Landscape and nursery
§ Japanese beetles will be active for another four to six weeks
§ Fall webworm control
§ Drainage problems in landscapes
§ Nickel in plant nutrition
Turfgrass
§ Watch for chinch bug and bluegrass billbug damage in the next two weeks
§ Extreme conditions prove too much for preemergence herbicides
Christmas trees and forestry
§ Christmas tree insect update: scales, mites and midges
§ Lophodermium needlecast
Around the home
§ Marauding springtails
§ Bark cattle roaming the range
§ European paper wasp update
In some places, linden trees, pin oaks, purple leaf plum, roses, grapes, raspberries and many other trees, shrubs and flowers have been stripped from Japanese beetle feeding, leaving lace-like leaves with just the veins intact.
This is a good year for Japanese beetle because last July and August we had frequent rain that kept lawns green. This means the grubs survived real well last year. Japanese beetle grubs do not survive well if lawns are droughty in July and August. But because last summer lawns were moist, we had excellent survival and a bumper crop of beetles emerging now.
For plants susceptible to defoliation, like linden and roses, you can spray them with Sevin, Tempo or Discus to prevent more feeding damage. In heavily infested areas, you may have to spray once every week or two. Homeowners can use Sevin or Bayer Multi Insect Killer. Expect the beetles to remain active until early September this year.
Watch for webs to appear on the branch tips of walnuts, crabapples and a few other types of trees that fall webworms love. Remove the webs by pruning whenever possible, or spray the branches around the webs with an insecticide to kill the caterpillars before the webs become larger.
Fall webworms don’t usually cause enough defoliation to hurt the trees, but the webbing can be unsightly. Bacillus thuringiensis products provide a good alternative to conventional insecticides for fall webworm and other caterpillars.
In evaluating landscape problems around the mid-Michigan region, inadequate soil drainage is one of the most common issues I encounter. I recently received a call from a site manager in southwest Lansing who reported that a large proportion of the boxwoods planted in his landscape last fall were dead or dying. Before visiting the site, I suggested that the manager dig a few of the plants to inspect the roots to see if the plants were showing signs of becoming established. When I visited the site the next week, the problem was obvious. All of the holes where the plants were dug were filled with water to within three inches of the soil surface. Clearly, the drainage on the site was inadequate for anything but the most flood-tolerant plants. Unfortunately, the most realistic solution – installing drain tile – will be more difficult and expensive then if it had been installed before the irrigation system and landscape plants were established.
Plants need water. So why is too much water such an issue? In addition to water, plant roots also need oxygen. If the pore spaces in the soil are filled with water, roots are not able to respire and therefore unable to grow or take up water and nutrients. This why some symptoms of excessive water are similar to symptoms of drought or nutrient deficiencies. Excessively wet soil can also lead to problems with root rot pathogens.
Excessively wet soils may be caused by one or a combination of several factors.
Lack of surface drainage. This refers to the inability of run-off water to leave the site. Surface grading may eliminate the problem. As a general rule a slope of at least 2% (2’ drop per 100’ of length) should be provided to ensure runoff.
Impervious layers. Even though the soil near the surface may be coarse and permit infiltration, clay layers or hard pans may limit drainage into the subsoil. The remedy may be to break up the plow pan by sub-soiling, which breaks up the plow pan. However, sub-surface hard pans can re-form over time and drain tiles may still be the best long-term solution.
High water table. In some cases, saturated soils cannot be avoided due to the response of a high water table rather than inadequate surface drainage. Sub-surface drainage can eliminate the problem, but another long-term solution is to select wetland plants adapted to wet conditions.
For more information visit:
http://grounds-mag.com/ar/grounds_maintenance_drainage_solutions/
Pneumonics are a great device for
memorizing information. In fact, sometimes it’s amazing how well they work. Over
25 years ago, I learned the essential elements for plant growth in Mr. Rackowicz’s Intro Botany class at
As with most things in science, however, some of the views we learned growing up don’t tell the whole story anymore. I remember learning in grade school that Jupiter has 12 moons. I think the latest count is 40-something. Recent advances are also changing our view of plant nutrition. The list of 16 elements deemed to be essential was based on research that showed plants could not complete their life cycle without them. Researchers are learning, however, that some elements, nickel and silicon, are beneficial for plant growth.
Nickel, in particular, has received attention recently. USDA scientists report that Ni deficiency results in a condition known as “mouse ear” (curling of leaf margins) in pecan orchards. Moreover, the researchers at the Southeastern Fruit and Tree Nut Research laboratory found that the deficiency could be corrected with foliar application of Ni fertilizer. As with most micronutrients, Ni is not usually considered limiting in normal field growing conditions. However, Ni deficiency may occur in soils with adequate Ni due to competitive uptake of other metal elements such as magnesium, iron, copper and zinc. The researchers observed that Ni deficiency was often induced by excessive accumulation of other metals due to long-term fertilization. Ni deficiency is also referred to as “little leaf disease” and may occur in river birch, plum, peach, walnut and grapes. If you suspect a Ni problem with your crop, the usual rules for diagnoses still apply: note visible symptoms, consider other causes (stress, insects, pathogens), get a soil test, run a foliar analysis. Since we don’t have a lot of comparative data on Ni levels in ornamentals, the most useful analysis is to collect separate soil and foliar samples from “good” and “bad” samples. Then these results can be compared side by side to gain insights into the cause of the nutrient imbalance.
Chinch bug damage will appear as drought damage to the sunniest areas of the lawn. Examine the thatch and soil surface carefully for the tiny 1/8 inch long black chinch bugs with white markings on the wings.
More than 15 bugs in two minutes of searching means you have enough to cause some turf injury. Spot-spray infested parts of lawn with Talstar, Tempo, DeltaGard, Scimitar or Sevin.
Homeowners can use the Multi-Insect Killer.
For billbugs grab a pinch of turf from around a damaged area
and pull it up. Examine the base for hollow stems and sawdust-like frass. The 3/8 inch long legless grubs may also be present.
Spot-treat infested areas with Sevin at the grub
rate.
Make a space on the trophy shelf – 2005 will go down as a
banner crabgrass year. In what is shaping up to be one of the hottest summers
in 100 years, the weeds are “making hay while the sun shines.” Calls coming in
from all over the state are reporting very heavy crabgrass infestations. Lawncare operators who are accustomed to
Preemergence application timing for crabgrass can usually be made between April 15 and May 15. Most lawncare companies will err on the early side because of the reliable medium and long-residual products available. Long residual preemergence products (Dimension and Barricade) providing eight to 10 weeks of control should be just fine if crabgrass germination tails off by mid-June. Timing is somewhat more critical for medium residual products (Team Pro and Pendulum) that typically last six to eight weeks. Eighty to 90 percent of crabgrass germination occurs when adequate moisture is present and soil temperatures are between 60 and 70 degrees F at zero to two inches depth (Figure 1).
In May only the moisture requirement was not met. As a
result, the crabgrass did not germinate in mid- to late May, as it sometimes
will, and the turf ended the month in a significantly stressed state. In
addition, the above normal temperatures combined with the heavy, sporadic
rainfall events of June and July have been a boon for weed development (Figure 2). Think
of this year as the 100-year flood event, only for weeds. Large and smooth
crabgrass, white clover, chicory, buckhorn plantain and wild carrot are out in
record numbers. Most new establishments from this spring are completely overrun
with weeds (photos). If the weeds haven’t suffocated those tender new turf stands,
diseases such as pythium and brown patch probably
have.
It is impossible to predict a late germinating crabgrass
year. Even applicators that properly timed their preemergence
applications based on soil temperatures are likely to have breaks this year due
to the lack of moisture and thin turf that occurred in May. The result is that
many (properly timed) preemergence applications did
not prove effective. Crabgrass and customer callbacks abound and postemergence products are flying off the shelves. See MSU
Extension bulletin E02TURF “Crabgrass Control in Home Lawns” for specific
management and herbicide recommendations.
Growers should still
be checking for scale crawler activity, especially with pine tortoise scale.
This is also a good time to evaluate how effective your pesticide application
was. Look for areas you may have missed. Ask yourself were there any patterns –
did you get good coverage on all parts of the tree, were there any tree shadow
areas? Then look at your spray equipment to see what modifications you need to
make – check for worn nozzles, increase the amount of water per acre, slow
down, spray in different direction, raise or lower sprayer height, add extra
nozzles, etc.
We continue to find spruce spider
mite on Fraser fir. Growers should still be scouting for these. Pay particular
attention to the trees you plan to harvest this year. Check for mite activity
by closely inspecting the older needles near the tree stem or by sharply
rapping shoots over white cardboard or a notebook with white paper.
The yellow banding from Douglas fir needle
midge is becoming more noticeable. I recently looked at a field where the tops
of the trees where yellow from this pest. This midge is relatively new to
Pictures of the
Douglas fir needle midge can be found in the September 5,
2003, Landscape Alert.
Management of this needlecast disease of Scotch and red pine is slightly
different than the needlecast diseases found on
Douglas fir and spruce we have written about in other issues. This disease can
kill red pine seedlings and causes browning on Scotch pines in the spring.
Scotch pines with needles showing brown spots with yellow margins, yellow
needles or brown needles, especially at the bottom of the tree are probably
infected with Lophodermium seditiosum.
The dead needles
will fall off the trees in June, July and August, and these dead needles will
continue to support fungal reproduction by allowing the fruiting bodies to
develop and the spores to disseminate throughout the trees. Trees look as if
they are making a comeback since the new buds break with a green flush;
however, these new needles will become infected from August to October from the
spores issuing from the fruiting bodies on the dead needles. The fungus will
stay in those healthy looking needles all winter until spring, when, again,
those needles will begin the process of yellowing, browning and dropping off.
Even though we see
the symptoms of Lophodermium in the spring, the most
important time to protect trees is in late July throughout the summer and fall
especially if these months are warm and moist. Apply a registered, preventative
fungicide three or four times, once every two to three weeks from late July
through October. Plant long-needle Scotch pines, which are
more resistant such as those from
We are getting lots of calls and samples of springtails this summer from people who are finding large numbers of them in their homes. Springtails are minute, primitive insects that can occur in enormous numbers (50,000 per cubic foot) in forest litter and organic soils (photos). Springtails can be found outdoors in any moist situation, usually feeding on algae, fungi and decaying vegetation. We think this invasive behavior is the result of our hot, dry summer.
Springtails (Order Collembola) are extremely sensitive to moisture. If their normal environment becomes dry, they will actively seek moisture, sometimes invading homes and similar structures. They are most commonly found in walk-out basements, kitchens and bathrooms. These harmless insects are not known to bite or cause damage to stored food, wood or fabrics. Springtails can persist indoors if adequate moisture is found and if fungi, mildew or decaying vegetable matter exist in sufficient quantities, but in general, they are only occasional or incidental visitors in structures.
If springtails persist indoors, the best control is to decrease the humidity and remove anything found to be moldy or in a state of decay. Household aerosol insecticides or persistent insecticides can be used indoors to control them. Treating the exterior walls and foundations with a persistent insecticide registered for this use may aid in preventing their entry.
There are nearly 700 species of springtails in the
Lots of people have been calling us and sending in specimens of another odd-looking insect they are finding in large groups on the bark of their shade trees. These strange bugs are known as giant barklice (Order Psocoptera) or more aptly as bark cattle because they form large congregations or herds and move en masse across the tree bark (photos).
These bark lice are
among the biggest of their kind in
Bark cattle feed on molds, fungi, pollen, fragments of dead insects and other detritus. None of the barklice is capable of injuring plants. Since they do not harm the tree, no control measures are needed.
It looks to be another great summer for the European paper wasp. We are finding numerous nests around our yards, and the nests are getting bigger with 30 or more workers tending a single nest. They are getting less and less tolerant to anyone who disturbs them. All this mean is that it is time to start carrying a can of wasp killer (the kind that shoots a stream of juice 15 feet or so) whenever we venture out into our yards.
This wasp will build a nest practically anywhere that offers the slightest protection from the rain. Common nesting sites include bird feeders and nest boxes, under “in-use” covers on outdoor electrical outlets, beneath mailboxes, beneath steps and deck.
Get them now before they get you. Shoot fast and shoot
straight,