Impact of Extreme Heat on Apple Quality and Harvest in Basso Sarca

The cooked apples are served at the end of lunch: after removing the core and replacing it with a pat of butter, a teaspoon of sugar, and a pinch of cinnamon, they represent the traditional finish to a meal.

However, if the apples are cooked by the sun while still attached to the tree, it indicates that the temperature was too high for a prolonged period of days: and the apple is to be discarded.

Climatic Conditions and Effects on Fruit

That around mid-August, temperatures reach 24-25 degrees Celsius even at night for a few days is within the normal range.

This year, during the ten days up to August 25th, the intense heat lasted continuously, with daytime temperatures around 34 degrees Celsius.

Furthermore, in August, farmers perform a second pruning to lighten the tree of leaves and allow the fruits to develop color and flavor.

This year, on the side of the apple exposed directly to the sun, the extreme heat causes a modification in the cellular walls just beneath the skin: externally, a darker spot appears, similar to a sunburn.

If the damage is limited to the outside, the fruit is still marketable: instead of first category, it falls into the second category, with a significantly lower price, but still allowing the grower to recover some costs.

However, when the damage extends beyond the spot and affects the fruit’s flesh, which becomes soft and stained, the apple is truly inedible and must be discarded.

Harvesting and Quality of Apples

Annually, around 250,000 quintals of apples are harvested in the Basso Sarca area.

At present, the harvesting of stark delicious apples, which are red in color, is in full swing.

Once finished with those, the focus will shift to the golden yellow apples: these two varieties are the most common in the area.

The Cooperativa della valle dei Laghi estimates about 10% of the fruit is stained but still marketable, while no more than 2-3% is discarded.

The director of the Cooperativa contadini is more cautious: he believes that the phenomenon is not significantly more widespread than in previous years and postpones a thorough assessment until the end of harvest.

“There are too many variables,” he states. “The position of the tree, the position of the fruit on the tree, make it hard to provide precise data.”

The high temperatures of the latter half of August affected not only the apples but also the classic plum: many fruits remained smaller than usual and displayed wrinkles around the stem.