Landscape and nursery
§ Black vine weevils will be out soon
§ Update on emerald ash borer treatments
§ Aphids: where do they come from and what should we do about them?
§ Bugs to watch for now
§ Life cycle and management of Fletcher scale on Taxus and Arborvitae
§ Periodical
cicada brood XIII coming this year to
§ Azure agapanthus, queen of the show
§ Going
native with
§ Scouting for weeds: Mouseear chickweed
§ Scouting for weeds: Redstem filaree
§ Scouting for pests: Slugs
§ Pesticide residue testing
Turfgrass
§ Turfgrass tips for surviving summer
§ Chlorothatlonil label update
Christmas trees and forestry
§ Insect update
§ Gypsy moth spray window dates
Other news
§ Weather news
Dave Smitley, Entomology
Nurseries that have had a problem with black vine weevil (view photos) in the past should begin to watch rhododendrons, yews, azalea and other favorite food plants for evidence of spring feeding. Watch for semi-circles chewed into the sides of leaves, and make your first Talstar application soon after you find the new feeding damage. Make a second application two weeks later.
For black vine weevil, it is critical to control adults in June before they lay eggs. Once the eggs are in the soil, sprays are not very effective.
Dave Smitley, Entomology
The original label for Merit 2F allows for up to five
24-inch dbh trees or ten 12-inch dbh trees to be treated per acre with a basal
soil drench of basal soil injection. In some cases in
Soil drenches or soil injections of imidacloprid (Merit and Bayer Tree and Shrub Insect Control) for emerald ash borer should be made at the base of the trunk, not out to the drip-line. The label for Merit instructs arborists to make soil injections for emerald ash borer within two feet of the tree trunk, and the label for Bayer Tree and Shrub Insect Control tells homeowners to drench in a ring around the base of the tree. Our research tests support the use of imidacloprid basal injections or drenches to save ash trees from emerald borer. However, I have now seen several sites where ash trees treated for three years with soil injections of Merit are now dying. In every case, the soil injections were made out to the drip-line of the tree instead of at the base of the tree. If you are using an imidacloprid drench or soil injection, make sure it is done at the base of the tree. Drenches and soil injections will still be effective if they are done in late May or early June.
Dave Smitley, Entomology
A few nurseries have reported some problems with aphids on a variety of plants, and some homeowners have already reported aphids, too. Most everybody has seen aphids on roses, peppers or some type of plant. The small (1-2 mm long), soft bodied, green to yellow or black, insects with twin “tail pipes”, usually come in colonies of 10 or more on leaves, stems or shoots of plants. (View photos) One thing you can be certain of is that there is a kind of aphid capable of feeding on every type of landscape plant. Some of them have complex life cycles, where they feed on tree leaves in the spring, then on the roots of a different type of plant during the summer. Aphids have the advantage of bearing live young, which is unusual for insects. This helps them reproduce very quickly. At an average temperature of 80°F, an aphid can complete one generation in seven to ten days. With each female bearing 40 or more young, you can see how quickly populations can build-up, appearing almost like magic.
Fortunately, we have excellent natural enemies for aphids: parasitic wasps that lay their eggs inside of aphids, ladybird beetles, lacewings, damsel bugs and many others. These predators and parasites keep aphids in check. They are so effective, that under natural conditions we rarely see any problems with aphids. When we see aphid problems on plants, it is usually because an insecticide was applied for some other pest problem, causing a secondary outbreak in aphids weeks or months later.
Long-term management of aphids is simple: avoid using broad spectrum insecticides like pyrethroids, carbamates or organophosphate insecticides. This will allow the natural enemies to return and keep the aphids under control. Restoring natural enemy activity after an insecticide application could take a year or longer. Meanwhile, you may want to use a 1 percent solution of insecticidal soap, or a strong stream of water to dislodge the aphids.
Short-term management of aphids, or the treadmill approach is to spray a pyrethroid insecticide like Talstar, Tempo, DeltaGard, Scimitar, Astro or Asana. This will eliminate the aphid problem for four to eight weeks. After that time, the aphids may come back very quickly, requiring another spray. Many of the products available for homeowners to use in the lawn and garden contain a pyrethroid insecticide. Nurseries and homeowners also have the option of using a systemic nicotinoid insecticide for aphid control. Homeowners can purchase a product containing imidacloprid (Bayer Tree and Shrub Insect Control, and others), while nurseries can purchase Discus, Celero or Flagship to drench around the base of infested plants. The insecticide is absorbed through the roots and should suppress aphids for eight to 12 weeks. Also, you should not see as much of a rebound in aphids after that time, because the systemic nicotinoid insecticides are not as harmful to natural enemies.
Dave Smitley, Entomology
Eastern tent caterpillars are feeding on wild cherries, ornamental
Prunus spp. and a few crabapples. The
caterpillars are over an inch long now in southern
On pine trees, especially Mugho pine, watch for patches of
missing needles, and the green caterpillar-like sawflies eating them. This is
the first sign of European pine sawfly. The sawflies are about done feeding in
southern
We had a report from Bob Bricault (Extension horticulture educator
in
Finally, I hate to say it, but we are fast approaching the
emergence of mosquitoes in southern and central
Dave Smitley, Entomology
Fletcher scale
overwinters as young scales on the twigs and leaves. The small scales (less
than 1/8 inch long) are difficult to see until they begin feeding in May, and
in a matter of a few weeks double their size. Eggs are produced under female
scales in early June. All the live scale insects found in early to mid-June
will contain eggs as only females are known. Eggs will begin to hatch and young
penny-shaped, clear crawlers emerge from under female scales in mid- to late
June. The nearly invisible crawlers soon settle on the needles or green stems
and begin feeding. They grow larger in July and early August. By late August
and early September, some females may again produce eggs. In
The best management strategy for Fletcher scale is natural control. This is what happens in the urban landscape after yews are planted. Predatory insects and parasites keep the scale population to such a low level that they are rarely seen. Some nurseries do not spray anything for Fletcher scale, and have been very successful in growing clean plants. However, when going from insecticide management to natural control, it is likely that you will see an initial outbreak of Fletcher scale that may last one to three years before predators and parasites provide adequate control. Also, natural control may not be as effective in large, clean fields as it is in small weedy fields because predators like ground beetle, rove beetles and ants tend to be more abundant where there is abundant ground cover and a diversity of plants.
If insecticides are necessary, foliar sprays are most effective when sprayed soon after most of the crawlers have emerged in mid- to late June. Crawler emergence can be monitored by finding 10-20 female scales each week, lifting them up and examining the eggs underneath. When most of the eggs have hatched into crawlers, it is a good time to spray then or within the next two weeks. In recent testing, the most effective foliar sprays have been Dursban, Sevin, Supracide, Orthene, Flagship, Tristar, Safari and Discus. The goal of a good foliar spray is to get a thorough insecticide coating on the foliage and twigs. This is best done with spray nozzles that produce fine droplets. Avoid spraying fine droplets when the wind is above 5 mph. Large volume sprays of 100 gal per acre or more put most of the spray on the ground. Remember, fine droplets have a much higher concentration of pesticide (often 100 times more concentrated than large droplets) when you are applying the same amount per acre. If the pesticide label gives the rate in amount per 100 gallons, figure out the amount per acre rate based on 200 gallons per acre, then adjust the per acre rate to your spray volume. Optimum timing in an average year is a single spray in late June for the first generation, and another spray in late August or early September for the second generation.
Several products that are absorbed by plant roots and move
systemically through the plant can also be used as a soil-directed spray.
Successful management depends are good scouting. Every field should be scouted for Fletcher scale in early June and mid-August to determine which fields need to be sprayed.
David Smitley and Gary Parsons
Entomology
Recently, many media
stories have come out about brood XIII of the periodical cicada. Unfortunately,
the media stories do not always give accurate information about where to expect
the cicadas. Brood XIII, like most of the periodical cicadas, have a 17-year
life cycle. 2007 is the next scheduled appearance of this brood. In the last
emergence of brood XIII, cicadas were abundant in some woodlots in northern
The only places in Michigan that are likely to see cicada activity this year are in Berrien, Cass and St. Joseph counties, although a few isolated hot spots may be found in adjoining counties. The cicadas are harmless, other than the high-pitched siren-like whining that they make. The only concern is the twig damage that occurs when the females use their saw-like ovipositor to insert eggs inside of twigs. In heavy infestations, some trees can lose an entire outer layer of small branches to this injury. Valuable trees, especially young ones, can be protected with an insecticide spray in early June to prevent oviposition damage. (View photos)
A South African native, Agapanthus has been cultivated for
centuries as an elegant conservatory plant. (see photo) With recent research
and plant selection, this lily-like plant is becoming hardy to the point of
overwintering even in some west
Otter’s urban garden may not be a true hardiness test because of her unique microclimate conditions. “At some point, you have to get beyond what magazine articles say,” she exclaimed. Even though this beautiful perennial is listed as hardiness zone 7. She encourages other gardeners to try setting out Agapanthus in areas you know in your yard that are somewhat sheltered. For instance, in our back yard, the best spot would be over the septic tank. The soil never freezes there.
Agapanthus love well drained, humus-rich soil and do great in a mixed container. Fertilizer should be applied in the spring as the foliage emerges, and keeping plants well watered will simulate their native setting. Otter said they did just as well for her in part-shade as full sun.
Lily of the Nile freely hybridizes, providing growers with a host of choices in various shades of blue to white, as well as bloom heights. Shorter varieties such as ‘Peter Pan’ and ‘Lilliput’ bloom profusely and can be used in containers or as a border plant. Agapanthus ‘Midnight Blue,’ is known to be very elegant. Agapanthus has attractive, strap-like leaves that are shiny like an Amaryllis. A variegated variety and a few miniatures are also available.
Lily of the Nile, frequently listed as a Zone 7 plant, has not been widely available to gardeners who don’t want to search every mail-order catalog available. With the trend toward plants of a more tropical nature, Agapanthus is likely to become more available at garden centers in the future.
Because of the mild climate, English gardeners see Agapanthus flourishing. Pairing them with spring blooming bulbs, such as Allium cristophii and ornamental grasses that peak later in the season, gives a long season of interest. The long bloom time is very accommodating for a wide variety of mixed perennial border plants and is beautifully paired with the golden foliage of Hakonechloa or ‘Marmalade’ Heuchera.
Container grown Agapanthus can be overwintered in an above-freezing garage, inside the home or greenhouse for winter. They tend to take up the whole pot and then some. Mine is happily sitting on the bathroom windowsill and to my surprise, bloomed white on a three foot stalk in February. Water and fertilizer should be used sparingly during these low-sunlight months, as would most houseplants.
Bert Cregg
Horticulture and Forestry
The topic of planting native trees in the landscape
generates considerable, and often passionate, discussion. For today, we’ll
leave aside the native versus exotic debate and consider some of the other
reasons to select
Whether species are native or exotic, diversifying the mix of species in our urban and community forests helps to reduce the risk of catastrophic tree loss.
Although some natives, such as silver maple or black locust,
are dubious choices for landscape or street tree planting, there are many
Hornbeam (Carpinus carliniana) is a small to medium sized tree that is native to cool moist understory sites. This is a small tree with a big character. Another common name is musclewood, which refers to the muscled appearance of its trunk. It produces a nice display of yellow to red fall color.
Kentucky coffee tree (Gymnocladus dioicus) is becoming an increasing popular choice as a landscape tree. In fact, in some locations demand may outpace supply. This is an interesting medium-sized tree. Once established, coffee tree is considered drought hardy and relatively salt tolerant, making it a common choice to fill the void left by ashes. Its bi-pinnatetly compound leaf makes it botanically interesting. Yellow fall color adds to its ornamental appeal.
The oaks may be considered the forgotten landscape trees, but
they should not be overlooked. Once established, oaks are dependable landscape
trees. There are a number of oaks that are native to
Bur oak (Quercus macrocarpa) is the ultimate “tough tree for tough places.” Bur oak is extremely drought hardy and can handle adverse sites.
Swamp white oak (Q. bicolor), as the common name implies, can handle heavier soils and poor drainage better than most oaks. Aside from lacking fall color, this tree probably comes the closest to filling the role of ash in urban and community forests.
Chinkapin oak (Q. muhlenbergii ) is another overlooked but reliable tree. Chinkapin oak is part of the chestnut oak group meaning it has leaves with serrated margins, similar to chestnut. It is adapted to alkaline soils and has better fall color than bur or swamp white oak.
Red maple (Acer rubrum) is an outstanding landscape tree. Easy to grow. Tolerates wet and acidic soils. Outstanding fall color. Numerous named cultivars are available and trees produced from seed are available from nurseries specializing in native plants.
Striped maple (A. pennsylvanicum) and Mountain maple (A. spicatum) are small trees or large shrubs that are best adapted to moist, cool sites. Both have rough textured leaves with good fall color; striped maple turning bight yellow, mountain maple turning a mottled orange.
Hophornbean or Ironwood (Ostrya virginiana) is a small understory tree. It is noteworthy for its fruit, which resemble clusters of hops. Ostrya is regarded as difficult to transplant but easy to maintain once established.
Note: Thanks to Dr. Bob Schutzki for sharing his insights on outstanding
Steve Gower
Diagnostic Services
Mouseear chickweed: Cerastium fontanum ssp. vulgare
(Hartman) Greuter & Burdet (View Photos)
Life cycle: Patch-forming
perennial.
Leaves: Opposite,
dark green, oval to spatula-shaped leaves with pointed tips and smooth margins
are densely hairy and stalkless.
Stems: Prostrate,
spreading stems are capable of rooting at the nodes to form dense patches.
Stems are slender and very finely hairy with swollen nodes.
Flowers and fruit: Small,
white flowers have five petals. Each petal is notched deeply to resemble a pair
of petals. Green, hairy sepals surround petals.Fruit are slightly curved,
cylinder-shaped capsules that contain many tiny, brown seeds.
Reproduction: Seeds
and creeping stems.
Steve Gower
Diagnostic Services
Redstem filaree: Erodium cicutarium (L.) L’Hér. ex Ait.(View photos)
Life cycle: Prostrate,
fernlike winter annual or biennial.
Leaves: Leaves
are hairy and compound with deeply cut leaflets that give a featherlike or
fernlike appearance. Leaves initially develop from a dense basal rosette and
stem leaves are opposite and sparse. Leaves usually have a grayish tinge.
Stems: Hairy,
semierect stems arise from a prostrate, basal rosette.
Flowers and fruit: Pink
or purple flowers with five petals are found clustered at the ends of long
stalks. Fruit are long, beaklike capsules with five sections; each section
contains a seed with a spirally twisted, corkscrew tail at maturity.
Reproduction: Seeds.
Slugs are worm-like, legless organisms that are often referred to as snails without shells. They vary in length from 1 to 15 cm when full grown, depending on the species. Slugs prefer to reside in moist areas and are active at night. They leave a silvery slime trail, which is most noticeable on sunny days. Slugs vary in color from black, brown, lavender, purple and white to yellow. Several have brown specks or mottled areas.
Management
Remove any hiding places including plant debris, weeds, rocks and wood lying on the soil surface. Avoid overwatering herbaceous perennials to minimize creating moist habitats ideal for slug breeding. Commercial molluscicides can be applied in the evening. It is important to irrigate the area before application.
Steven Gower
Diagnostic Services
Last summer, a
Besides the obvious chlorosis, distortion and browning of the leaves followed by defoliation, there was a spot at the base of each tree that was barren of grass and weeds for several months. I suggested we analyze soil collected near the base of these trees for the presence of residual contaminants capable of causing the observed injury. Unfortunately for the trees, tebuthiuron was detected in the soil at 2.3 ppm. (view photos)
Tebuthiuron (Spike) is a soil-applied herbicide for woody plant control in fencerows, utility right-of-ways, pipelines, pastures, rangelands and other non-cropland areas. Tebuthiuron controls unwanted trees, shrubs and vines after sufficient rainfall has occurred to move the product into the root zone.
In addition to diagnosing plant pathogens, nematodes and insect-related pests, all plant samples submitted to MSU Diagnostic Services – the multi-disciplinary plant health and pest diagnostic facility on campus – are visually inspected for pesticide injury. If warranted, samples can be tested for the presence of pesticide residue using appropriate analytical instruments and techniques.
We urge that clients interested in pesticide residue testing contact the laboratory before collecting and submitting samples. Samples should be collected immediately if pesticide injury is suspected. Collect samples according to visual pesticide expression, as some herbicides affect new plant growth, while others may only affect older growth. Collect enough plant tissue to fill a quart-size plastic bag; collect enough soil to fill a pint-size plastic bag. In general, samples should be frozen immediately and kept frozen until arrival at the laboratory.
Plant samples are visually inspected for pesticide injury for $20. Samples can be tested for pesticide residue on an individual basis or, if available, in multi-pesticide screens. Fees may vary depending upon number of samples, clientele location and numerous other special circumstances. Fees for individual pesticide residue screens are generally $90, $100 and $125 in water, tissue and soil, respectively. Fees for multi-pesticide residue screens are generally $125, $150 and $175 in water, tissue and soil, respectively. Questions regarding pesticide injury or pesticide residue testing should be directed to Steven Gower by phone at 517-432-9693 or by email at sgower@msu.edu.
Kevin Frank
Crop and Soil Science
I don’t think anyone knows what a typical summer weather
pattern in
Avoid heavy nitrogen fertilizer applications as summer gets rolling. Typically, the Memorial Day weekend is the trigger for making a fertilizer application that will help the turf grow throughout the summer months. Search for fertilizers that have some slow release nitrogen in their analysis. Look for terms such as slow release, slow acting, delayed release or natural organic. All of these terms will indicate that the nitrogen will be released at a slower rate than a water soluble nitrogen source such as urea. High nitrogen fertilization applications using water soluble nitrogen sources at this time of year will likely favor top-growth over root growth and won’t help the turf through the summer stress period.
Based on personal observations, I have concluded that the
majority of home lawns in
If you’re not concerned about having a green lawn and rains
are lacking, the turf will turn a lovely shade of brown and enter dormancy. Dormancy
can be thought of as the turf in a resting state, it will turn brown and cease
growing, but will remain viable and resume growth when moisture becomes
available. The cool season turfgrasses in
If you desire a green lawn throughout the summer, there are two irrigation schemes that can be followed. The first is the traditional irrigation schedule of deep and infrequent applications in order to discourage shallow turfgrass rooting, flush salts from the soil profile and reduce weed competition. For those without in-ground irrigation systems, this is most likely the irrigation schedule you’ll follow. Apply between 0.5 to 1.0 inches of water weekly, depending on precipitation and temperature. Depending on your soil type, applying this amount of water at one time may be feasible or may lead to lakes in your back yard. If you have a clay soil, split this application up over several intervals during the day or over a couple days.
If you choose to irrigate your lawn to maintain a green, actively growing turf you need to consider many factors to devise a scheme that works for your lawn. Is the lawn shady or sunny; is the soil type clay or sand; is the turfgrass Kentucky bluegrass or tall fescue; does your community have watering restrictions? All of these factors need to be considered before mapping out your strategy. Here at MSU, we’ve been advocating for several years now to think outside the box and apply irrigation on a more frequent basis than the typically recommended weekly Saturday morning soaking of 1-1.5 inches of water. The light, frequent application scheme has proven to provide excellent quality turf. However, as mentioned above, in some areas irrigating every day may not be allowed by law, so in that case you obviously need to do some tweaking. In those situations, consider watering every other day or maybe every third day – you’ll have to experiment with amounts applied.
What about timing? Generally, avoid irrigating in the early evening hours as this results in the turf remaining moist, damp, and subject to disease activity over the entire night time. If possible, irrigate in the early morning hours. We have also seen benefit from doing very light irrigation (0.1 inch or less) applications during the early afternoon to reduce heat stress. This is particularly effective when trying to alleviate the symptoms associated with the disease necrotic ring spot.
I don’t believe there is one simple irrigation recommendation that is going to work for everyone’s lawn. The key to irrigating successfully is to understand the site, measure your expectations and recognize your limitations, whether it’s watering restrictions or maybe the lack of an irrigation system.
Make sure to stay on top of your mowing this spring to avoid
scalping the turf and thereby stressing the turf. Mow at the high end of the
optimal mowing height range for the turf. For Kentucky bluegrass, mow at 3
inches. Higher mowing heights will help the turf develop a deeper root system. Every
summer you can see damage from mowers or vehicles driving through drought or
heat stressed turf. (view photo) The damage occurs when the turf is close to
wilting or suffering from heat stress. In June 2006, I observed wide spread
heat track damage on landscape turf throughout many areas of suburban
Kevin Frank
Crop and Soil Science
After doing a quick Google search to confirm that I wasn't imaging things - the chlorothatlonil label/use for residential lawns was pulled in 2004. From what I understand, the label was pulled for residential lawns/home lawns. Other uses in the home landscape, excluding lawns, are still allowed.
There are several sources of information, but I found this
link from the
Jill O’Donnell
Christmas Tree ICM educator
We caught our first Douglas-fir needle midge adults in our emergence traps this past week in the Cadillac area. Douglas-fir needle midge overwinters as larvae in soil under infested trees. Needle midge adults emerge in the spring and live only a couple of days, just long enough to mate and lay eggs. The orange eggs are deposited in expanding buds and on elongating needles. Larvae hatching from the eggs immediately bore into the needle, causing elongating needles to form a gall around the larvae. One or more white maggots can be found inside affected needles during the summer. Time your insecticide application within a week of your first trap catch.
Spruce spider mites
Spruce spider mites are often a problem on fir and spruce
trees, but populations can build up on nearly all Christmas tree species. We
have found mite activity on Fraser and balsam fir. Growers should keep an eye
out for the dark mites or their webbing, especially if you had damage from
mites last year. Scout the oldest foliage, near the stem of the tree – that’s
where the mite populations build up first. Rap foliage over white paper or
cardboard on a clipboard. If mites are there, you should see them moving on the
paper. An ovidicide/miticide like Savey is a good choice. Savey controls mite
eggs and immature stages of mites. Savey also does not harm beneficial insects
and predatory mites.
Pine needle scale
Applying insecticides at the proper time is a key element in
controlling pine needle scale. Pine needle scale is most vulnerable to
insecticides during the crawler stage. Although crawlers are tiny, they are
readily visible on the needles, especially if you use a hand lens or magnifying
glass. The ideal time to apply an insecticide spray is after nearly all the
pine needle scale eggs have hatched and most crawlers have reached the hyaline
stage. At this point, the young crawlers are exposed on the needles and have
not yet started to produce the hard, white armor. Spring generation eggs hatch
in May or early June at roughly 300 GDD50.
Usually, eggs hatch within about a week and most crawlers should be in the
hyaline stage by 400 to 500
GDD50 (southern
The characteristic curling of the new growth caused by balsam twig aphid is showing up on balsam fir trees. (view image) Insecticide treatments from this time onward will likely do little to prevent damage; aphids are well protected within the shoots. The good news is that needles will continue to elongate for several weeks. By late summer, much of that damage will be outgrown. One thing you can do for yourself is to make a little map of your field that shows where the trees with the most aphid damage are this year. Then next spring, you will know where to focus your scouting and management activities.
If you are in the Pine Shoot Beetle Compliance Program and
need to apply a cover spray for pine shoot beetle, get ready, especially if you
are in southern
The pineapple-shaped, green to purple galls are now visible
at the bases of new shoots of white,
Each year, I get called out to look at trees that have suddenly died. Sometimes in digging up the tree, we find that it was caused by poor planting. Recently, I looked at trees that had dead branches or the tree had completely died. Looking closely at the trees, we found piles of fertilizer directly next to the tree. Fertilizing a tree can improve growth and quality of the tree, but if it not placed properly can cause damage to the tree. (view image) High fertilizer concentrations can cause damage to branches or roots. Fertilizer should be applied evenly around the drip line of the tree and not closer than a foot from the trunk.
This sprayer application technology for small acreage
producers workshop is on June 14, 2007, 6:00 PM 9:30 PM at theNorthwest
Horticultural Research Station (
The program is geared to all who use spray equipment for small area spraying. It focuses on the various backpack sprayer designs, adaptations and their calibration. Nursery, greenhouse, floral, vegetable, fruit and other small acreage producers will be able to review and work with various backpack sprayer designs, see pressure regulation demonstration, assess nozzle types and accessories and participate in calibrating the various sprayers. This program is aimed toward anyone spraying small areas (organic or non-organic) who is interested in ensuring they are making the application according to the label rate and getting optimum coverage using backpack other small area spray equipment. Here is a link to the registration form for this workshop. (view PDF)
Gypsy
moth spray window dates
Mike Bryan
Michigan Dept. of Agriculture
Growers should note that the spray window open date for Zone 5 - all other compounds, has been set as May 27. The accompanying chart shows actual and projected open/close dates for application of the two groups of pesticides used for regulatory treatment of gypsy moth in nursery stock and Christmas trees. Always monitor development around your farm as local conditions can affect gypsy moth development.
Table
1. Gypsy moth spray window dates
|
Zone |
Open – Dimilin (150 DD*) |
Open – all other compounds (200 DD) |
Close – Dimilin (700 DD) |
Close – all other compounds (800 DD) |
|
1 |
April 23 |
May 4 |
June 9 (projected) ** |
June 15 (projected) |
|
2 |
April 30 |
May 7 |
June 15 (projected) |
June 20 (projected) |
|
3 |
May 3 |
May 15 |
June 21 (projected) |
June 27 (projected) |
|
4 |
May 15 |
May 21 |
June 28 (projected) |
July 4 (projected) |
|
5 |
May 18 |
May 27 |
July 3 (projected) |
July 11 (projected) |
* DD = Degree Days at base 50 degrees F.
** Projections are based on 30 year historical degree day data.
Jeff
Andresen
Agricultural Meteorology
Geography
The cool front that brought some needed rainfall to many areas of the state Thursday, evening May 24 into Friday morning, will stall just to the south of the state before returning north as a warm front on Saturday. This front will likely linger in the region into next week, setting the stage for an extended period of relatively cool and unsettled weather. Showers and thunderstorms are likely across most areas of the state Saturday into Saturday night, with a continuing chance for showers on Sunday. Monday (Memorial Day) and Tuesday of next week are expected to be cool and dry.
A weather system
approaching from the west will bring yet another chance for rainfall Wednesday
and Thursday. High temperatures will fall back to a range from the upper 50's
north to the upper 70's south during the holiday weekend. Low temperatures will
range from the mid and upper 30's in the far north to the mid 50's south. There
will be the possibility for some scattered frost in interior sections of
Further ahead, medium range forecast guidance suggests the
formation of a ridging feature across western sections of the