public function worklist()
{

    $worklist = TableRegistry::get('Fincas');
    $query = $worklist
        ->find()
        ->select(['id', 'prov', 'municipio', 'paraje', 'poligono', 'parcela', 'f_ult_poda' , 'f_ult_recog' ]);

    foreach ($query as $worklist) {
          if ( $worklist->f_ult_poda > $worklist->f_ult_recog )
              debug($worklist);  //it works fine
      }

    $this->set('finca', $this->$query); //I have tried also $this->$worklist

}

<?php debug($finca);?>