Crooked Hillary. She did the same thing.”

At almost the same moment in Mount Pleasant, Biden noted the attention he has been getting from Trump. Biden’s appearances from earlier in the day were playing on TV screens when Air Force One landed in Iowa.

“I guess he’s really fascinated by me,” said Biden, who mentioned Trump by name about a dozen times during his first two events in Iowa. “I find it fascinating.” He started to say more but then stopped himself, quipping: “My mother would say: ‘Joey, focus. Don’t descend. Stay up.'”

Pressed later by reporters about his repeated assurances that he wouldn’t openly criticize Trump while campaigning, Biden said, “By not talking about him personally — talking about where I disagree with him on the issues, why he’s doing such damage to the country — that’s totally different than attacking his character or lack thereof.”

Still, the back-and-forth laid bare the rising political stakes for each man, even with the election about 17 months away. Trump has zeroed in on Biden as a potential threat to his reelection chances and is testing themes to beat him back. Biden, meanwhile, is campaigning as a front-runner, relishing the one-on-one fight with Trump while making sure he doesn’t ignore the demands of the Democratic primary.

“I’d rather run against Biden than anybody,” Trump told reporters on the White House lawn before flying to Iowa. “I think he’s the weakest mentally, and I like running against people that are weak mentally.”

Biden began the day in Ottumwa, the heart of Wapello County, a meat-packing and agricultural manufacturing center that Trump was the first Republican to carry since Dwight D. Eisenhower. It’s part of Biden’s dual track approach: campaigning for the caucuses while projecting himself as someone who can win in territory Trump snatched from Democrats in 2016, such as Michigan, Pennsylvania and Wisconsin.

There, the former vice president hit Trump on the economy — an issue the president often promotes as his chief strength in a time of low unemployment.

“I hope his presence here will be a clarifying event because Iowa farmers have been crushed by his tariffs toward China,” Biden said. “It’s really easy to be tough when someone else absorbs the pain, farmers and manufacturers.”

Biden added that Trump “backed off his threat of tariffs to Mexico basically because he realized he was likely to lose” in manufacturing states such as Michigan and Ohio. He broadly branded Trump “an existential threat to this country” and said his behavior is beneath the office of the presidency.

For Trump, the power of incumbency was on display in this state dominated by agriculture interests. As the president toured a plant that produces and sells the corn-based fuel additive ethanol, he signed an executive order to “promote agricultural biotechnology.” He said the measure would help farmers by speeding up the scientific review of their innovative products and help get them to market faster.

“I fought very hard for ethanol, but you proved me right,” Trump said, adding that he fought “for the American farmer like no president has fought before.”

But he then again mocked Biden.

“He was some place in Iowa today,” the president said, “and he said my name so many times that people couldn’t stand it.”