Jeffrey Hahn, Extension Entomologist
Much of Minnesota has experienced consistent rains through the spring and summer this year. This has led to an increase in the numbers of springtails in and around homes and other buildings. Springtails love damp conditions and are typically found in soil, leaf litter, lichen, under bark, decaying plant matter, and other areas of high moisture. Given an opportunity, they will also inhabit your home.
A typical springtail.  Note the furcula, the appendage for
jumping on the tip of the abdomen on the left.  Photo:
Susan Ellis,
What do springtails look like?
Springtails are very small, between 1/16th - 1/8th inch long. They are usually slender insects (there is a group of springtails that is round and stout that is sometimes found in gardens). Most springtails are dark-colored, brown, grey or black although some species are also white, and some are even iridescent and brightly colored
These tiny insects are wingless and cannot fly but they can jump. They use a forked appendage called a furcula (located underneath the abdomen) to propel itself. When not in use, a furcula is tucked up under the body, set like a mouse trap. When it is released, it extends down rapidly sending the springtail forward. A springtail can jump many times its body length.
Why are they found in homes?
Springtails can be found indoors for several reasons. You can find them in areas of high moisture, e.g. around plumbing leaks and damp basements. They can also move indoors in large numbers from the outside when moist conditions exit around the home. Springtails can vary in abundance indoors from just a handful to very large numbers. Fortunately, regardless of their numbers, they are harmless to people and property and are just nuisances.
How can I control springtails?
If you are finding just a small number of springtails occasionally, just ignore them or physically remove them by hand or with vacuum. However, if you are seeing persistent number of springtails they are associated with a moisture problem. The best management is to dry out these areas with a fan or dehumidifier as springtails do not tolerate dry conditions. Also make any structural changes to correct the moisture problem.

While springtails are usually found on the ground, they can
also infest other areas where high moisture exists like roofs
and gutters.  Photo:  Jeff Hahn, Univ. of MN Extension
However, people without moisture problems might still encounter springtails. If they are moving in from the outside, check around the house for damp conditions. This could include rainspouts that do not carry the water far enough away from the foundation, landscapes that slope towards buildings, or excessive irrigation.
 It could even be a moisture problem with the roof or the gutters. Correct moisture conditions to help decrease springtails. As we receive less rainfall, the number of springtails will also naturally go down.
Although it may be tempting to spray a springtail problem with an insecticide, the products available are not very effective against them. Moisture control is the most effective strategy.

For more information see Springtails.
Jeffrey Hahn, Extension Entomologist
Although you can encounter blacklegged ticks (also known as deer ticks) nearly any month of the year, June and July are the times of highest risk for becoming infected with Lyme disease. That is because summer is when the immature nymphs are active. Because of their very small size, it is easier to be bitten and not know it.
Blacklegged (deer) ticks.  Top row: adult male and female.
Bottom row: immature nymphs.  Their small size, especially the
nymphs, makes it more difficult to see them and more likely to be
exposed to Lyme disease. Photo: Jim Occi, Bug Pics,
Additionally, we are in full summer mode, so we are commonly hiking, camping, and doing other outdoor activities that puts us close to where ticks live. Blacklegged ticks are most common in the underbrush of hardwood forests and in fields. Although Lyme disease can occur in many areas of Minnesota, it is most common in the east central, north central and southeast areas of the state.
If you are going to be out in a known tick habitat, take precautions to protect yourself from blacklegged ticks.
* Stay on trails and when possible avoid walking into brushy, grassy areas where ticks are more common.
* Wear long, light colored pants so ticks are easier to detect. For additional protection, tuck your pants into your socks.
* Use repellents to help keep the ticks off of you: Use Deet on clothes and skin but apply products containing permethrin just to clothing.
* Do a tick check when you return from the outdoors. They are small and can be easily overlooked so look carefully! Be sure to look in out of the way places, like behind ears or behind knees.
If you do find a tick, especially if it has been biting, get it positively identified. While blacklegged (deer) ticks can transmit Lyme and other diseases, American dog ticks are not an important disease vectors.
Remember that a blacklegged tick needs to be biting to be able to transmit disease. In fact, it needs to be attached for 24 – 48 hours before it can transmit Lyme disease (the amount time varies for other diseases). Even if you are bitten, not every tick is infected with disease.
A common symptom of Lyme disease, the bullseye rash
(technically called erythema migrans, EM).  Credit: Centers
for Disease Control and Prevention (CDC)
One of the most common symptoms of Lyme disease is a red bulls-eye rash. This occurs in 70-80% of cases. This rash is usually seen 3-30 days after a tick bite. People with Lyme disease may also initially experience fever, headache, and muscle aches.
If you believe you may have Lyme disease, see a physician. When caught early, Lyme disease can be successfully treated with antibiotics.
For more information, see Ticks and their control and Tick-borne diseases in Minnesota.

Now is the time to treat for spruce needle cast diseases. Do you know what’s wrong with your spruce and how to treat it?  

M. Grabowski, UMN Extension Educator
Spruce tree suffering from Rhizosphaera Needle Cast.
M. Grabowski, UMN Extension
Many spruce trees across Minnesota have brown or missing needles along with dead branches. This damage can be caused by a variety of problems including needle cast or needle blight diseases, branch cankers, insect pests, mites, or environmental conditions.
Although management options are available for many of these problems, each problem has its own unique solution. The first step in correcting a spruce problem is getting a correct diagnosis.

Send a sample for diagnosis now

Treatment for Rhizosphaera Needle Cast or Stigmina Needle Cast, two common diseases of spruce trees in Minnesota, need to begin at this time of year. Before you treat you MUST know which disease problem your tree has! Unfortunately it is not possible to diagnose either of these disease problems without a laboratory analysis. Both fungal pathogens cause needles to discolor or fall off. Both fungal pathogens make tiny black spore producing structures along the needle. Although these spore producing structures can be seen with a hand held magnifying glass, it is not possible to distinguish between the two pathogens with a magnifying glass alone.

Where to send a sample

You can send a plant sample to University of Minnesota Plant Disease Clinic on the St. Paul campus. Samples can be dropped off in person or sent in the mail. There is a fee for diagnosis. Check the web page for current prices.

What to send

Send a branch that has live but discolored needles. The branch needs to be long enough to include needles from the past 3 to 4 years of growth. A branch that is 1 to 2 feet long is usually sufficient. This year’s needles will be pale green, soft, and at the very tip of the branch. Previous years needles will be further down the branch with a ring of rough brown bud scales on the twig separating each year of growth. Keep the sample in a cool dry location until it can be sent.
Fill out the online sample submission form and include it with the plant sample.
Bud scales on a spruce twig.
UMN Plant Disease Clinic

A spruce branch with three years of growth.
UMN Plant Disease Clinic

How to send a sample

Wrap the branch in dry newspaper and then plastic before placing it in a box for mailing. It is best to mail the sample early in the week to avoid having the plant sample sit in a storage facility over the weekend. Samples brought directly to the clinic do not need to be packaged.

What happens to plant samples at the clinic?

The plant pathologists at the UMN Plant Disease Clinic carefully inspect every plant sample submitted. Diagnosticians use a variety of techniques to identify the pest or pathogen causing the problem including microscopy, culturing and DNA analysis.
Needle discoloration and loss caused by Stigmina Needle Cast.
M. Grabowski, UMN Extension 

How do I get the results?

The results will be sent to you via email, mail, or fax. You choose by marking a box on the submission form.

Treatment options 

The results will include the name of any pests and pathogens found on the plant sample and information about research based management options available to you. More information about how to treat common spruce diseases can be found at the UMN Extension website.
If you do not want to treat your trees yourself you can hire an arborist. Arborists are tree care professionals that can work with you to provide the best care for trees on your property. 
To find a certified arborist who works in your area, you can use the Find an Arborist tool from the International Society of Arboriculture.

Jeffrey Hahn, Extension Entomologist
Typical carpenter ant.  They are identified by having a one
segmented node and an evenly round thorax when viewed in
profile.  Photo credit: Jeff Hahn, U of MN Extension
Carpenter ants are the most important ant pests found in Minnesota. They can be a problem when they nest in homes and other structures. Because nests are in wood and other hidden areas, it is challenging to know where they are located. Finding the nest and treating it is the best control for carpenter ants.
Always verify that you have carpenter ants. While, people often think of carpenter ants as “big, black ants” (which they are, up to almost ½ inch long), some carpenter ant species are red and black and are smaller, only 3/16th inch long. Some species of field ants, a nuisance species, are black and a similar size to carpenter ants.

Finding carpenter ants in your home in the spring can mean that a nest is present, especially when persistent numbers are found. If you find a swarm of winged carpenter ants indoors, that is a sign of an indoor nest. However, if you find just a few carpenter ant queens (winged or wingless) in your home, they probably just wandered into your home accidentally and no nest is actually present.
A wingless carpenter ant queen.  Finding one or two in your
home (like the author did) is not an indication of a nest
although she is looking to start a nest.  Photo credit:  Jeff
Hahn, Univ. of  Minnesota Extension
If you are having problems with carpenter ants in your home, it is very challenging to eliminate them yourself. For control to be effective, it is necessary to deliver insecticide into the nest to kill the queen and the workers. Killing the foraging workers you see does not impact the nest.
Baits can be effective for some ant problems. However, the ant baits available to residents are not sufficiently attractive or effective to successfully eliminate a carpenter ant nest.
The best control for carpenter ants is to contact a licensed pest management service to treat the nest. An inspection is important to find the foraging trails and if possible the nest(s).
There are several options for treating the nest. Many technicians use a non-repellant residual insecticide, such as Termidor, sprayed around the building’s exterior. The carpenter ants pick up the residue and take it back it to the nest where it gets spread through colony, ultimately eliminating it.
Technicians may also set out baits to control carpenter ants. They have access to a variety of baits and have the experience to use them. It is not unusual for technicians to use more than one bait to be successful. Remember that baits take time so be patient and allow carpenter ants to take enough back to control the nest.
Carpenter ants tunnel and nest in wood.  Control them to
prevent damage to your home.  Photo credit: Jeff Hahn,
Univ. of MN Extension
If the exact location of the nest is discovered, it can be treated directly with a dust. This may require drilling into walls or injecting dust through outlets.
Once treatment has been applied, a technician needs to evaluate how successful the initial control was and whether any additional steps are needed.
However, treating the entire house multiple times on a scheduled basis is considered excessive and less effective. Treatment should be targeted and as specific as possible.
For additional information, see Carpenter ants.
M. Grabowski, UMN Extension
Apple scab at mid summer
M. Grabowski, UMN Extension 

Two common leaf spot diseases that blight Minnesota landscapes every year are tar spot of maple and scab of apple and crabapple. Both diseases are caused by fungi that survive winter on last year’s infected leaves.
As snow melts and tree buds begin to swell, gardeners have one last chance to remove these infected leaves before the fungal pathogens become active.

How do leaves become infected?

Both fungi produce new spores in response to warming temperatures and moist conditions created by snow melt and spring rain. Spores are ejected forcibly into the air where they are carried by wind to new emerging leaves. There they will initiate this year’s leaf spot epidemic.


Although neither disease is a significant threat to the health of the tree, leaf spot diseases blight the appearance of landscape trees, reducing their value as ornamentals. Many gardeners look for management options late summer when symptoms are very obvious but it is too late to prevent disease.
Apple scab infected crabapple leaves
Photo: M. Grabowski, UMN Extension 

Apple scab

Task: Rake up and remove any remaining leaves that may have been infected with apple scab last year. Bury infected leaves in a backyard compost pile or take them to a municipal yard waste site.
Deadline: Before tree buds open and ¼ inch of green leaves can be seen emerging.

Tar Spot

Task: Rake up and remove any remaining leaves that may have been infected with tar spot last year.  

Bury infected leaves in a backyard compost pile or take them to a municipal yard waste site.

Deadline: Before new leaves reach full size.

Maple leaf debris with tar spot
Photo: M. Grabowski, UMN Extension
Michelle Grabowski, UMN Extension Educator
It is now the high risk period for oak wilt in Minnesota. Gardeners in the area of the state where oak wilt occurs should not prune oaks until next fall. Oak wilt is a fatal disease that can affect all oak trees. Red oaks can wilt and die in as little as 4 weeks. White oaks often slowly decline over several years. Protecting trees from wounds and pruning cuts during the high risk period is critical in preventing new oak wilt infections.
An oak wilt spore mat revealed
below the bark of an infected
oak. M. Grabowski
UMN extension
At this time of year the oak wilt fungus produces a spore mat with sticky fruity smelling spores that attract sap beetles. The spores stick to the sap beetles' bodies when they visit the spore mat. Sap beetles are also attracted to the sap from fresh pruning cuts or wounds. If the beetle visits a recently pruned oak tree after visiting a spore mat, the tree can become infected.
The good news is sap beetles can not infect an oak tree without a wound. Bark is the best protection. If an oak tree must be pruned during the high risk period, the surface of the pruning cut should be immediately covered with water based paint or shellac. The safe period for pruning oaks typically occurs from November through March. If you missed this years safe pruning period, mark your calendar and wait until the next safe pruning period begins in November.

It's tick season!

Written by
Published in Minnesota Gardening
Jeffrey Hahn, Extension Entomologist
We have waited patiently (or in some cases impatiently) for the arrival of spring. Now that it is here, we can’t wait to get outside and enjoy the nice weather. Keep in mind that with the warm weather also comes ticks. With a few precautions, you can still enjoy the outdoors without worrying about them.
Adult female American dog tick (wood tick) is not an
important disease vector. Photo: Jeff Hahn, UMN Extension
There are two common ticks in Minnesota; the blacklegged tick (also called deer tick) and the American dog tick (also called wood tick). Both ticks are nuisances because they bite to feed on our blood as well as the blood of our pets, including dogs and horses.
However, blacklegged (deer) ticks are a health problem because they are a potential vector of Lyme disease and other diseases (see Tick-borne disease in Minnesota). Both of these ticks are common in grassy fields and the underbrush of hardwood forests.
Keeping ticks out of your yard is challenging, especially when property is adjacent to natural habitat. Fortunately ticks generally are not found in lawns that are kept short. Routinely mowing brushy areas along the perimeter of lawns will help minimize ticks from moving into yards.
If large numbers of ticks are present, it is possible to treat the perimeter with an insecticide to help reduce the number that may move into that area. However, it is not practical or effective to treat an entire area of natural control ticks.
Regardless of what you do on your property, use personal protection when you are in known tick areas, i.e. fields and wooded areas. Take these steps to protect yourself from ticks:  
  • Stay on trails and avoid when possible walking into brushy, grassy areas where ticks are more common.
  • Wear long, light colored pants so ticks are easier to detect. For additional protection, tuck your pants into your socks.
  • Use repellants: Deet can be treated on clothes and skin while products containing permethrin are applied just to clothing
  • Do a tick check when you return from the outdoors. They are small and can be easily overlooked so look carefully. Be sure to look in out of the way places, like behind ears or behind knees.
If you do find a tick, especially if it has been biting, get it positively identified. While American dog ticks are not an important disease vectors, blacklegged (deer) ticks can transmit a variety of diseases, especially Lyme disease. For more information, see Ticks and their control.
M. Grabowski, UMN Extension Educator
Fresh pruning cuts on an oak tree.
M.Grabowski, UMN Extension 
If you have oaks in your landscape that need pruning and you live in an area of Minnesota where oak wilt occurs, pruning must be done before the oak wilt fungus and it's insect vector become active. Oak wilt is a fatal disease of oak trees that can be found in some counties of Minnesota. If you live in an area where oak wilt occurs, it is critical to prune oak trees before the high risk infection period begins in April. The risk status for oak wilt is updated as weather conditions change, but in a normal year high risk of oak wilt infection occurs in April, May, and June. Check in with My MN Woods to find the current oak wilt risk status before you prune.
Oak wilt has been found within
20 miles of all areas colored pink
Oak wilt is caused by a fungal plant pathogen. Spores of the oak wilt fungus are carried by sap feeding beetles in the Nitidulidae family. These small beetles are attracted to wounds and fresh cuts on oak trees. When they arrive at the cut branch, spores of the oak wilt fungus are knocked off and can infect the open wound.
Red oak trees are highly susceptible to oak wilt and can wilt and die in as little as 4 weeks after infection. Once infected with oak wilt, there is no way to save a red oak tree. White and bur oaks can also become infected with oak wilt. These trees are able to slow the infection but will eventually succumb to the disease in a few years. Some treatment options are available for white and bur oak trees if the disease is identified at the early stages.
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