In the place where I live, even nowadays, searching for black summer truffles, especially for the Tuber Aestivum Vittadini or “Scorzone”, is not seen as something serious or important. It is generally considered as a way to train the dog for the “more prestigious” Tuber Magnatum Pico or “Rapone”.
In fact, searching for truffles in these areas, is seen as an auxiliary source of profit, useful to integrate a bigger income, earned from working in the countryside. That is why there was not enough time for searching truffles from May to August in the past.
It was not (and it is still not) convenient to risk your dog’s safety for little money: considering that a kg of black summer truffles is worth less than 100 gr of fine white truffles, it is not worthwhile taking so many risks such as: a bite from a viper, a sudden heatstroke or the ingestion of grass seeds or wild oat that can be lethal for your dogs if not treated as an emergency.
Normally, this kind of search was practiced only to gain experience by young people with young dogs (it is so sad to say) that could possibly be sacrificed.