Bayer’s $66 billion acquisition of Monsanto will likely not get past European regulators if they stop Dow Chemical and DuPont from merging, a dealmaker close to the situation said.

Dow and DuPont said this week it would take three months longer than their previous guidance to complete their tie-up, as they work through regulatory issues. They expect the deal to close by the end of June.

The Post reported exclusively on Jan. 15 that the merger of equals was experiencing serious European regulator pushback.

A giant wave of consolidation is engulfing five of the six largest players in the seed and agrochemical business, with Dow and DuPont’s regulatory review the furthest along.

The European Union’s biggest concern is that a merger will lead to reducing spending on insecticide research and thus smaller global yields, sources said. The EU also wants the combined company to divest some assets, they added.

On the plus side, Dow and DuPont stand to increase market share as more weeds become resistant to rival Monsanto’s category-leading Roundup products, a chemicals analyst said.

Bayer and Monsanto’s chief executives met with President Trump earlier this month and committed to increasing their combined US operations, which could decrease their employment in Europe, a source said.

Monsanto, run by CEO Hugh Grant, declined to comment.