IT is an extremely busy weekend on the field with the start of senior cup campaigns in three provinces. In addition, the final series of matches in the Youths interprovincial Championship will determine who wins that title. Munster who have beaten both Ulster and Connacht, need only a draw against Leinster at Merrion Road today to take the championship. Connacht take on Ulster at Ravenhill in the second match.

The Pilkington Cup tie between Leeds and London Irish at Leeds will be watched by Ireland coach Murray Kidd and selector Joe Miles. They will get a chance to see outside half David Humphreys make his competitive debut for London Irish, and the performances of such as Conor O'Shea, Barry Walsh and centre Robert Henderson, will be noted with interest.

Selector Donal Lenihan will be at the friendly match between Dolphin and Shannon in Cork today to assess the form of international flanker Eddie Halvey in his comeback match after his long lay off due to a stomach/groin muscle injury.

Ireland manager Pat Whelan and his fellow Ireland selector Frank Sowman will be at Templeville Road this afternoon to see the holders, St Mary's College, open their defence of the Leinster Senior Cup against Lansdowne in what looks the match of the round. The performance of St Mary's number eight Victor Costello will be watched with special interest as they contemplate the composition of the side to meet France.

Having watched that match, Whelan and Sowman will then travel to Anglesea Road to see Old Belvedere play DLSP in the cup. While all other first round ties have a 2.0 pm kick off in case extra time is needed, the match at Anglesea Road starts at 4.0 pm. Two other ties today are the meeting of old Wesley, and Clontarf at Donnybrook and Monkstown and junior qualifiers Seapoint at Sydney Parade.

There are four Leinster ties tomorrow, last season's beaten finalists, Greystones, will be at home to Bective Rangers. Terenure College take on UCD. Skerries will have home advantage against Trinity and Blackrock College meet Wanderers at Stradbrook.

Blackrock have been hit by an injury crisis. They will be without their international outside half Alan McGowan, who is recovering from pneumonia. He is replaced by his brother John. Niall Woods (hamstring), Dean Oswald (medial knee ligament) and Fergal O'Beirne (abroad) are also ruled out. Rory Kearns takes over on the wing from Woods, Danny Cassey moves from flank to number eight and American Greg Bartlett is named on the flank.

Munster Cup holders Garryowen also have severe injury problems as they prepare to meet junior qualifiers Clanwilliam in the cup tomorrow. Already without the services for a protracted period of Philip Danaher, Keith Wood and Richard Costello - Costello will not play again this season because of a knee ligament injury second row Mick Coughlan has a broken band and Paddy O'Grady has a knee injury. Scrum half Stephen McIvor is under treatment for knee and shoulder injuries, but it is hoped both he and O'Grady will be fit to play.

Old Crescent take on Highfield in the cup today and Sunday's Well meet Bohemians. Interprovincial second row Eoin O'Sullivan will be an absentee for Old Crescent. But an interesting selection on the Highfield side is Cork All Ireland footballer Shea Fahy, who is also an accomplished rugby player. Emmet O'Callaghan and Denis McCarthy, both having returned from abroad, are also in the Highfield side.

Sunday's Well will be without their captain and Munster interprovincial back row forward Jim Cutriss. Stephen Rose will deputise.

In addition to the Garryowen Clanwilliam match tomorrow, UCC meet Waterpark in the cup.

UCC will be without their captain, Tim O'Connell, and Waterpark will be minus the services of their international number eight. Ben Cronin, who is abroad on business. But Waterpark will have three experienced campaigners in their side.

Carl Phelan, Brendan Moran and Gus Walsh all played for the club in the Munster Senior Cup final 12 years ago.

In Ulster, Dungannon set out on the cup trail with their sights set on winning the trophy for the fourth successive year, a feat not achieved by any club since Queen's University 1950.

Dungannon visit Carrickfergus, who have a former Dungannon stalwart in their side, Paul Archer. Paddy Johns and Jeremy Davidson return to the Dungannon side alter their long absence due to representative commitments.

The meeting of Portadown and Malone at Chambers Park brings Malone into opposition with a man who served the club so well for so long, former international hooker John McDonald. He is in a Portadown side unbeaten this season. They have a 100 per cent record in the fourth division of the All Ireland League and also in the Ulster Senior League in which they beat Malone, admittedly depleted, comprehensively.

In the other counties, Derry are at home to Queen's University.

CIYMS to Instonians, Collegians to Armagh. Enniskillen to Ards. Bangor to NIFC and Omagh to first division Ballymena.