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…
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.
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.
Tis’ the Season! According to a pest model for this region, the summer generation of brown marmorated stink bug (BMSB) adults start appearing this week. This pest is very mobile, and will move into fall crops readily. I caught a glimpse of an egg mass in sweet corn today (photo below), and nymphs are expected to peak within the next few days.
Bell pepper, sweet corn, and tomato are all considered desirable hosts. Symptoms include sunken kernels, whitening on fruits, and spongy tissue. Rather than re-invent the wheel, I decided to direct you to some GREAT resources (see list below) for BMSB ID and management in vegetables.
FOR MORE INFO:
Wiman lab page – Oregon State University – Identification, monitoring efforts, and resource list
Western Corn Rootworm (WCR) is considered the most important corn pest in the U.S.1 . Most of this damage occurs in the Midwest, where corn acreage dominates the landscape. Over the last 50 years, farmers have used cultural, genetic, and chemical control strategies to lessen the effect of WCR and protect yields.
In comparison, the PNW produces a very small amount of corn (<5% of all regional farmland). Therefore, western corn rootworm has not been a problem for us so far2, and growers are much more accustomed to 12-spots (which is a western variant of the southern corn rootworm – confused yet?!)
Life histories are similar: larvae chew on roots, adult beetles attack foliage and can clip silk if populations are high enough. This interferes with pollination and can lead to poor tip fill.
Q: So why mention WCR if it’s not yet a problem here? A: This species is worth monitoring because it has been moving westward for the past 10+ years, and could become more abundant if corn production increases in the PNW. Yellow sticky traps are great passive sampling tools for many pests, so in short…might as well.
Gray, M. E., Sappington, T. W., Miller, N. J., Moeser, J., & Bohn, M. O. (2009). Adaptation and invasiveness of western corn rootworm: Intensifying research on a worsening pest. Annual Review of Entomology 54: 303-321.
Murphy, A., Rondon, S., Wohleb, C., and S. Hines. (2014). Western corn rootworm in eastern Oregon, Idaho, and eastern Washington. PNW Extension Publication 662. 7 pp.
WEEK 16 – Two types of rootworm are now widely present in the Valley. See this page to learn how to ID and differentiate between them. Another, third species, may be on its way. Western corn rootworm has been moving westward since 2004.
Read the full report here: http://bit.ly/VNweek16 and subscribe on our homepage to receive weekly newsletters during field season. Thanks!