In the past few days, temperatures have dropped dramatically throughout Italy, reaching 5-6°C below zero in some areas. It was a disaster for fruit and vegetables, but what have been the effects on the Halyomorpha halys brown-marmorated stink bug ?
Anti-frost irrigation in a kiwi field in Modigliana (Ravenna).
“Temperatures well below zero may have created some problems for brown-marmorated stink bug – says Michele Preti, technical investigator of the ASTRA Test Center – but it is nothing compared to the damage that frost has caused to production. In theory, according to past experiences and data, the sudden changes in temperature caused by the cold weather can compromise the vitality of the wintering bugs that have came out their shelters, but not in a decisive way. In other words, we must not delude ourselves”.
The brown-marmorated stink bug has a reproduction dynamics such that, even if the cycle starts with fewer insects, at the end of the season there can be a very high number of specimens.
“The loss of production caused by the frost is a serious problem – says Preti – Damaged apricots, for example, are permanently lost, while the bug unfortunately will adapt to the situation and will multiply during the year”.
A farmer from the Ravenna area, whose orchards have been affected by the insect in recent years, says that “the brown-marmorated stink bug is like Coronavirus, smarter than we humans. I think that most of the insects have felt in advance the drop of temperature, which in any case has been gradual from Sunday 22 March onwards, and that therefore they took shelter. I know I will have to fight against the brown-marmorated stink bug this year as well”.