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!
Some current hypotheses (from processors, OSU plant clinic, researchers, growers, field reps):
1. The damage may have been caused by heat stress during a critical time of development. In May and again in July, there were extreme variations of temperature:
2. Auxins are phytohormones known to regulate growth processes in plants, and can spike rapidly in response to heat-shock. Increased auxin levels can ‘present’ as abnormal root growth or phototropism, which was noted at some of the sites:
As auxins move throughout the plant, the gradient shifts and, at least in other types of plants, declining levels causes leaves or petioles to break off. I don’t know much about abscission zones in broccoli, so if you are still reading, please know that these are just my rambling thoughts, and not an official diagnosis. 🙂
3. Another possibility is that young plants were sensitive to residual carryover from synthetic auxin herbicides (2,4-D, Dicamba, Fluroxypyr) remaining in the soil, which is possible with a grass-brassica rotation.
Recently, there has been some concern about odd symptoms of wilting and reduced stands in broccoli and cauliflower here in the Willamette Valley. See photos below.
Symptoms include: Weakened stems – necrosis of lower leaves – poor stand – girdling/calloused tissue at soil level – stem breakage – possible association with weed hosts – abnormal root growth
NOTE: AT THIS TIME, I HAVE ONLY EDUCATED GUESSES OF WHAT MIGHT BE CONTRIBUTING FACTORS TO THE FOLLOWING SYMPTOMS IN BRASSICA FIELDS. THIS ISSUE IS CURRENTLY UNDER INVESTIGATION IN CONJUNCTION WITH FIELD FACULTY AND DIAGNOSTIC LABS.
CRF prefers cool weather and activity tends to diminish during the summer heat.
HOWEVER: Summer activity is measured by pan traps, and
the authors of the model above agree that summer activity might have been underestimated because of ‘visible competition’ and attractiveness of blooming crops and weeds vs. yellow traps. The spring generation can be extended up to 3 weeks or more, depending on how long rainy, cool weather conditions persist. Also, we know that there are overlapping generations of CRF, and a study from California suggests that egg-laying behavior and subsequent damage during summer months is markedly different than fall:
ANOTHER FACTOR is that Delia radicum is actually part of a much larger ‘rootfly complex’, and different species have different ecological niches, behavior, and activity periods. This tableexplains some of those differences. Identifying rootflies is hard enough when they are adults, and nearly impossible as maggots and pupae. Thus, they are referred to as a pest complex that can affect growers year-round.
1According to a regional model (Dreves 2006), and current 2018 data (Agrimet station CVRO)
Seed corn maggot – Poor emergence may be a sign of underground feeding by seed corn maggots, which are the immature stage of Delia platura, the bean seed fly. Plants are most susceptible at seedling stage. Host plants include: green and broad beans, onion, brassicas, peas, pepper, potato, spinach, and beet.
SCM is especially attracted to newly-tilled soil with high organic matter / manure inputs.
They have multiple, overlapping generations per year. This image by U. of Illinois highlights how adults, eggs, and maggots may all be present at the same time.
If emergence is low, scout 2-ft row sections for seed damage and white, tapered maggots that look very similar to cabbage maggot. Both species favor cool conditions for egg-laying, but D. platura are more active as adults in warm weather.
There is a fascinating biological (fungal) control for SCM that alters the fly’s behavior: It causes the flies to settle on tips of grain stems or high-up flowers and die, which increases dispersal of the fungus to spread farther.
Seed bugs– There have been recent complaints of high numbers of ‘small, flying insects’ in both urban and rural areas since mid-April. The bugs are 3-4mm with elongate bodies and wing covers with 4-5 veins. Experts agree that the taxonomy of this group is in need of a major revision, so they are usually referenced to genus level only.
More than half of all known Nysius species are from Hawaii, including the endemic wēkiu bug, that migrates to the summit of Mauna Kea each year.
Nysius spp. are seed predators and tend to be less selective then other, related Lygaeidae. Extensive damage can occur in wheat, quinoa, canola, and sorghum. Occasional feeding can occur on ornamentals, other cereals, and tomatoes.
Similar to boxelder bugs, they are attracted to large, sunny, white buildings, which has led to nuisance reports by homeowners. Various Ask-an-Expert questions have been submitted, one of which I was able to identify last week as Nysius, probably N. raphanus. The high numbers we are seeing now is likely the result of overwintered nymphs maturing into active, winged adults. There are 4-7 generations per year.