A Decade of Hop Powdery Mildew in the Pacific Northwest

Fig. 5. Spring growth of hop plants (A) and plants ‘pruned’ in early spring by chemical desiccants (B) or mechanically (C, shown here), which removes overwintering buds and shoots infected with Podosphaera macularis. Notice in B that the hop shoots on the hills are brown and desiccated as a result of an application of paraquat + carfentrazone-ethyl. In C, the shoots and several centimeters of the crown have been removed by a modified mower. Both practices aid in eliminating early season inoculum of P. macularis.



Image from Plant Health Progress article:
A Decade of Hop Powdery Mildew in the Pacific Northwest