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As with commodity markets in energy and basic materials, the U.K. vote to abandon the European Union is taking a toll on agricultural commodities markets Friday morning. So far, at least, ag commodity prices seem to be reacting mostly to the strengthening dollar versus both the British pound and the euro.

Chicago soft red winter wheat futures fell 1.7% and Kansas City hard red winter wheat futures fell 1.9% on the surging dollar. London wheat futures, however, soared 3.7% due to the collapse in sterling which had touched a 30-year low of $1.32.

Before Thursday’s Brexit vote the biggest concern for U.S. crops was, as is often the case, the weather. A dry summer has sent corn prices down sharply, from around $4.40 a bushel earlier this month to around $3.88 just before noon on Friday. The U.K. vote added a little push, but corn settled at $3.92 on Thursday.

Soybeans traded down as well on Friday. The key development month for the crop is August, a month later than the key month for corn, meaning that weather is not yet a central concern for the crop. A strong dollar sent July futures down 1.5% and November soybean futures were down 1.4%.

Among the major companies in the ag sector, Germany-based BASF SE and Bayer AG took the biggest hits, trading down 6.8% and 5.4%, respectively, at last look. Bayer’s tumble helped drag shares of Monsanto Co. (NYSE: MON) down about 3.5%, and both The Dow Chemical Co. (NYSE: DOW) and E.I. du Pont de Nemours and Co. (NYSE: DD) traded down more than 3%.

Deere & Co. (NYSE: DE) traded down about 2.6% shortly before noon, and heavy equipment maker Caterpillar Inc. (NYSE: CAT) traded down about 5.3%.

Sentiment appears to be that companies supply ag-related products are likely to do worse than just matching the currency exchange effects brought on by the weaker British pound.

The S&P 500 traded down about 2.7% and the DJIA traded down about 2.6% at the same time.