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July 25, 2013

Cold Temperatures Impacting Crops in Southern Brazil

A mass of polar air continues to sweep across southern Brazil bringing with it the coldest temperatures of the year and in many locations, record low temperatures. Widespread frosts and freezes are being experienced in all of southern Brazil and as far north as Mato Grosso do Sul, Sao Paulo, and Minas Gerais. New record lows were set in 15 cities in the state of Sao Paulo and snow was recorded in 87 municipalities, mostly in the state of Santa Catarina.

While the cold and snow is a novelty for the Brazilian tourists in the region, it may cause significant losses for horticultural and fruit producers as well as some losses for the winter grain crop such as wheat and barley.

The biggest impact will be on sensitive horticultural crops and fruit crops such as bananas. The coffee crop in northern Parana and southern Sao Paulo is also expected to suffer losses from the freezing temperatures. Coffee plants are very sensitive to cold temperatures and once a coffee plant is killed by freezing temperatures, it takes a number of years before replacement plants start to bear fruit. In order to avoid these periodic cold snaps, coffee production in Brazil has been moving northward over the last several decades.

Nearly all of Brazil's wheat is produced in the states of Parana and Rio Grande do Sul. Approximately 40% of the wheat in Parana is in the jointing stage and it might be impacted somewhat by the cold temperatures. Agronomists from the state Secretary of Agriculture estimate that the most advanced wheat may lose 5% of its yield potential. The wheat in Rio Grande do Sul is still in the vegetative stage and it should not suffer any losses.

The wheat plant is most sensitive to freezing temperatures during heading and flowering and fortunately none of the wheat in southern Brazil has reached that stage of development. If these cold temperatures are repeated at the end of August or early September when the wheat is starting to mature, the crop could be severely impacted. It generally takes seven to ten days after the freezing temperatures to determine the extent of damage on wheat.

Late July is usually the coldest time of the year in southern Brazil, but the cold temperatures this year has been more intense and more widespread than normal. Only the coastal areas seemed to have escaped the freezing temperatures.

One benefit from the colder temperatures is that it helps to control overwintering insect and diseases and reduces early pest pressures on subsequent crops.