Poor pollination drives sharp drop in pear, apple and cherry in Río Negro and Neuquén

Fruit growers in Río Negro and Neuquén (Argentina) are reporting production losses of 30% to 50% this season, and new analysis from INTA points to one main cause: pollination problems.

During spring 2025, orchards across Alto Valle, Valle Medio and Río Colorado saw unusual levels of fruit drop in apples, pears and cherries. While growers offered different explanations, the National Institute of Agricultural Technology (INTA) says three issues are behind the decline: poor pollination, low boron levels, and orchards with excessive vegetative growth.

According to an INTA agrometeorological report, frost was not the main factor. Instead, the weather during bloom — especially in September — limited bee activity. The region had 18 days where bees could not fly for more than six hours, and on seven of those days, conditions were too poor for pollination. Low temperatures, wind and rainfall reduced bee flights, and mismatched flowering between main varieties and their pollinizers made the problem worse. For example, Granny Smith bloomed later than Red Delicious, lowering the chance of effective fruit set.

Low temperatures also slow pollen-tube growth, meaning fertilisation takes longer or fails. INTA notes that at 10°C, the pollen tube needs twice as much time to reach the ovary as it would at 17–22°C.

Other factors added pressure. Boron deficiency — especially common in Packham’s Triumph pears — affects pollen germination, so INTA recommends boron applications after harvest or at early bloom. Meanwhile, orchards with too much vigour, often due to short pruning or excess nitrogen, tend to drop more fruit because shoots and flowers compete for energy.

In short, INTA concludes that the lower yields this year are the result of several combined factors: weak pollination caused by bad weather and poor bloom synchrony, possible nutrient shortages, and imbalanced orchard management.

source: frutasdechile.cl

photo: wikipedia.org