Sunday musings about insects & hops

While sending an email to a colleague about insect & hops in North Carolina this morning, I started thinking about the context in which I get questions about insects, especially in new or speciality crops.

From my email, "I think folks focus somewhat on insects and diseases because these are things we have management tools, and answers, for. The harder question to answer is if a crop itself is ready to be grown where people want to grow it. We can recommend a pesticide or cultural strategy for insect management, but we don't know if there are any hops varieties (or other new crops) that will grow well (or well enough to be commercially profitable) in our state. I would rather see this question as the focus of the conversation rather than 'spray X' or 'release predator B'."

Japanese beetle feeding at the Lake Wheeler Hop Yard, 2010. Photo: HJB

The insect questions still arise, however, but I think these need to be pragmatically address in the context of a still unproven agricultural system. Japanese beetles are a common insect seen feeding our hop yard at Lake Wheeler, and I commonly get questions about them from beginning hops growers. I don't think Japanese beetles require treatment unless they are feeding extensively. If mature (second year or older) plants have so little foliage that JB feeding seriously threatens defoliation, the problem is not JB--it's plant vigor, and all the big guns thrown at the beetles are not going to produce a viable crop. Grapes are an excellent example of this--JB feed at the top of the plant, and as long as they don't go below the top trellis wire and are not in fruit, growers do not need to treat. That foliage will be removed anyway. For first year plantings, the scenario is different, but folks should distinguish between baby plants and mature plants in terms of JB management.

Browning on developing hops cones. Photo: HJB

Another insect I got a lot of questions about last year was thrips. We have extremely high thrips populations in the SE, but I have yet to see thrips in cones at Lake Wheeler. This means that the cone browning observed is unlikely to be thrips injury and is more likely to be due to uneven aging associated with our early and prolonged flowering period. I'd hate to see anyone treating for thrips in hops based on cone browning, especially if the browning is observed in the oldest cones.

My thought process around pest management in emerging and new crops is evolving, but sustainability, environmental & economic, remains the key driver of my pest management philosophy. Understanding pest biology is important, but more important is the feasibility of the whole agroecosystem. Although one factor can sink a farming system, everything must work in harmony for it to succeed.

A successful Small Fruits Field Day

Small fruit field day attendees travel by tractor to the IR-4 blackberry planting. Photo: HJB

The 4th NCSU/NCDA & CS Small Fruit Field Day was held yesterday, June 22nd, at the Sandhills Research Station in Jackson Springs, NC. Although temperatures were in the 90s at the start of the event, we had an excellent turn out. About 175 growers, master gardeners, cooperative extension agents, research station personnel, and others joined us to learn about cultural, disease, weed, and insect management in blackberries, blueberries, and grapes. Following remarks by NCSU CALS Research Director David Smith, Assistant NCDA & CS Commissioner Richard Reich, and station superintendent Jeff Chandler, attendees were loaded onto tractor trailers and cycled through presentations by NCSU extension specialists.

Gina Fernandez, NC State Horticulture Department, fresh off sabbatical in South Africa, discussed blackberry and raspberry variety selection and cultural management. Bill Cline, NC State Plant Pathology, covered blueberry disease management. Connie Fisk demonstrated proper muscadine grape training, and Katie Jennings shared information on weed management in small fruits. Both Connie and Katie are also in the NC State Horticulture Department. Roger Batts, from the IR-4 Program, who conducts much of his work at the Sandhills Station, explained IR-4's mission (more here) and detailed the new pesticides that will be soon available due to their work.

One of the highlights of the Small Fruits Field Day is the opportunity to taste in season fruits straight off the plant! Here attendees sample Kiowa blackberries, a thorny variety known for its large fruit. Photo: HJB

In addition to these presentation, I presented 2 of the projects we are working on at Sandhills. We have a spider mite management trial which is currently underway, and we are waiting for the Japanese and green June beetles to show up for a second trial. I will be placing Japanese beetle lures this Friday to foster a population--don't try this at home!

I also described a small blackberry psyllid trial we plan to begin and out ongoing spotted wing drosophila monitoring program. You can read more about blackberry psyllid here. This is an interesting, little studied potential pest of caneberries.

The field day was sponsored by FMC, DuPont, SunnyRidge, Valent, the North Carolina Commercial Blackberry and Raspberry Growers Association, and the North American Rasberry and Blackberry Association. Thanks to these sponsors for their generous support!

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

News & Observer Profile

WNC Vegetable and Small Fruit News - Hops Information Page