It's been a slow year for my hops. The gray, rainy June stunted the vigorous growth of May, but they seem to be back on track. I also added some more fertilizer, in the form of an organic fertilizer tea, which has helped. I need a bigger pot for my Cascades, they're pretty rootbound. But the Chinooks and Centennials are doing well and the new Tettenanger rhizome is settling in nicely. But as usually, an annual problem has finally arisen.
Hops are fairly easygoing plants overall, but they suffer from a few problems. First among them is everyone's favorite little green bastard: the aphid. Aphids love hops. Left unchecked they will blanket the newly grown leaves and the apical bud, they'll infest the hop cones, and they'll seriously stunt the bine's growth. If you see aphids you really need to get on top of it, ASAP.
Depending on how large the hops have grown you can do several things to fight aphids. Commercially, industrial pesticides are used. And to be fair, there are times when they are really infested that I think "Man, a little Diazinon would show 'em what for!" Which is one of the reasons that organic hops are so hard to come by. It's just so much easier to spray insecticides. But there's a geographical component to the problem too. Three-quarters of the country's hops are grown in the Yakima Valley, and the fields usually touch each other. Organic certification would be difficult for any one field, as the spray from his neighbors would reach his fields. Plus the social flak of "Hey neighbor, I now have to spray my fields more because your organic field is just a nursery for pests and diseases!" Add the economics of it all and you can see why organic hops are somewhat rare. Which is partly why they have been exempted from the Organic certification for beer. Well that, and I imagine that AB-InBev's 'Stone Mill' Organic Pale Ale would use all or most of the country's current production.
But if you are growing at home you can be as organic as you want to be. Not being stuck with an economy of scale, you can use a few more labor intensive methods.
If the plants are small you can just use your hands, crushing and flicking the pests off as best you can. You can use a water jet to blast them off. You can use an insecticidal soap, which works but I've found it's not usually great for the leaves. Or you can set your own biological control in motion: release the swarm!
Ladybugs. Lots of ladybugs. 1500 ladybugs. Picked them up at Swanson's Nursery for about $12. That'll put a dent in the aphid population.
One of the problems with ladybugs though is keeping them around. It doesn't do you any good if they decide the grass is greener in your neighbor's yard and just take off. So you need to encourage them to see the many perks, amenities, tax-breaks, etc. that your yard has to offer.
I started by sticking them in the fridge once I got home. A couple hours cold makes them slow and hungry. Then I released them as it got dark, since they tend to only fly during the daytime. Since it was right around the Solstice, that was about 10:30 at night. I also prepped their new home. First I sprayed the bottoms of the hop plants with the hose a bit. This gives the ladybugs water to drink and also makes them "stick"; they don't tend to fly when they're wet. It helped that it was gray and rainy for a few days too, they explore more on bright, sunny days. I sprinkled them around the base of the hop plants, and a few more around the garden. Then went to bed.
Then next morning they were all over the yard, and especially all over the bines, happily munching away on the aphids. But it's not really about how many they eat the first time around. Yes, the adults will eat lots of aphids but mostly they're thinking about other adult things: are there mates and is this a good place to lay eggs? If there's enough food around, they ladybugs will start getting it on like a tree-full of monkeys on nitrous. And they did. You see, what you really want are the ladybug larvae, which look like little weird alligators . I've heard they can eat 50+ aphids each, a day. And once they pupate into adult ladybugs the next round begins.
They stuck around in noticeable amounts for a good week or so, and I still see a few around. Hopefully the rest laid lots of eggs before they took off to wherever it is ladybugs go.