Invasive Species

Teasel is endemic to Europe. It was introduced to North America possibly as early as the 1700′s. Teasel has spread rapidly in the last 20-30 years. Teasel grows in open sunny habitats, ranging from wet to dry conditions. Teasel sometimes occurs in high quality prairies, savannas, seeps, and sedge meadows, though roadsides, dumps, and heavily disturbed areas are the most common habitats.

A single plant can produce over 2,000 seeds. Depending on conditions, up to 30-80% of the seeds will germinate, so each plant can produce many offspring. Seeds also can remain viable for at least 2 years. Seeds typically don’t disperse far; most seedlings will be located around the parent plant. Parent plants often provide an optimal nursery site for new teasel plants after the adult dies.

Teasel Identification Teasel grows as a basal rosette for a minimum of one year then sends up a tall flowering stalk and dies after flowering. Common teasel blooms from June through October.  Flowers are small and packed into dense oval-shaped heads. Cut-leaved teasel usually has white flowers, (common teasel usually has purple flowers). During the rosette phase teasel develops a large tap root. The taproot may be over 2 feet long.  Leaves and stems are prickly.

Mowing Mowing will delay flowering, but will not kill the plant – this is a relatively ineffective control technique when used alone.  Teasel will almost always resprout and flower at a lower stature after mowing.

If mowing is conducted after the plant develops seed or after the plant has developed immature flower heads, mowing will assist in the plant’s spread by dispersing the seed.

An early summer mowing (before June 20th) will delay bolting and flower development, but should always be followed by a complete herbicide application.  After mowing areas infested with Teasel, mower should be cleared of all plant debris (on site) and mowers should be cleaned before moving to uninfested areas.

Hand Removal This is a good option for small populations, especially in high quality areas if soil disturbance is minimized.  Rosettes can be spliced 6-8 inches below ground with a spade, which will kill the plant.  Bolting plants can only be killed by hand cutting if the plant is in full bloom.  Cut flower heads off the plant and remove from site.  Splicing the taproot is likely futile, since the root is very large and woody by this growth stage.  Hand cutting stems to 6 inches and spot spraying with Garlon 4 (see amounts under Herbicide) will kill the plant.

Please pull it, or herbicide it with low impact herbicides (but not just before a rain), or mow it with a bagger and dispose carefully (do not compost it!) or even burn it in late Spring (April) if you can do a prescribed burn and have great oak and hickory leaves for fuel. This plant can generate 200 to 3,000 seeds per plant!

It was introduced from Europe in the late 19th century and is killing our oak savanna ecosystem because it steals all the light from other native plants and out competes them immediately. It even poisons the soil in some way so acorns and other native seeds cannot germinate.

Please help us – this year this plant had spread to epidemic proportions. Remove it everywhere! Do not compost the long seed heads, you must dispose of them in garbage bags or burn them or they will still resprout. Control takes three to five years of perseverance but it can be done.

If we all work together to eradicate this beast from our natural areas, our endangered ecosystem will love us and thrive once more (but there are also other invasives to take care of as well – like buckthorn and teasel!) For more, go to MIPN.org (Midwest Invasive Plant Network). Thanks for your help!

Purple Loosestrife colonizes wetland areas (it can produce thousands of seeds per plant!), replacing native species unable to compete for available sunlight, water, and nutrients. Wetlands infested with purple loosestrife lose as much as 50% of their original native plant populations. This limits the variety of food and cover available to birds and may cause the birds to move or disappear from a region altogether.

What is it?  What does it do?  How can I control it?

The moth is a pest introduced from France to Massachusetts in 1869 as part of a silk making experiment.  Some of the moths escaped and have since become major pests which defoliate large tracts of forest.  They have spread across the entire northeast and are now invading northeast Illinois.  Populations peak and then self-collapse, they do massive damage during peak years.

Favorite food: the leaves of any oak tree.  However, the pest is not a fussy eater: it will eat the leaves of more than 500 species of trees.  At high populations, it will defoliate entire forests.  A single season’s defoliation will kill weak deciduous trees, most conifers, and weaken strong deciduous ones.  Multiple years of defoliation will kill even the strongest tree.

Homeowners have an important role in controlling the spread and reducing the populations of gypsy moths.  Protect your valuable trees and reduce the spread of these pests!  If you see these pests in your area, please call the Long Grove Village Hall at 847-634-9440

The non-flying female moth is white with distinctive chevrons (inverted “V”) on its wings.  It lives about 2 weeks during July-August.  During that time it lays eggs in masses containing 50 to 1,500 eggs each.  The egg masses are tan with velvety texture, fading to white as the sun bleaches them. Heavy infestations are obvious.  For homeowners, practical means of stopping the moth starts with these egg masses which are the fall, winter and early spring form of the moth.  Control the pest in September or October by scraping the egg masses off trees and collecting them in a container of rubbing alcohol (do not let them just drop to the ground- they will still survive).   CAUTION: the egg masses are covered with fine hairs which may cause an allergic reaction in some people.  Wear gloves and use a scraper such as a plastic knife to remove them.

Not interested in scraping?  You can use a hand sprayer filled with 50% soybean oil and 50% water (shake frequently).  You can buy this as Golden Natur’l Spray Oil or mix your own.  Spray each mass thoroughly to saturate it.  The oil will suffocate the eggs.

Problem:  Not all egg masses will be on the surface of trees.  They are often semi-hidden under loose bark.  And, the moths will lay them in wood piles, dead branches on the ground, lawn furniture, campers, trailers, etc. SOLUTION:  remove dead branches from the tree and from the ground.  Burn debris piles.  Only buy as much firewood as you will use in one winter (firewood can hide many egg masses). Inspect your outdoor furniture and vehicles, especially if you have been in heavily infested areas (such as Michigan).

ATTACKING THE NEXT PHASE OF THE LIFE CYCLE: CATERPILLAR ROUND UP

Eggs hatch in mid-May.  The caterpillar is recognizable by the blue and red spots and multiple hairs.  This is the destructive phase of the life cycle as the caterpillars feed on the leaves all night long for about 2 months.  During heavy infestations, you can actually hear them eating – and you can hear (and feel) the gentle “rain” of their feces dropping to the ground.  CONTROL at this stage for most homeowners involves “Banding”.  Tie a 6” tall strip of burlap around each tree with twine centered on the burlap.  Fold the top edge over the twine.  Many of the caterpillars crawl down to the ground in the morning and hide in the grass or forest floor litter to avoid predation.  They climb back up in the evening to resume feeding.  The burlap traps them.  You should pick the trapped caterpillars and drop them in rubbing alcohol or otherwise destroy them.  This reduces but does not eliminate the pests, since only the older ones climb down.

Do you have a “forest” to deal with?  If your property is heavily wooded and heavily infested, then spraying may be the most effective control.  The best (safest) spray is “B. t.” (Bacillus thuringiensis), a bacteria known to infect only caterpillars (the larval form of moths and butterflies).   Spraying a mature woodlot requires a plane or helicopter and careful timing of the application.

OTHER CONTROL APPROACHES – USE AN INTEGRATED PEST MANAGEMENT APPROACH

If you are developing your landscape, think DIVERSITY.  Do not plant only one species of tree or woody shrub.  Mix up your plantings. Do not crowd trees close together.

Keep your trees HEALTHY.  They will be much better able to withstand an attack.  Water newly planted trees (trickle of water for an hour each week of the growing season for the first year if there is less than an inch of rain that week).  Remove broken or dead branches.  Consult an arborist if a major specimen looks unhealthy.

Encourage gypsy moth PREDATORS which include, birds (chickadees, blue jays, nuthatches, towhees, robins, blackbirds, starlings, etc.) and mammals (white-footed mice, shrews, chipmunks, and squirrels), parasitic insects (wasps and flies), predatory invertebrates (ground beetles, ants, several species of spiders).  Plant ground cover plants, bushes and fruit trees and build bird houses and bird feeders to provide food and homes for these animals.