Growing Hops – part two Pests and diseases an extract from Brewing Britain –
When growing hops aphids can be a problem. To combat them I pick as many ladybird larvae (young ladybirds) as I could from a nearby lime (Tilia) tree and placed them on the bines, where they made short work of the aphids. This is best done as soon as you see any aphids. Aphids are born pregnant and sometimes even with a pregnant aphid inside them, so these little critters multiply quicker than rabbits.
Powdery mildew can also be a problem. This is a fungus that appears in small, circular powdery colonies on the leaves. It grows just like mushrooms do, spreading a web of mycelium (fungus roots). If left untreated, the whole bine can turn white. The fungus can also stop the flowers (or burr) from forming altogether and yields may drop to next to nothing.
Prevention, as always, can be better than cure. As powdery mildew can over-winter on hop debris, ensure all above-ground growth is destroyed each year and consider planting disease-resistant varieties such as Boadicea, Wye Target, Magnum or Newport, or moderately resistant varieties such as Fuggle, Perle and Hallertau. Also, do not over-fertilize with any nitrogen-based fertilizers, as the disease will strike young growth rather than established growth and the nitrogen will aid young, fresh, disease-susceptible shoots. When watering, water just the roots, or consider setting up an irrigation system and water first thing in the morning to stop humidity levels rising – mildew loves high humidity levels.
Inspect plants regularly and, if infected, remove and destroy all infected parts, normally the bottom leaves. This also opens up the hop area and helps to decrease humidity. Some hop growers have reported good results from spraying with a solution made up of 50% water and 50% cow’s milk.
When growing hops don’t forget, hops are greedier than city bankers: they will need nutrients and lots of them. It is good to know the warning signs of any deficiency and what to do to rectify it. Leaves turning yellow, leaves falling off or curling, and slow growth are all signs of mineral deficiencies. These can be easily rectified by feeding with a liquid seaweed feed; if that doesn’t work, try digging wood ash into the soil around your plants. I’d also suggest using a comfrey feed, which is made simply by adding comfrey to a water butt then watering your plants with the ‘tea’ – or there is always the less smelly option of mulching with comfrey.
Have you been growing hops? Let me know how you got on in the comments below.
Brewing Britain is available from many great bookshops, including Blackwells in the UK and over in the US of A – you can buy it from your local indie bookstore or if you live in Australia and want to be of the minority that makes good beer, buy it here. Then there is the rest of the world… if you want to email me, I’ll find you a bookseller or perhaps I’ll even sell you a copy myself.