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Wednesday, June 23, 2010

Hops in the southeast - a learning experience

Before there are cones, there are flowers. A hops bine as it begins its climb. Photo: HJB

I've recently connected with a group of NC State researchers working on hops production in NC and have begun arthropod surveys in the NC State research planting at the Lake Wheeler Research Farm and several grower locations in western NC. This Monday, I took a trip out to Lake Wheeler to see what might be moving around.

Developing hops cones, the harvested portion of the bine. Photo: HJB.

The most obvious pests currently present are Japanese beetles. This polyphagous, invasive insect is a voracious feeder on many commonly grown ornamental and food crops and appears to have developed a taste for hops.

Japanese beetle injury on hops foliage at Lake Wheeler. Photo: HJB

Beetle feeding along hops bine. Photo: HJB

Several of the bines had Japanese beetle injury on their foliage, and Rob Austin, NC State Soil Science, had treated with carbaryl (Sevin) dust, the white powder visible in the image above. Carbaryl and other conventional broad spectrum insecticides can be very effective against Japanese beetles (a note about pesticide recommendations), but organic pesticide options are limited. Many hops growers are interested in organic production. We do not know how severe of a pest Japanese beetles will be in hops, nor how much summer defoliation is "too much". So at this point, we do not have treatment recommendations for this pest.

As effective as carbaryl is for Japanese beetle, this material has the potential to flare spider mites, which can be an important and difficult to manage pest of hops. If Japanese beetles are present, scout carefully for mites before choosing which material to treat with. We have been monitoring spider mites at 2 western NC hops farms and have found very low populations to date. The populations at Lake Wheeler are higher, and Rob plans to follow up with a mite treatment this week.
Browning on developing hops cones. Photo: HJB

On Monday, we also noticed browning on the tips of developing cones, which several growers have also commented on. In western NC, this injury appears to be thrips related, although there were very few thrips at Lake Wheeler this week. I have also seen some online resources which have suggested that browning can be a sign of approaching harvest.

Arctiid moth caterpiller feeding on hops. Photo: HJB

Caterpillars of several generalist moth species have been observed in hops plantings this spring and early summer. Eastern coma caterpillars were found at several mountain farms, and were subsequently treated with Bt. I found the arctiid (tiger moth) caterpillar in the above photo on Monday. I do not think these generalists are of pest concern at this time, but may be locally problematic.

Young bines at Lake Wheeler. Photo: HJB

A hops field tour, which I will be participating in, is scheduled for July 31 in western NC. As this date approaches, I will be sharing more information.

More information
NC Hops Blog

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