Author Archives: greenje

The day the boat turned white: a tale of leafhopper migration

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This is a summary of an article published in the Winter 2020 issue of the Oregon Small Farm News. The article was written by Dr. Toshihiko Nishio and translated and edited by Shinji Kawai and Abigail Hunter, OSU Dept. of Horticulture. The article is available as a .pdf by using the link below.

In 1967, an ocean vessel was in the East China Sea conducting standard atmospheric and marine environment monitoring when, all of a sudden…

Tens of thousands of small insects surrounded the vessel, like powdery snowflakes

Dr. T. NiSHio, rice farming system researcher

Little did the ship’s crew know – that experience would help scientists learn more about a very serious pest problem in rice. In fact, rapid invasions of planthoppers is thought to be one of the major causes of historical famines in Japan.

Ryoichi Kishimoto, who worked at a local agricultural research station formed a group to intensively study the planthoppers. They set up light traps, pan traps, and even windsocks to monitor at different locations throughout the region. In 1971, Kishimoto published his theory about long-range migratory patterns of the pest, which ignited international interest.

20 years after the original observation, another researcher from the same experiment station proved that the planthopper’s migration corridor includes a low-level jetstream from southern China to western Japan. This is how they are able to travel such massive distances in just a few days, and why they would’ve been observed by the ocean vessel.

Learn More

  1. http://www.naro.affrc.go.jp/english/laboratory/karc/
  2. Liu, T., Wang, B., Hirose, N. et al. High-resolution modeling of the Kuroshio current power south of Japan. J. Ocean Eng. Mar. Energy 4, 37–55 (2018). https://doi.org/10.1007/s40722-017-0103-9
  3. Observations by Japanese Meteorological research vessels are still available today!: https://www.data.jma.go.jp/gmd/kaiyou/db/vessel_obs/data-report/html/ship/ship_e.php
  4. Hu G. et al. Outbreaks of the Brown Planthopper Nilaparvata lugens (Stål) in the Yangtze River Delta: Immigration or Local Reproduction? PLOS ONE 9 (2014). https://doi.org/10.1371/journal.pone.0088973
  5. Chapman, J. W. et al. Long-range seasonal migration in insects: mechanisms, evolutionary drivers and ecological consequences. Ecology Letters 18 pp: 287-302 (2015).
Download the article

OACFA resource list

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Thank you for the opportunity to present at your seminars this year. The following is a short list of some of the IPM resources I mentioned during my talk. Thanks for your interest.

Beneficial Birds?

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Some growers tend to think of birds as chronic annoyances. Solutions range from preventative tactics (netting and birddogs) to scare tactics such as artificial predator calls and driving around the farm firing empty shells at murders – sound familiar?

But a new study suggests that certain birds can – and should – be welcomed as a part of an overall sustainable farming strategy. The link below explains:

https://wildfarmalliance.maps.arcgis.com/apps/Cascade/index.html?appid=1ed09c921c1a4e0b94d42934f87f6870

Content source: Wild Farm Alliance. We do not necessarily endorse them nor their views, but are simply providing a link to the report as ‘food for thought’.

That’s a wrap

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The email that went out to subscribers Monday clarified that yes, we are done monitoring and reporting for the 2019 season. You can read that message here.

But please do continue to visit this blog for these and other updates:

  • Summarizing 2019 pest trends
    • A comprehensive written report will be available at the vegetable grower’s meeting and OPVC website by Jan 2020.
    • Investigating why corn earworm was so minimal in W. Oregon but very abundant E. of the Cascades and also in the midwest.
    • Cabbage looper outbreak: if it affected load rejections; possible prediction of outbreaks; how new methods of counting became necessary due to 1200+ moths per trap (see photo below)
comparison of hand tally paper and scale
  • Continued armyworm trapping
    • Cooperators in Tillamook county will continue to operate pheromone traps and scout fields through October because fall activity is common.
    • Trap counts are updated each week http:// beav.es/ZY3 and we are in the process of mapping them to examine if any geographical patterns are evident.
  • Publication
    • 23 years of a darn-solid phenology dataset is nothing to scoff at. I have spoken with some of you about collaborating on a journal article. Dan would be proud, and I…well..need to. Maybe we’ll have enough rainy days this winter to actually accomplish it. Contact me if you’re interested.

Thank you for another great year!

They’re boxelder bugs

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We have received many emails this week about ‘home invasions’ of odd-looking bugs. In each case, the culprits were boxelder bugs. Although easily recognized as adults, the partially mature phase (nymphs) can be unfamiliar.
Nymphs and adults aggregate in large groups, especially on light-colored homes with a warm-facing side. The concern for damage on ornamental or fruit trees is low. Rather, these are considered a nuisance pest. The sheer and sudden numbers of them is what causes calls to come in.

FOR MORE INFO:
https://pnwhandbooks.org/node/6798/print
http://ipm.ucanr.edu/PMG/PESTNOTES/pn74114.html

Week 11 update

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Remember to subscribe to receive up-to-date information via email! We alert you of insect pest activity for nearly half the year (24 weeks), the service is currently free, and we promise to not bother you for the other 28 weeks, nor share your email address.

Notable trends during the week of June 24th include:

  • Cabbage Looper moth counts continue to be extremely high, we are likely seeing the 2nd generation, which is considered the most damaging for brassica crops.
  • Armyworms have wide host ranges but can be especially damaging in grasses, pastures, and field crops.
    • One species, in particular, seems to be booming this year. It is called the “Thoughtful Apamea“, which is closely related to glassy cutworm, but habits and host range are largely unknown.
    • Conversely, True Armyworm is well-studied and we have been collaborating on a project to monitor them in Tillamook County. So far, counts are low, but if you’re interested, trap counts will always be posted here: https://beav.es/ZQM
  • Beneficial Insects include pollinators, predators, and parasitoids that provide some type of ecosystem service. As natural enemies of pests, their activity tends to lag slightly. We have noted an increase in Syrphidae and Tachinidae flies this week, as monitored by passive sampling techniques.

Caution for Cucurbits

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This “CAUTION” post is similar to one I made a few weeks ago for cole crops; a quick way to highlight a potential problem, in hopes that consultants, gardeners, etc., will do some scouting to investigate if/to what extent they may be affected.

We saw, for the first time this season, some western striped cucumber beetle (Acalymma trivittatum) activity on both both weedy volunteer and cropped cucurbits.

This pest is of particular concern because it vectors bacterial wilt, a plant pathogen caused by Erwinia tracheiphila bacteria. Researchers now suspect that, rather than overwintering in the intestinal tract of adult beetles, the bacterium overwinters in the sap of alternate host plants (i.e. volunteer and weedy cucurbit species). The alternate host plants may not show symptoms of being infected, which can make management difficult.

As adult cucumber beetles feed, the beetles become infected with bacterial wilt, and then transmit it to crops. This infection can be direct (feeding on one host then another), or secondary (fecal contamination of already wounded tissue). Once the disease is established, it cannot be managed with pesticides, so ‘awareness’ of cucumber beetle activity levels, and subsequent control if necessary, is considered the best preventative tactic.

A few tips for scouting bacterial wilt in cucurbits:

    • Melons, squash, and cucumber are considered more susceptible than zucchini and watermelon, but all related plants (Cucurbitaceae) are at riska
    • Damage can occur quickly – scout 2-3X/week for beetle pressure and wilt symptoms
    • Symptoms can be immediate on some plants, and not occur until after fruiting on others
    • Leaves may look dull green, yellowing at leaf margins
    • Vines wilt during the day, but seem to recover at night
    • Quick diagnostic test (photos below): stems/vines are cut close to the crown, and a ‘stringy’ sticky substance appears when the two halves are pressed then pulled apart from each other. b

erwinia_knifecutting
1. make a clean, vertical cut close to the crown

2. push segments together then slowly pull apart

PHOTO CREDITS: Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org

 

 

There is a great new eXtension article about biology and management of cucumber beetles in organic farming systems available at: https://beav.es/ZYJ (it’s ok – we’ll use a Beavs shortlink to promote WSU just this once…there’s some great people/research going on up there!)

 

aDISCLAIMER: regional differences in pathogen expression are likely, do not rely on literature from other areas
bDISCLAIMER: may not work for all species or all cases

 

Week 7 update

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If you read this title and wondered “where are weeks 1 thru 6?” .. you need to subscribe! Weekly reports are sent directly by email, but sometimes there is so much happening, I have to do a mid-week update via blog. This is one of those weeks!

  • The cabbage looper outbreak continues, with trap counts averaging 1000 times higher than normal. Yes, you read that right.
  • 12-spot beetles. You see ’em, you know ’em, but did you know they can be devastating underground pests? The pictures below were taken this week on spinach for seed and seedling spinach (yes, there’s a difference).
    • As adults, beetles chew on foliage, flowers, fruit, corn silks, etc.
    • As larvae, grubs chew on and tunnel through roots.
    • For more info about 12-spots, click here; or branch out a bit and learn about the whole rootworm complex that plagues regional growers and gardeners.

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Caution for cole crop plantings

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Over the past few days, I have seen 300+ cabbage looper moths in traps next to fields that aren’t even out of the ground yet, and been texted twice about flea beetle damage. It seems it will be a busy year for brassica pests!

cone trap with about 60 visible looper moths inside
First indication of probable outbreak – May 8th 2019: too early to see this many

All the more reason to subscribe! Stay informed by clicking here. We do not share your information, and many of the pests we report on have wide host ranges, which means the data are relevant for home gardens, nurseries, and many commodity crops.

An example pest report can be seen here: https://mailchi.mp/f504f1497d5b/pest-report-week-4

Update: May 16th

Wireworms in W.OR?

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(Coleoptera: Elateridae) Agriotes spp.
Adults = click beetles; Larvae = wireworms

Spring is a critical time to assess wireworm populations because when soil temperatures warm to 50°F, larvae begin to migrate up within the soil column and seek underground plant tissues to feed on. Root crops are most commonly damaged, but chewing on seeds, seedlings, and fruit also have been reported.

I am coordinating a pitfall trapping effort to determine if non-native adult click beetle species are present in western Oregon (contact me if you’d like to participate). To monitor your own fields, bait stations are recommended, because they are a better indicator of actual, larval (wireworm) pressure.

I will post a more detailed pest profile page in the coming weeks, but for now:

For more information, click the link to read a publication by Nick Andrews et. al re: Biology and Nonchemical Mgmt. in PNW potatoes.

2-may-19 update: the PEST PROFILE PAGE is ready, and has more details about how to monitor, ID, etc.