The Asian longhorned beetle is a threat to America’s hardwood trees. With no current cure for infested trees, early identification and eradication are critical to prevent the loss of more trees.
August is the most critical time of year to spot ALB as adult activity peaks. That’s why the U.S. Department of Agriculture (USDA) declared August as “Tree Check Month” for this invasive pest. Checking trees for the beetle and the damage it causes is how everyone can help USDA and its partners eliminate the beetle from the U.S. and protect more trees. USDA and its partners are working to eradicate the tree-killing beetle in Massachusetts, New York, Ohio and South Carolina. However, residents in all states should keep an eye out for any new incursions.
ALB is an invasive wood-boring beetle that attacks 12 types of hardwood trees in North America, such as maples, elms, buckeyes, birches, and willows. Infested trees do not recover and eventually die. Infested trees also become safety hazards since branches can drop and trees can fall over, especially during storms. In its larval stage, the insect feeds inside tree trunks and branches, creating tunnels as it feeds, then adults chew their way out in the warmer months, leaving about ¾-inch round exit holes.
Source: USDA-APHIS
Native stingless wasp may benefit ALB eradication efforts
For 25 years, the USDA-APHIS Plant Protection and Quarantine program's Asian longhorned beetle (ALB) eradication program has successfully battled back against the pest to significantly reduce its footprint. PPQ experts have established a solid response plan to eliminate the ALB and prevent its spread to other locations. As part of PPQ’s ongoing efforts, scientists are evaluating a biological control (biocontrol) agent—Ontsira mellipes—for its potential to attack and kill ALB larvae.
This stingless parasitoid wasp is native to North America, abundant, and widely distributed across the continent. Ontsira mellipes attacks larvae of native woodboring cerambycids (longhorned wood-boring beetles) and the ALB—a non-native cerambycid—in laboratory tests. For this reason, scientists are hopeful that the wasp can aid ALB eradication efforts. To prove it, they have teed up biocontrol field studies in the ALB quarantine area in Worcester, Massachusetts.
PPQ’s Science and Technology researchers Juli Gould, Carrie Crook, Mandy Furtado, and Theresa Murphy are working with colleagues from USDA’s Agricultural Research Service (ARS), the University of Massachusetts Amherst, and PPQ’s ALB response team to evaluate Ontsira mellipes as an effective biological control agent. They will conduct their 18-week study off the beaten path on conservation property in woodlots where public usage is limited, and ALB quarantine regulations are in place.
Graceful and spectacular are perfect words to describe the wedding cake tree.
All photos by Mark Leichty
There are few trees that I would describe as breathtaking. However, a planting of three mature Cornus controversa ‘Variegata’ triggered such a strong emotional reaction when I saw them recently on a garden tour that there is no better word to describe them. Commonly called variegated giant dogwood, or wedding cake tree because of the layered look of the branches, this magnificent tree simply cannot be overlooked. The alternating leaves are green with wide margins of pure white extending to edge of the leaf. The green part is artfully serrated giving each leaf a uniquely beautiful pattern. At a distance, the overall appearance of the tree is white, and well cultured specimens have a very distinct layering of the branches, giving rise to the common name wedding cake tree.
Cornus controversa is native to China, Korea, and Japan. It has given taxonomists some challenges since it was first documented in the early 19th century. Most members of the genus Cornus have opposite leaves. C. controversa has alternate leaves and was first named Cornus macrophylla. It was later called Cornus brachypoda in an 1845 publication and that name was accepted in western Europe and America. Around 1890, Veitch Nurseries in Exeter, England, introduced a variegated form and called it Cornus brachypoda ‘Variegata’. It was Danish botanist and surgeon Nathaniel Wallich who suggested the name Cornus controversa which we use today, and thus C. controversa ‘Variegata’ is now the accepted name of this beautiful tree.
It grows best in light shade in well-drained soil. In May, it produces lacy white flowers that develop into black berries by late summer that are loved by birds. The flowers provide nectar for bees and butterflies. Given regular water and room to spread, the stunning “layer cake” effect is soon evident. C. controversa will be the bright star in any garden!
Mark Leichty is the Director of Business Development at Little Prince of Oregon Nursery near Portland. He is a certified plant geek who enjoys visiting beautiful gardens and garden centers searching for rare and unique plants to satisfy his plant lust. mark@littleprinceoforegon.com
Lean transformation
Features - Nursery Optimization
The team at Oregon-based JLPN Inc. shares what they’ve learned during the last 5 years of pursuing the ‘Least Waste Way’ of doing business.
Having multiple configurations and sizes of nursery carts reduced the number of trips across the nursery we have to make to load or unload a greenhouse. All trailers fit through the doors of any greenhouse so everything can be moved mechanically.
We can think of no more effective way to optimize a nursery than to remove waste. To explore this, The Peters Company visited JLPN, Inc. and spoke with owner John Lewis and his leadership team about the transformation of this third-generation tree seedling and liner grower. Lewis was joined by shipping/propagation manager John Pedersen, field manager Jeremy Powell and Lean manager Carlos Vergara.
Here are highlights of the interview. For the full case study, visit https://bit.ly/JLPN-lean.
How did JPN get started with Lean?
Lewis: Six years ago, a customer came by—Chris Robinson, Robinson Nursery. I showed him a new piece of equipment that would be a major labor saver. As I showed him the machine he said, “You're basically doing Lean.” And my response was “What's Lean?” He explained the concept and said Robinson was part of this group called the Oregon Lean Consortium with Rick and Liz Peters. Within a week we were in the Lean Consortium.
How did your team respond to that?
Lewis: They probably thought, “Here we go again. John's got a big idea.” And I was like, “No, I mean it this time. We’re doing this to stay competitive. We have fewer people every year. We need to figure out how to do more with less.”
Pedersen: My first reaction was “Here it goes. Something new–and more work.”
Powell: There's fear of not knowing what we're doing when we start. You'll automatically try to protect yourself from the unknown, right?
Vergara: When they started talking about making the job easier and getting more product out without being tired at the end of the day, I was like, “Oh yes, we need that here!”
Lewis: While they were all, “Here we go again,” I didn't waver one bit. “No, we are doing this.” And then I had to prove it. The kaizen events started getting people on board.
Talk about your first Lean event.
Lewis: Processing cuttings took six weeks to do and was a 20-person job. It was slow. It created a ton of waste. We walked across the top of our flats and broke them. The material went all over the floor.
Pedersen: We were harvesting first, then going back later and picking up the flats. I guess we were so excited about how fast we were that we had never looked at it and realized we're not being efficient.
Powell: We would go in there and make a humongous mess and wouldn't come back to clean it up for two or three months. When we did come back, it was because we were planting again, and we were emptying greenhouses and planting them the same day. After the kaizen event we got more done and we weren’t working as hard. We thought our numbers would fall, but when we totaled it all up, we saved all this time and money. By then we were asking, “what's the next event?”
Lewis: So, in one event we eliminated $15,000 worth of broken plastic annually. Our labor reduction was around 35-40%. And we didn't stop there. We continued readdressing that same process and cut production time by 50%.
Powell: We went from sending a mass of people into the greenhouse to sending in two at a time, getting the product out of there, leaving almost zero mess. We also eliminated a horrendous amount of lifting.
Lewis: Our cleanup time went from four hours per greenhouse to 20 minutes. With 60 greenhouses it was 400 hours of labor down to 25. We now process twice as many plants with half as many people.
By simply tracking the number of tree cuttings being produced in real-time, JLPN eliminated over-production of cuttings they didn’t need.
You say people are your greatest asset. That sounds nice, but what does it really mean?
Lewis: Everybody needs to be engaged for Lean to work. The only way to give everybody that opportunity is to give them the same education. So, I made it available to anyone in our company.
Powell: The quicker you get on board — and the more people you get on board to support it — the faster you see changes. I wouldn't hesitate to put your whole crew through Lean training, not just your managers.
Pedersen: I agree with that. If you get the buy-in of the crew, you'll see your Lean journey go a lot farther than if it's just your managers.
“Right sizing” the greenhouse use in the JLPN facility, relative to their crop volume size, eliminates the use of multiple houses per crop and creates efficiency.
You now have a staff person dedicated to Lean.
Lewis: I set this up as a position, the same as my production manager or sales manager. Carlos is the Lean manager. I needed someone who was willing to educate himself to a point where he could educate people who had more seniority. He’s done great. It’s been an investment in his career and education, and the return has been fantastic.
Vergara: I thought this program was just going to make things easier. But it's a lot more for me. I'm learning more with Lean than just being a regular employee. I’m creating value for the company. I am growing in a good position.
Where are you spending the most money? That's your first target. That's where you’ll make the biggest wins quickly. It will show your people that Lean works.
What advice do you have for other growers?
Lewis: Look at where you're spending the most money. I’ll admit when I saw the improvement numbers of others, I thought, “These are made up. There's no way somebody saved 75% on a process.” How wrong I was. Our tree seedling grading involved 36 people and took three months. We went to 27 people and increased production by 40%. We cut defects. Quality of our grade became better. So, my advice is to go after the big numbers. Where are you spending the most money? That's your first target. That's where you’ll make the biggest wins quickly. It will show your people that Lean works.
Powell: I think the biggest thing is keeping an open mind. I've seen that person who puts up the wall, like they're being judged. Go into it with an open mind.
A simple piece of steel welded on to the nursery’s clippers gave the workers a gauge for the proper diameter of wood to harvest. This eliminated wasted movements and collection of undersized product that was unusable.
Pedersen: When you get a group of colleagues together and look at a process and listen to everybody's view — with no judgment — that's a big win. Maybe you’re thinking, “There's only one way to do it.” That’s not true.
Lewis: Waste is everywhere. That’s why we did the same process three times. Continuous improvement is just that: you always improve.
Another critical concept is that you will fail without leadership. We've been in the Lean Consortium six years and seen hugely successful Lean companies. We've seen others create success then go back to the way they did it before, because leadership wasn't there.
The battle of the weeds
Supplement - State of the Market: Weed Control Report
Our exclusive research sheds light on weed management practices and control issues. See how your management plan stacks up with other growers.
This summer, Nursery Management magazine surveyed more than 100 growers across North America to learn more about weed management procedures including scouting, herbicide use, budgets and more. The following pages reveal what your peers are doing at their own operations, as well as which weeds are the most problematic.
Editor's note: Due to rounding, not all percentages add up to 100.
Container nursery growers are at a disadvantage compared to some other cropping systems when it comes to weed control because, at least in container production, our only tools are preemergence herbicides, hand-weeding, and mulch. About 25% of growers spend over 100 hours per month on weed control, and with labor becoming more expensive and harder to find, it is becoming more important for growers to improve efficiency in any way possible. Weed control is also expensive. Estimates have shown that growers spend an average of $5,000 or more per acre on weed control, but this just includes chemical costs and labor. What is not included in these estimates is the opportunity cost that is lost when labor is diverted from profit generating/production related tasks (loading trucks, potting, propagation, etc.) to a corrective or profit reducing task like hand-weeding. While weed control is challenging, there are growers in many different parts of the country that have consistently clean nurseries. In each case, these growers are following similar practices that have been shown to work both in research and in the real world. In this article I will describe the five common things I have seen in the most consistently clean nurseries I have visited.
1. They scout daily and hand- weed frequently to reduce weed pressure.
The goal of improving a weed control program should be to reduce hand-weeding labor, but we want to reduce the total time spent weeding, not the frequency. Research out of North Carolina State has shown that weeding every two weeks reduces labor costs by an average of 36% (and some much more) compared with weeding only every eight weeks, or just before herbicides are reapplied (Barker and Neal., 2016). I have visited several nurseries that have adopted this approach, or a similar approach, and have seen tremendous improvements including cutting labor costs for weeding almost in half (or more) and reducing the total number of herbicide applications they need. How does this work? First, most nursery weeds spread exclusively through seeds, and they do not have time to produce seed in two weeks. This reduces the overall weed pressure throughout the rest of the season. This allows subsequent herbicide applications to be more effective because the “seed bank” or weed pressure is low. Secondly, it is time consuming to look for and pull very small weeds. If you keep a two-week schedule, crews can skip over very small weeds and only focus on weeding plants that may go to seed within the next two weeks. For more information including how to implement this in your nursery, see “Frequent Hand Weeding Saves Money” (bit.ly/hand-weeding-NCSU).
2. Sanitation is their most effective tool.
Proper sanitation is discussed in many different Integrated Pest Management (IPM) guides. In terms of weed management, the main principles to follow include:
Hand weed frequently.
Do not recycle potting media. Many growers do this to reduce costs, but savings on soil deliveries can be quickly lost by heavy weed pressure. I have seen very strange (and hard to control) weeds that aren’t normally in containers, such as dollarweed (Hydrocotyle spp.), yellow nutsedge (Cyperus esculentus) and horsetail (Equisetum spp.) show up in pots with recycled soil. If someone is determined to recycle soil, solarization or steam sterilization is one way to reduce pest pressure. If that is not an option or not feasible, at least avoid using recycled soil on herbicide sensitive plants like herbaceous perennials because you will not want to limit your preemergence herbicide options. Using recycled soil only for certain crops like trees in larger containers or in pot-in-pot systems could allow the use of directed postemergence herbicide applications.
Use preemergence herbicides in non-crop areas (walkways, aisles, ditches, etc.). Weeds in non-crop areas will inevitably move into the crop if they are not controlled. Non-selective herbicides such as glyphosate (or possibly glufosinate if glyphosate resistant weeds are present) can be used to control most weeds. While these postemergence herbicides are relatively low-cost, the applicator is not. Tank-mixing a preemergence herbicide in with your post application can significantly improve control and reduce the total herbicide bill by reducing the number of applications that are needed throughout the year.
Clean pots before reusing them. Pressurized water, heated water or steam can be used to reduce weed seed presence and/or viability.
Moving liners and other plants in the greenhouse off the ground. Tables are expensive and not feasible in all cases, but simply moving plants in the greenhouse up on benches can help prevent weed growth in the crop. This also allows the use of postemergence herbicides or Marengo (indaziflam, a preemergence herbicide) to be used on the floor underneath the benches. Other preemergence herbicide options are available if there are no crops in the house when treatments have to be applied.
Start with weed-free liners and keep liners weed free prior to potting.
Stabilize plants whenever possible. Blown over pots can create several issues – first, the herbicide barrier in the top portion of the soil is broken, so weeds have greater opportunity to take over after a pot has been blown over. Probably a bigger issue is that the spilled soil is an ideal place for weed seeds to germinate.
3. They use non-chemical controls.
Certain ornamental species are notoriously sensitive to preemergence herbicide applications (e.g. hydrangea, herbaceous perennials, succulents, tropicals, etc.). These untreated areas can quickly become “hot spots,” or areas where weed growth is concentrated and spreads to other parts of the nursery. Mulch like rice hulls, pine bark nuggets, wood chips, and many others are going to cost much more than preemergence herbicides, but they cost much less than hand-weeding. If the mulch is applied properly (about 1 to 2 inches depending on the situation), a single application of mulch will usually outperform a single herbicide application. Another way I have seen some growers reduce weed pressure is by subdressing fertilizer. While it is usually easier to topdress or incorporate fertilizer, subdressing is a method of “layering the fertilizer” at potting in a single layer several inches below the media surface. When fertilizers are subdressed or layered, the pot is filled halfway at potting, fertilizer is applied in a single layer, and then the rest of the potting soil is added along with the liner. This results in a 2- to 4-inch (or greater) layer of potting soil that contains no fertilizer, and so no nutrients are available to weeds germinating on the soil surface. In research at the University of Florida, growth and seed production of common container weed species has been reduced by 40% to over 90% by subdressing with no negative impacts to several different ornamental species. The benefit diminishes later on in the production cycle when a topdress application is needed to finish off the crop, but subdressing can still provide a benefit early on in the production cycle when plants are most sensitive to weed competition.
4. They select herbicides based on their specific nursery and rotate.
There are over 20 different preemergence herbicide products labeled for over-the-top use in container plant production, but in reality we only have just a few different modes of action (MOA) including Weed Science Society of America’s herbicide MOA groups 3, 14, 15, 21, and 29. With most herbicides, growers are limited to around two applications per year, but in most cases an application is needed every 8 to 10 weeks during the growing season to keep weeds under control. This means that multiple herbicides are going be needed. Another thing to keep in mind is that all herbicides have weak areas, and if you only use one product or just one (or two) MOA, you will quickly figure out the weed(s) that your current herbicide is weak on. To get the best weed control, you need to rotate through different MOA throughout the year, timing the herbicides when they work best for your specific weed spectrum each season. Avoiding back-to-back applications of the same herbicide can also improve crop safety. A list of common preemergence herbicides including their MOA and general weeds they control are included in Table 1. Weed efficacy guides, such as the “2017 Southeastern U.S. Pest Management Guide for Nursery Crops” (bit.ly/SE-pest-control-guide) can be used as a reference for which herbicides are most effective on different weeds, and on which crops these herbicides can be applied. An herbicide rotation should be based on the specific conditions at a particular nursery. I have published a lot of examples of rotations that would work great for some growers but would yield horrible results for others because of differences in ornamentals and weed species. When developing your own rotation, the first priority is making sure the herbicide is labeled for use on the ornamental, or you have determined it is safe by testing it on a small group of plants. The next priority is selecting an herbicide that is highly effective on the most troublesome weed during a particular time of year. As several herbicides are likely effective, the next step would be to select the best option that controls both the worst weed and then the other most common two or three species that are problematic at the same time. For the next application, an herbicide with similar efficacy but a different MOA could be chosen. This process is repeated throughout the year until you have your program developed. Implement that program, take notes, and reevaluate and make changes as needed. Some of the most successful nurseries may utilize four or five (or more) different preemergence herbicide products, using each to take advantage of the products’ strengths such as crop safety or efficacy of key weed species during different times of year.
ATrade names are included for educational purposes only and do not indicate an endorsement. Similar products may be available with the same active ingredient and/or formulation and would be suitable. BMOA = mode of action group based on the Weed Science Society of America. CWeeds controlled only shows broad classifications of weeds. Detailed information is available on product labels and in pest management guides.
5. They make weed prevention an overall priority.
The most consistently clean nurseries all make weed management one of their top priorities. They understand and have seen how much money can be saved by preventing weed issues compared with correcting weed issues. Weed populations (and the associated costs) do not increase linearly, they increase exponentially. In nursery weed control, it is definitely true that a dime spent on prevention is worth a dollar of the cure. With labor being more expensive and harder to find, weed control programs are one area where minor changes can make a big difference.
Chris Marble is associate professor at the University of Florida’s Mid-Florida Research and Education Center, marblesc@ufl.edu.
