Mangra of the vine

On 29 July 1853 the agronomist João de Andrade Corvo, who later became one of our most distinguished writers and statesmen, arrived in Funchal. He had been commissioned by the central Government to make a thorough study of the disease that had attacked the vineyards of this island and to propose the measures most likely to overcome the calamities then afflicting us.

Our vines had been attacked by Oidium Tuckeri, to which the people had given the name mangra (powdery mildew of the vine, oidium). The disease had appeared in Europe only a few years earlier, and it seems that its presence was first recorded in a garden in England in 1845. It was suspected that its appearance in Madeira dated from 1851, but it was in 1852 that the disease spread and began to cause its terrible damage. In February 1851 a French subject visited Funchal, and among the collection of plants he sold in this city were some varieties of vine, gathered in France in localities already invaded by the disease. A distinguished agronomist supposes that this was the cause of the invasion of Oidium Tuckeri in this archipelago.

To give an approximate idea of the violence of the disease and its disastrous consequences, it is enough to say that average wine production in the years 1849, 1850 and 1851 was fifty thousand hectolitres. In 1852, the first year of the general invasion of the mangra, it was eight thousand; in 1853 it fell to three thousand, and in 1854 to a mere six hundred hectolitres. The difference between 1851 and 1854 is roughly 80 to 1.

The economic crisis this caused throughout the district was enormous. The island was not prosperous at the time, since its only profitable crop was the vine. Sugar cane was grown on a small scale. Bananas and other fruit, and vegetables too, were not produced in sufficient quantity for export. The butter and embroidery industries existed only in a rudimentary state, and reached the development they have here today only later.

The crisis that followed the disease of the vineyards was among the most serious ever to have struck this archipelago. One of its consequences was emigration, which in some years reached alarming proportions. Famine settled among us, with all its train of horrors.

To relieve so many ills, the central Government ordered the construction and repair of various roads, thus employing some hundreds of hands who had no work. By royal decree (alvará) of 22 November 1852, the civil governor of the district appointed a large committee charged with promoting a subscription and the collection of donations in several foreign countries. It went on to distribute relief to the value of thirty-seven contos (1 conto = 1,000,000 réis, from 1911 1,000 escudos), and for six months employed about three hundred men each day on the road linking Funchal with the town (vila) of Câmara de Lobos.

João de Andrade Corvo stayed two months in Madeira, and in 1854 published an interesting report on the studies he had carried out in this archipelago, a work that still deserves to be read by scholars today.

The mangra still exists in the vineyards of the archipelago, and sulphur has long been used to combat it. It forms patches, white at first and later greyish, which appear on the leaves, shoots and bunches of the vine, and are produced by the mycelium and spores (conidia) of the fungus. The mycelium lives on the surface of the green organs of the vine and sends small suckers into them, through which it feeds.