Conserv FS News
WHAT IS MAPLE TAR SPOT DISEASE?
Maple tar spot is a very visible problem for maple trees. It starts with small yellow spots on growing leaves, and by late summer these yellow spots expand into large black blotches that look just like tar has been dropped on the leaves. This is because a fungal pathogen in the genus Rhytisma has taken hold.
When the fungus initially infects a leaf, it causes a small 1/8-inch-wide yellow spot. As the season progresses, that spot spreads, eventually growing up to 3/4 inches wide. The spreading yellow spot also changes colors as it grows, slowly turning from a yellow-green to a deep, tarry black.
The tar spots do not emerge right away but are typically obvious by mid to late summer. By the end of September, those black spots are at full size and may even appear to be rippled or deeply grooved like fingerprints. Don’t worry, though, the fungus only attacks the leaves, leaving the rest of your maple tree alone.
The black spots are unsightly, but they do not do any harm to your trees and will be shed when the leaves fall. Unfortunately, maple tree tar spot is spread on the wind, which means that your tree can get reinfected next year if spores happen to hitch a ride on the right breeze.
Maple Tar Spot Treatment Because of the way maple tar spot disease is transmitted, complete control of maple tar spot is virtually impossible on mature trees. Prevention is the key with this disease, but if nearby trees are infected, you can’t reasonably expect to destroy this fungus without community support.
Start by raking all your maples fallen leaves and burning, bagging, or composting them to eliminate the closest source of tar spot spores. If you leave the fallen leaves on the ground until spring, the spores on them will likely reinfect the new foliage and start the cycle again. Trees that have trouble with tar spots year after year may also be struggling with excessive moisture. You will do them a great favor if you increase the grade around them to eliminate standing water and prevent moisture build-up.
Trees may require treatment, especially if other trees have had a lot of their leaf surfaces covered by tar spots in the recent past. If you’re planting a younger maple in an area prone to maple tar spot, treat tar spot by applying a fungicide, like bayleton and mancozeb, at bud break and twice again in 7- to 14-day intervals is recommended.
GRASS SEED GERMINATION
Grass seed will germinate at a wide variety of temperatures; the optimum temperatures for germination are in the table below. The temperatures listed are air temperatures which would be almost identical to that in on the surface of the soil barring radiation effects.
Realize though that optimum temperature for seed germination can vary depending on seed age, cultivar, etc. Also, the optimum germination temperature of certain species may not involve a specific temperature but a rhythmic alternation of temperatures. Additionally, the maximum and minimum temperatures for seed germination are poorly defined because of the extreme slowness of germination, especially for the minimums.
Most of our cool season grasses can germinate almost throughout the summer, so there are many other factors control the success of seeding. Poor irrigation, diseases like damping off, and weed pressure are the most common causes of seeding failures.
Optimum Temperatures for Seed Germination
| Turfgrass Species | Optimum temperatures for seed germination (degrees F) |
| Creeping Bentgrass | 59–86° |
| Annual Bluegrass | 68–86° |
| Kentucky Bluegrass | 59–86° |
| Rough Bluegrass | 68–86° |
| Tall Fescue | 68–86° |
| Red Fescue | 59–77° |
| Sheep fescue | 59–77° |
| Chewings Fescue | 69–77° |
| Perennial Ryegrass | 68–86° |
| Intermediate Ryegrass | 45° + |
2020 SEED REVIEW / 2021 OUTLOOK
In terms of seed, 2020 was a record year for many turf seed growers in the Western US. With travel being limited (or non-existent) and vacation plans canceled, homeowners focused their time, attention, and resources (money!) on improving their lawns. Garden centers had great years and grass seed was a hot commodity. As the new crop was harvested in late Summer, prices started to drift upwards as there was very little carryover from the previous crop due to the high demand. As Fall commenced, landed costs were further strained due to severe shortages in trucking, which will continue into 2021.
As we enter 2021, seed availability is extremely tight and major grasses are already sold out until new crop is harvested in late Summer/early Fall. In other cases, some growers are holding onto what limited inventory they have with the hope prices will continue to strengthen. Perennial Ryegrass & Creeping Red Fescues have seen the largest shortages, with quality (higher weed content) a major issue. In essence, demand has been outpacing supply since Spring of 2020. With all that being said, I am happy to say that we anticipated these issues in the Fall and have locked up the majority of our needs for the coming season, while upholding our high-quality standards. With over a combined 100 years of grass seed buying and knowledge in Lisle alone, rest assured we have you covered in these challenging times.
2021 Fertilizer Outlook
Urea
Crop prices running up to multi-year highs, and the strongest farmer pre-pay for fertilizer in many years, the demand for inputs has exploded. In the last 2 weeks Urea has traded up $60-$70+/ton and has continued to show strength. We are currently at a 3-year high. The last time we have seen prices this high was in 2014. We are now the highest priced Urea in the world and exporters are trying to line up vessels to ship to the U.S.A. The adage of "high prices cure high prices" is in full effect but will take time.
DAP
Phosphates are way up this year as well. Mosaic has petitioned the federal government for a Countervailing Duty Claim against Russia and Morocco for sending Phosphate here and subsidizing it. While we waited for a judgment all summer/fall, nobody would send DAP/ MAP to our country for fear of back charging the duty on previous ships that arrived. This created a shortage, and DAP has increased over $100/ton. They have now set the duty at +15% but will not have a final judgment until the end of March. When the final judgment is made, our market should return to normal imports with production and future pricing stabilizing.
Potash
Potash has been increasing this year as well. We hit multi year lows in the summer of 2020, and since then, have been on a steady climb as supply fell short. Producers shut down their mines this fall for turnaround maintenance while farmers took advantage of a late all to get in the fields. Ultimately, our country ran short with producers sold out until March causing the rise in price. These products appear to have made their move up for spring and will probably be at these current prices until we reach a more normal Supply/Demand scenario. Hopefully, that occurs sooner rather than later, but only time will tell.
INVASIVE PLANTS
Would you be surprised to learn that ornamental plants in your yard may be causing natural areas to suffer? Some of the more aggressive plants common to backyard gardens are escaping to natural areas, where they choke out other plants and begin to take over. Even if they are pruned and kept in check, their seeds are dispersed by birds, animals, and the wind.
Invasive plants and animals threaten the nation's environment and economy. In fact, the threat they pose to native plants, animals, and ecosystems is second only to habitat destruction. Nearly half the threatened or endangered species are at risk due to competition with invasive species, and combating invasive species is costing the United States nearly $125 billion each year.
In natural areas of the Chicago region, invasive plants are choking out other plants and destroying habitats. Some of the worst invasives in Illinois are purple loosestrife, Japanese and bush honeysuckles, garlic mustard, and buckthorns. "Serious invaders of natural areas are compromising the ability to preserve biodiversity," says the Garden's director of plant science and conservation, Dr. Kayri Havens.
In Illinois, the biggest offenders include buckthorn, bush honeysuckle, and garlic mustard. Other widely planted invasives include Oriental bittersweet, burning bush, and autumn olive.
C20 SOIL BUILDER
Benefits
- Increases Soil Microbial Activity
- Decreases Soil Compaction
- Increases Water Retention
- Enhances Root Growth & Proliferation
- Increases Chlorophyll Production
- Increases Photosynthesis
- Improves Survival Rate of New Plantings
- Consistent Formulation
- Predictable Results
- Multi-Year Performance
WHAT ARE BLENDED ICE MELTS, AND HOW DO THEY WORK?
In a blended ice melt product, there are four main melting granules:
- Sodium chloride,
- Potassium chloride,
- Calcium chloride
- Magnesium chloride.
The advantage of blended de-icing materials lies in the fact that they are economically priced and still have the ability to work quickly at low temperatures. In melting ice and snow, the formation of an ice melting brine is key. Brine acts much like a lighter fluid as it ignites the melting process. The specific chloride, or combination of chlorides, that is applied and the amount applied dictates the speed and efficiency of the melting process.
Blended ice melt products bring together two or all the granular chlorides, in different percentages, for an infinite number of melting formulations. All these blends have their own unique advantages and melting temperatures based upon the percentages of each chloride used. A blend containing high percentages of calcium chloride and magnesium chloride is going to react faster and work to lower temperatures. Calcium and magnesium chloride, in their purest form, react very quickly to begin the melting process.
Potassium chloride and sodium chloride are not fast-acting and take longer to activate, or in other words, take longer to form a liquid brine. Calcium chloride and magnesium chloride are hygroscopic ice melting materials. Unlike potassium and sodium, they draw heat from the air throughout the melting process, causing a quick formation of a faster, more effective brine for de-icing. Potassium and sodium chloride do not attract heat from the air; instead, they simply react chemically with the snow and ice to lower the melting temperature. This process is slower, and the brine formed is less likely to work as the temperature drops.
When used in combination, chlorides of greater power can cause a synergetic effect to increase the melting performance of less effective chlorides. When calcium and magnesium chloride form a brine, they in turn cause sodium and potassium to form a brine faster than if used alone. It is this effect that allows blended ice melts to compete in performance with many of the stronger, more expensive straight de-icers like 100% calcium chloride and 100% magnesium chloride. Blended ice melting products deliver performance at a reasonable price and without the hazardous environmental effects of using a straight de-icing product. For more information on Ice Melt products, visit www.icemeltchicago.com
FALL TASKS FOR COOL-SEASON LAWNS
As temperatures drop in late summer and early fall, cool-season grasses peak in growth. These grasses include northern favorites such as Kentucky bluegrass, perennial ryegrass and tall and fine fescues. Warm days and cool nights make fall the perfect time for establishing new grass and strengthening existing lawns. The following fall tasks help cool-season lawns flourish:
- Soil Test. Fall soil testing helps take the guesswork out of managing your lawn's soil pH and nutrition. By making recommended improvements in fall, soil amendments have extra time to complete their work and prepare your soil before spring. lawns come spring. Test healthy lawns every three to four years, but test problem areas every year.
- Fertilize. Fall fertilizing varies from your regular-season plan. With summer dormancy behind them, cool-season grasses benefit from fertilizing. A high-nitrogen fertilizer helps lawns establish vigorous roots.
- Overseed thin lawns. Fall conditions are ideal for germinating cool-season grass seed. Overseeding thin lawns pays off with thick, strong, spring grass.
- Aerate compacted soil. Compacted soil restricts root development and limits soil oxygen. Aerators correct compaction by creating openings in the soil.
- Keep watering. Actively growing, cool-season grass needs water. But as fall approaches, you can stretch out regular watering and let rainfall help. Healthy, established lawns generally need 1 inch of water, including precipitation, weekly. As growth slows, that same amount may cover 10 to 14 days, under normal conditions.
- Control weeds. With weeds still going strong in early fall. Tackle tough weeds with targeted spot treatments. Avoid newly seeded areas.
Overseeding this Autumn?
Click below to view our grass seed mixtures:
Using Indicator Plants and Growing degree days Information as Pest Management Guides
Researchers have been determining Growing degree days numbers associated with life stages of many species of pests and stages of development of various indicator plants. Informed landscape plant managers are using this information to make wise pest management decisions.
For example, years of careful observation have shown that the eastern tent caterpillar is a young larva and most vulnerable to control measures, between 100-200 growing degree days. This is also the GDD range when saucer magnolia, Magnolia x soulangiana, is in pink bud to early bloom. A landscape manager can observe the development of local saucer magnolias to pinpoint the best time to treat or remove the small eastern tent caterpillar nests.
Another example: Suppose pine needle scale has been a problem in past years and a grounds manager wants to prevent further outbreaks. By checking references such as Coincide: The Orton System of Pest Management, he or she learns that the eggs of pine needle scale hatch and first generation crawlers are most vulnerable between 200 to 350 GDD. This is also about the range that horsechestnut, Aesculus hippocastanum, blooms. When 150 GDD have accumulated, or when horsechestnut just begins to bloom, it is time to scout pines for newly hatched pine needle scale crawlers. Since the crawler stage is the most easily controlled life stage, when crawlers are observed, it is time to treat with a registered material.
Plant phenological indicators are only guidelines. Grounds managers still have to monitor pest life stages to pinpoint what is happening at each site. Likewise, specific events in insect development occur within GDD ranges, not by a specific number. Tracking GDD and phenological indicators gives a useful way of knowing when to look for a particular pest and to manage it in its most vulnerable stage. Following signals in nature helps arborists, nurserymen, and grounds managers make effective pest management decisions and minimizes the impact of their pest control applications on the environment.
Magnolia scale
Magnolia scale eggs hatch internally and the crawlers emerge from the mother insect. Crawler emergence occurs late summer into early fall. Insect life cycles are dictated by heat so emergence of crawlers will vary from year to year. On average crawler emergence occurs from late August through the end of September. This would also be the best time to treat with insecticides. The crawlers move around until they find a suitable feeding site, usually on branches, where they settle down and remain through the winter. The adult female dies after reproducing, but may remain attached to the stem for many weeks, making the population seem larger than it really is.
Damage
Scale insects have sucking mouth parts and feed on sap from the tree. They can remove large quantities of sap and can stress the host tree. Trees can usually tolerate small populations of scale. The extensive feeding by a larger population will stress the trees and often leads to yellowing of leaves and twig dieback. Over time, an untreated population of magnolia scale may lead to decline of the tree.
Excess sap is excreted by the insects as honeydew. Honeydew is sticky and will coat plant parts and often drip onto surfaces under the tree. A black fungus called sooty mold will grow on the honeydew, but does little actual damage to the plant. The sticky honeydew and black sooty mold are often noticed before the insects are seen. The honeydew may also draw other insects like ants and wasps to the tree.
Hosts
Magnolia scale will attack magnolia trees and tulip tree. Star magnolia, saucer magnolia and many magnolia hybrids are most commonly and severely affected.
Anthracnose
Rain has been over-abundant in the last couple of weeks. So, of course, it is no surprise that anthracnose is already showing up. Anthracnose is primarily a foliar disease affecting many deciduous trees including ash, elm, oak, and maple. So far, all the reports we have received have been on maples, but it is likely other species are showing symptoms and we just have not heard about it. Leaves are already heavily spotted. Often, we don’t see a lot of defoliation with anthracnose (except for sycamore anthracnose), but infections on maple seem to be severe enough this year to be causing some defoliation. This will not be fatal, but it will put some additional stress on trees as their “food factories”, the leaves, drop off prematurely. The food that trees make for themselves is different from what fertilizers provide, so extra fertilization is not warranted.
The fungi are able to infect the young, tender leaves, especially during cool and wet springs, like we’ve been having this year. The disease is caused by several different fungi. The fungi are host specific, so the maple fungus doesn’t infect oak trees, and so on. Symptoms vary with the plant host, weather, and time of year when infection occurs, but this disease often produces brown or black blotches (fig. 10) and curled or twisted leaves. Infection is more severe when prolonged spring rains occur after new growth is produced. Although the symptoms appear in late spring into the summer, the initial infection took place in the early spring at bud break and before the leaves hardened off. Once the symptoms show up, it is too late for any chemical applications to be effective.
Management: Cultural methods are usually sufficient to reduce the severity of anthracnose in our region. These include:
- Pruning trees to open up the canopy for better air circulation.
- Maintaining tree vigor with proper watering during times when rain is inadequate.
- In the fall, cleaning up and destroying fallen leaves to reduce the source of inoculum.
Cedar Rust
We have received photographic evidence in our Plant Clinic email this week to show that the cedar rust galls are producing their telial spore horns and producing spores. I went to my back window to check my neighbor’s poor juniper. On Tuesday morning, I could not see any spore horns, but by Wednesday noon, I did not need the binoculars to confirm the horns are expanded. They are fully expanded due to the rain this week. All three cedar rusts (cedar-apple, cedar hawthorn and cedar quince) are active now. If you have not started protective sprays on the deciduous host, it time to get going!
Source: Morton Arboretum
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