On forms of the Hop (Humulus Lupulus L.) resistant to mildew (Sphaerotheca Humuli (DC.) Burr.) ; II

Summary

• 1. Individual seedlings of the wild hop (Humulus Lupulus L.) when grown in a greenhouse may be immune as regards leaf and stem to the attacks of the mildewSphaerotheca Humuli (DC.) Burr. This immunity has been shown by the same seedlings throughout the growing season for two consecutive years.

• 2. Such immune seedlings when planted out in the hop-garden may show susceptibility late in the growing season as regards the leaf and “hop” (strobile).

• 3. An immune plant in the greenhouse may show strictly local susceptibility without the general immunity being lost. (Expers 2 and 5.)

• 4. A yellow-leaved female variety ofH. Lupulus is immune toS. Humuli.

• 5. A yellow-leaved male variety ofH. Lupulus is susceptible toS. Humuli.