The House is unlikely to pass a 1990 farm bill until the end of June at the earliest, a ranking member of the Agriculture Committee said Friday.

''We're slipping day by day," Rep. Charles Stenholm, D-Texas, told reporters in response to questions about the likelihood Congress will fail to send a 5-year farm bill to President Bush by the summer recess scheduled to start Aug. 6.Rep. Stenholm said the Agriculture Committee will finish its work on the farm bill Tuesday after hammering out final details of conservation policy and getting the overall costs of the bill in line with current budget requirements.

He added that the week of June 25 has been set aside for floor debate, but that timetable may not be met due to a logjam of appropriations bills that is gathering on the House floor.

Rep. Stenholm said the bill as written by the committee is about $2.6 billion over budget requirements over its 5-year life and about $340 million over for fiscal 1991.

He said some bookkeeping changes will achieve some of the savings but said the Targeted Export Assistance program would be capped at $200 millions, down from the current $325 million in the bill.

But completion of the 1990 farm bill faces hurdles way beyond the House committee and floor debate.

Senate Agriculture Committee members are in a partisan deadlock over target price and loan rate levels. The committee will attempt to begin writing the major commodity part of the bill Tuesday.

Rep. Stenholm said House committee completion of the farm bill may jolt the Senate Agriculture Committee into action. "Not many senators will want to go home for the Fourth of July without doing anything on the farm bill," he said.

White House and congressional budget experts have only just begun their discussions to bring federal deficits under control. Whatever formula they devise later this year will control the overall cost and makeup of the farm bill.

If the budget talks succeed, Rep. Stenholm said farm bill costs would have to be cut by $800 million to $1.5 billion. If the talks fail and the Gramm-Rudman law's automatic across-the-board cuts go into effect, farm programs could be slashed by as much as 30 percent, he said.

Once the farm bill reaches the House floor, Rep. Stenholm said it is likely to be the target of amendments to impose a farmer income means test for qualifying for federal subsidy payments, as well as amendments to change current sugar and peanut programs.