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Showing posts from June, 2012

Brace For Impact: Japanese Beetles Are Coming!

Jeffrey Hahn, Asst. Extension Entomologist

The moment many people have been dreading has arrived - Japanese beetle (JB) are starting emerge. It is not necessary to panic as they are not out in force yet. There have been a few individuals that have been found early (normally JB is not out until the first week of July). However, you know the rest are not too far behind. In fact with the recent rains, we could be seeing large numbers will probably emerge within a week or less.

JB is a pest because the adults feed on the leaves and flowers of many plants while the grubs feed on the roots of turf grass. If you have seen JB grub damage in the past, July is a good time to treat your yard. Use a preventative insecticide, like imidacloprid, after you see adults flying, about late June or early July this year. By the time eggs are laid and grubs hatch, about two to three weeks, the insecticide will be taken up by the grass and the young grubs will be exposed to it.

As the grubs get older they …

Spots, Bands and Browning on Conifers

Michelle Grabowski, UMN Extension Educator



M.Grabowski, UMN Extension
Photo 1: Dothistroma Needle Blight on Mugo Pine


A wide variety of fungal diseases have been reported on pines, spruce and junipers this spring. Fungal needle blights may start out as a spot. As the infection continues the spot grows into a band that completely encircles the needle. Eventually all of the needle tissue beyond the infection dies, resulting in needles that are green at the base and brown at the tip. In other infections, the entire needle or the entire shoot is killed and turns brown.

It is important for gardeners to identify exactly what fungus is causing the problem on their conifer before attempting to control the disease. Each fungus infects different parts of the plant at a specific time of year. Control practices must be precisely timed in order to be effective.


M. Grabowski, UMN Extension
Photo 2: Kabatina Tip Blight on Juniper

The University of Minnesota Extension webpage has an online diagnostic…

Swamp Milkweed - Great for Nectar - Bizarre Flowers

Karl Foord - Extension Educator, Horticulture

Swamp Milkweed (Asclepias incarnata) as you know is an important plant for Monarch Butterflies. The plant also produces significant amounts of nectar and thus attracts a host of other pollinators including various bees and ants (Photo 1).



Karl Foord
Photo 1: Milkweed flower (Asclepias incarnata)






On close examination the flower structure is bizarre. Typical corollas face backward (Photo 1), whereas prominent coronas fold to form a tube of sorts out of which a horn projects toward the center of the flower. The stamens have fused to form a cylinder around the pistil with a pink stigmatic surface in the center (Photo 2).




Karl Foord
Photo 2: Milkweed flower (Asclepias incarnata) close-up of unpollinated flower






Pollen has fused to form wings called pollinia which are connected by a dark pollinarium gland, the whole structure being called a pollinarium. You can see the wings protruding from the side of the fused staminal column (Photo 2). The strat…

Megarhyssa, a Large Ichneumonid Wasp

Jeffrey Hahn, Asst. Extension Entomologist

A large wasp has been noticed in the landscape recently. This insect is a type of ichneumonid (ich-new-MON-id) wasp known as Megarhyssa (meg-a-RISS-uh). Megarhyssa is a reddish brown and yellow insect (another species is black with an orangish head) with a body length of about one and half inches long. That does not include it ovipositor which is another two to three inches long (that's up to over four inches total length!). In addition to the ovipositor, you will find two sheaths protecting it which sometimes gives the appearance that it has three 'tails'. Sometimes Megarhyssa is confused for other large sized insects, e.g. mayflies or dragonflies, so look closely to be sure it correctly identified.



Winnifred Williams
Photo 1: Megarhyssa ovipositing in a tree. Note the long ovipositor

Ichneumonid wasps are parasitic upon other insects. Megarhyssa is a parasite of horntails. Horntails attack dying or recently dead hardwoods…

Plant Video Library - Herbs and Edibles

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture


Rhubarb (Rheum rhabarbarum)



Karl Foord
Photo 1: Rhubarb (Rheum rhabarbarum)








Chives (Allium schoenoprasum)



Karl Foord
Photo 2: Chives (Allium schoenoprasum)









Common Thyme (Thymus vulgaris)



Karl Foord
Photo 3: Common Thyme (Thymus vulgaris)








Horseradish (Armoracia rusticana)

Earwigs: Pests of Homes and Gardens

Jeffrey Hahn, Asst. Extension Entomologist



Jeff Hahn
Photo 1: Earwig found outdoors in garden. Note the second earwig hiding in the crack between the pavers
Earwigs season is beginning as immature nymphs are starting to turn into adults. They are pests when they enter homes, often in large numbers, and become bothersome. They can also damage flowers and other plants in your garden. Earwigs can be challenging to control, especially when they are abundant. Here are some steps you can take to minimize them on your property.

Regardless of whether you are dealing with them in your home or garden, you can reduce their number by using traps in the landscape. Use rolled up newspapers cardboard tubes, or similar objects and set them up outside where you are see earwigs. They will crawl inside these objects by early morning in order to hide. You can then shake them into a pail of soapy water to dispose of them.

Moisture management is also important. Minimize excess moisture by keeping irriga…

June 1, 2012 Issue

In this issue of the Yard and Garden News:

Cold Wet Soils Help Root Rotting Fungi

What Kind of Moth Was That?

Flowering Plant Video Library - Peonies

Fern Leaf Peony (Paeonia tenuifolia 'Little Red Gem')

Tree Peony (Paeonia suffruticosa 'Guardian of the Monastery')

Common Garden Peony (Paeonia lactiflora 'Chalice')

Garden Peony Growing Recommendations

Forest Tent Caterpillars at End of Feeding

Flowering Plant Video Library - Lilacs

Dwarf Korean Lilac (Syringa meyeri)

Miss Kim Korean Lilac (Syringa pubescens subsp. patula 'Miss Kim')

Lilac Fasciation (crested growth form)

Many Types of Lilacs at the Arboretum

Cutworms Gone Wild

Cold Wet Soils Help Root Rotting Fungi

Michelle Grabowski, UMN Extension



H. Schwartz, Colorado State University, Bugwood.org
Photo 1: Onion seedlings suffering from root rot

Although spring came early in Minnesota this year, recent cold wet weather throughout the state is reminding many gardeners that summer is not here just yet. Many perennial plants, trees and shrubs have been leafed out for weeks now. However, gardeners should remember that when starting warm season vegetables from seed in the garden, it is important to wait for soils to warm up. Pumpkin, cucumber and squash seeds like soils that are 65F at a 2 inch depth. Melons prefer soil temps of 70F or above. Sweet corn seeds germinate best when soils are between 55 and 60F. Soil temperatures are measured weekly by the UMN Climatology group at several sites across Minnesota.

Seeds planted into cold soils may sit and wait or may germinate but grow very slowly. In these very early stages of life, seedlings are highly susceptible to soil borne pathogens that cause roo…

What Kind of Moth Was That?

Jeffrey Hahn, Asst. Extension Entomologist



Terry Straub
Photo 1: Hummingbird moth (hummingbird clearwing)
There has been a variety of curiosity questions received recently about interesting moths. Several people have reported seeing hummingbird moths (also called hummingbird clearwing), Hemaris thysbe and/or bumble bee moths (also called snowberry clearwings), H. diffinis, in their gardens. These moths, a type of sphinx moth, are daytime flyers. They have relatively small, stout bodies and their wings are mostly clear, lacking scales on them. They fly like hummingbirds, deftly hovering and flying around flowers as they visit blossoms for nectar. You can distinguish between them as hummingbird moths are little larger with a wingspan of about two inches. They have a yellowish body and the borders and veins of the wings are reddish brown. Bumble bee moths are a little smaller with an average wingspan of about 1 ½ inches. They have a yellow and black body with black veins and a narrow…

Flowering Plant Video Library - Peonies

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Fern Leaf Peony (Paeonia tenuifolia 'Little Red Gem')

Tree Peony (Paeonia suffruticosa 'Guardian of the Monastery')



Karl Foord
Photo 1: Guardian of the Monastery Tree Peony




Karl Foord
Photo 2: Guardian of the Monastery Tree Peony



Common Garden Peony (Paeonia lactiflora 'Chalice')



Karl Foord
Photo 3: Common Garden Peony 'Reward'



Garden Peony Growing Recommendations



Forest Tent Caterpillars at End of Feeding

Jeffrey Hahn, Asst. Extension Entomologist

If you are thinking about treating forest tent caterpillars, check their size because the odds are it is too late to treat them any more this year. If they are between 1 3/4 - 2 inches long, they are either finishing or are done with their feeding. Forest tent caterpillars, sometimes called (incorrectly) armyworms have been active since mid to late April and typically feed 5 - 6 weeks. The best time to treat them is when they are half full grown size, or about one inch long.

Gail Felton
Photo 1: Nuisance forest tent caterpillars crawling on home
Older larvae can cause problems by coming down from trees and wandering around looking for food. Sometimes they can severely damage nearby plants, including those in gardens. Other times, they are annoying when they crawl onto homes, sidewalks, decks, patios, outdoor furniture, and other objects. They may even pupate on homes and other things, further being nuisances.They are difficult to deal with,…