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.
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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.
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 westernstriped 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
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
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.
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!
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.
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.
…An uncommon phrase to hear in agriculture, but recent floods will have a dramatic effect and have already caused an estimated $12.5 billion dollar loss in the Midwest. Impacts include crop damage, inability to access fields to work ground or plant, and water contamination.
Here at home, the mainstem of the Willamette River and its tributaries (Long Tom, Mary’s, Callapooia) are in huge swells, with property flooding and road closures abundant. For current updates, check Benton and Linn County webpages or ODOT TripCheck.
From an insect pest point-of-view, the changes that may come about are uncertain, but I will be keeping a close ‘eye to the ground’. Flooding could cause mortality for some species (onion bulb mite, beetles, sawflies), promote growth in others (armyworms, mosquitoes), and have little effect on bugs that overwinter in sheltered areas (BMSB and ladybugs).
‘Twas a dreary day when I could finally get out to our research farm to assess damage to fields. However, our farm manager is resilient and those that have lived here longer say it’s “not that big of a deal”. I guess when you live in Oregon with 300 days of rain, you make your own mental sunshine.
The definition of Precision Agriculture has evolved over 22 years and has more than a few associated acronyms (PA; SSCM=site-specific crop management; VRT=variable rate technology).
If one were to attempt to summarize the definition of PA: it involves awareness of growing conditions within a field and the use of technology as a decision support tool to maximize production efficiency while minimizing environmental impact of agricultural inputs.
We may be most familiar with PATs (Precision Agriculture Technologies) such as GPS-guided tractors or the use of UAVs (unmanned aerial vehicles AKA “drones”) as imagery sensors or product applicators. So many acronyms! Other PATs include robot weeders and mechanized transplanters.
Check out The University of Sydney’s Australian Centre for Field Robotics promo video:
Resources closer to home include the UAS at OSUprogram, and a fellow Beaver blogger who has a great annotated resource list about Drones in Agriculture here. UAVs are even being used for restoration seeding efforts in Oregon rangelands.
Perhaps you’re not quite ready for autonomous tech. One simple and easy way to jump on the PA bandwagon is to use calibration tools. These are based on mathematical models of soil and crop parameters for a specific latitude, soil type, etc.. At the click of a button, they provide output estimates to help schedule irrigation, determine fertilizer needs, or predict harvest dates. These are in addition to the MANY mobile apps now available.
Another new trend (and a way to sneak in one last acronym) is for companies to offer SaaS: Software as Service, like our friends at Valley Agronomics.
As you go about planning and planting this year, why not give these PA tools a try. The program developers are usually very receptive to comments, as it helps them improve the models, or know that they are working adequately.
DISCLAIMER: Mention or links to any of the products or services above do not imply endorsement.
Insecticides should not be the only plan of action when trying to control insect pests. But they are also an important and valuable tool. The National Roadmap for IPM supports chemical management as an option, but a main focus is to reduce the risk of resistance that may develop when a system relies too heavily on chemical management strategies.
Active ingredients in pesticides target different aspects of an organism’s growth. So, when implementing an insecticide use plan, it is very important to try to rotate chemistries, also known as modes of action (MoA).
Familiarize yourself with pesticide ‘group numbers’, and try to make choices that AVOID repeated use of the same product or MoA group. Otherwise, you may inadvertently be contributing to insecticide resistance, which means that sprays will be less effective, wasting your time and money. Group numbers are usually shown on a product’s label.
If you want to know more about this concept, may I suggest this video and other material available from the Int’l Resistance Action Committee (IRAC-online(dot)org). Other great resources include OSU’s Integrated Plant Protection Center (IPPC) and the National Pesticide Information Center (NPIC).
For those of you I met at the OSU Extension Annual Conference in Corvallis (Dec 3-6 2018), it may be helpful to click here to learn more about the VegNet program, or feel free to contact me if you have questions.
Armyworms may be a problem in grass seed, pastures, fall-seeded brassicas, etc. this winter. Some species overwinter as larvae and can continue to feed if temperatures are mild enough. Check out the recent articles on our sister blog, Cutworm Central.
Continued and planned updates to the pest profile page, including Lygus bug…coming soon!