The EU's new wheat export subsidy programme has failed to support EU wheat prices, it said.
Subsidy awards of up to six euros ($7.84) a tonne have until now "simply be used for previously completed business", the report said.
"Without significantly higher refunds (subsidies), further volumes cannot be sold on world markets," it said.
Feed barley prices have risen recently because of separate EU export subsidies, but were again on the defensive because of the small tonnages actually awarded subsidies by Brussels recently, it said.
Generally high feed barley prices meant animal feed makers were using barley only when absolutely necessary.
EU maize prices were low and not expected to recover in coming weeks, partly because of EU approval for imports from third countries at reduced customs levies into Spain and Portugal.