41. Only the discovery of phylloxera-resistant rootstocks enabled the wine business to survive. 42. Carrizo is becoming a popular rootstock for citrus, 43. He grafted merlot and sauvignon blanc and chardonnay vines on to the old rootstocks . 44. Other small-fruited species are frequently used as rootstocks for the cultivated forms. 45. Note that nearly all the apple rootstocks in the industry are now virus free. 46. Another desirable characteristic of rootstocks is environmental adaptability. 47. The Mark rootstock was such a stock and has now fallen mostly into disfavor. 48. Some of these hazards can be managed with integrated pest management and rootstock selection. 49. The leaves, often densely covered in trichomes, spring directly from the rootstocks . 50. Because of this most of the vineyards in Argentina are planted on ungrafted rootstock .
