Those diseases which had been formerly found but not identified in detail, such as tobacco Blank death, Blackroot rot, Wild fire, Angular spot and root-knot nematode were studied more thoroughly.
Mr Obama's black supporters hope he will make good on promises to root out racism in the criminal-justice system and the workplace by enforcing existing laws more vigorously.
Dishes on offer on Wednesday will include a sunchoke confit with dehydrated grapefruit followed by smoked sturgeon and beef with wild mushrooms, celery root, black vinegar and coffee.