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Showing posts from August, 2012

Minnesota's Newest Fruit Pest, the Spotted Wing Drosophila

Bob Koch, Minnesota Department of Agriculture
Jeff Hahn and Eric Burkness, University of Minnesota

A new fruit pest, the spotted wing drosophila (SWD) (Drosophila suzukii), has arrived in Minnesota. This pest feeds on small fruits and stone fruits. The SWD is an invasive pest of Asian origin that was first detected in the continental United States in California in 2008 and has since spread to several western and eastern states. It was found in Minnesota in August, 2012.

The first two detections of this pest were made by members of the public who reported the flies to the Minnesota Department of Agriculture (MDA). First, a homeowner from Hennepin County contacted the MDA about some flies she found in a yeast-baited trap she placed near a raspberry patch. Days later, the MDA was contacted by a citizen who found an abundance of maggots in some wild raspberries picked in Ramsey County. The MDA quickly followed up on both of these reports to visit the sites, collect specimens and confirm th…

Look for fruit rot on pumpkins and squash

M.Grabowski, UMN Extension
Photo 1: Anthracnose fruit rot on winter squash

Michelle Grabowski, UMN Extension Educator

Although most pumpkins and winter squash are not yet ready to harvest. It is important to keep a close eye on the developing fruit. Many different kinds of fungal pathogens can rot winter squash and pumpkins before they are ripe. There are a few things that a gardener can do to prevent wide spread loss.

Weed the pumpkin patch! Weeds crowd growing fruit and create a moist shaded environment that fungal pathogens thrive in. Removing weeds from the garden allows better air flow around the developing fruit. This way the new pumpkins and squash will dry out quickly after rain or irrigation.

Remove any infected squash from the garden. Many fungal fruit rot diseases are easily splashed from one fruit to another on rain or irrigation. If one fruit is infected, the rotted area or the spots on the fruit will produce spores from now until harvest. If left in the garden, the dise…

Summer 2012 Imprelis Update

Kathy Zuzek, UMN Extension Educator, Horticulture

In June, the Office of Indiana State Chemist published the 2012 Imprelis Soil and Vegetation Sampling and Analysis Follow Up Study showing 2011 and 2012 levels of aminocyclopyrachlor, the active ingredient of Imprelis, from 11 sites where Imprelis was applied. The level of aminocyclopyrachlor (ACP) was measured in both soil and vegetation. Soil samples were taken to a depth of 4 inches and were then divided into the top 2" and the bottom 2 inches. Vegetation sampled included dead spruce twigs, willow twigs, and honeylocust twigs and leaves on Imprelis-damaged trees. Levels were widely variable in both 2011 and 2012 across the 11 sites. But on average, ACP levels in the 2012 samples of were 10%, 6%, and 23% of the levels measure in 2011 for the top 2" of soil, the bottom 2" of soil, and the vegetation samples respectively.

What does this information tell us? 1) ACP levels still present in plant tissue are higher than…

Genista Broom Moth

Jeffrey Hahn, Asst. Extension Entomologist

An interesting caterpillar has been found apparently for the first time in Minnesota in several areas of the state. A genista broom moth caterpillar, Uresiphita reversalis, is about one inch long when fully grown. It's a pretty insect with a black head with white markings and a slender yellowish green or mustard colored body. There is a series of black and white colored tubercles (raised spots) running down its body with white hairs coming out of them.


Jeff Hahn
Photo 1: Genista broom moth caterpillar on Baptisia.

When gardeners have discovered this insect in Minnesota, it has been feeding on false indigo, Baptisia. According to BugGuide this caterpillar has also been reported to feed on Acacia, Genista, Lupinus, Texas Mountain Laurel (Sophora secundiflora) and other pea family shrubs as well as Crapemyrtle (Lagerstroemia indica) and honeysuckle (Lonicera spp.).

The adult has a conspicuous snout and holds it wings in a delta shape wh…

August 1, 2012

Cicada Killers

Jeffrey Hahn, Asst. Extension Entomologist



Jeff Hahn
Photo 1: Cicada killer carrying a cicada back to her nest.

There have been many reports of cicada killers, Sphecius speciosus, nesting in yards, gardens, parks, and other areas. These wasps are large, 1 - 1 ½ inches long, with a black and reddish brown thorax, amber colored wings, reddish brown legs, and a black abdomen with yellow bands. They are found nesting in the soil where they prefer, well-drained, light soil exposed to full sun. A cicada killer is a solitary wasp, so you will only find one wasp per burrow. However, they are gregarious, meaning that you can find a number of them in a small area, sometimes establishing large aggregations of nests.

As their name suggests they catch cicadas. Cicadas are stout, winged insects common during the summer. However, people are more likely to hear them as they produce a power line like hum that is heard during the day. Once a cicada killer captures a cicada, she uses her stinger …

Milkweed - Butterfly Magnet - Part I: Brushfoots

Karl Foord - Extension Educator, Horticulture

I was vacationing at Scenic State Park last month, and while driving down the road to Big Fork I saw a patch of common milkweed (Asclepias syriaca) along the roadside (Photo 1). I decided to stop and see if milkweed's reputation as a butterfly magnet was truly deserved.



Karl Foord
Photo 1: Milkweed Patch

I stood in the patch for an hour. It was like being in a natural butterfly house. The amount of activity was amazing. I would estimate there to have been at least 100 butterflies in this approximately 15' x 20' patch. There was also a dizzying array of butterfly species. I have attempted to record this diversity with photographs, and using Larry Weber's Butterflies of the North Woods, have identified 26 different species.

I will divide the findings into three articles; brushfoots, skippers, and a collection of sulphurs, coppers, hairstreaks, and day-flying moths.




Karl Foord
Photo 2: Monarch Adult and Caterpillar



Karl…

Milkweed - Butterfly Magnet - Part II: Skippers

Karl Foord - Extension Educator, Horticulture

This is a continuation of the butterflies encountered in a roadside milkweed patch.



Karl Foord
Photo 1: Peck's and Delaware Skippers



Karl Foord
Photo 2: Silver-spotted and Least Skippers



Karl Foord
Photo 3: Long Dash and Dion Skippers



Karl Foord
Photo 4: Dun Skippers - Male and Female



Karl Foord
Photo 5: Unidentified Skipper

Milkweed - Butterfly Magnet - Part III: Sulphurs, Coppers, Hairstreaks, & Day-flying Moths

Karl Foord - Extension Educator, Horticulture

This is a continuation of the butterflies encountered in a roadside milkweed patch.



Karl Foord
Photo 1: Clouded and Orange Sulphurs



Karl Foord
Photo 2: Pink-edged Sulphur



Karl Foord
Photo 3: Bronze Copper and Acadian Hairstreak Butterflies



Karl Foord
Photo 4: Day-flying Moths

In conclusion, I would have to say that milkweed certainly lives up to its reputation as a butterfly magnet. I am looking for a place to establish a milkweed patch and invite the butterflies.



Deer Flies Common This Year

Jeffrey Hahn, Asst. Extension Entomologist

Deer flies (family Tabanidae) have been particularly bothersome in many areas of Minnesota this year. These flies are about 1/4 - 3/8 inch long and are stout-bodied. They have yellow or black colored bodies with dark colored markings on their wings.


Mark 'Sparky' Stensaas
Photo 1: Typical deer fly. Note the iridescent eyes.


The larvae live in aquatic or semiaquatic areas, like marshy areas, streams and ponds. Adults are found near these breeding grounds, especially along the edge of woodlands but they are strong fliers and can be found miles away from these breeding areas. Watch out for deer flies especially on sunny, calm days. They have a tendency to wait in shady areas for hosts and ambush them as they move past. Deer flies primarily use sight to find a host and seem to be particularly attracted to moving, dark shapes.

They go for the head and neck when biting people. They inflict a painful bite as they use knife-like mo…

Common Blight on Garden Green Beans

Michelle Grabowski, UMN Extension Educator


M. Grabowski, UMN Extension
Photo 1: Common Blight on Bean


Common blight is a bacterial disease of many kinds of bean including green beans, dry beans, and scarlet runner beans. This disease causes large brown blotches that are surrounded by a bright yellow halo on bean leaves. If disease is severe, browning of the leaves can spread, eventually killing the leaf. On bean pods, infections start as round water soaked spots, that become reddish brown with time.

Common blight is caused by the bacteria Xanthomonas campestris pv. phaseoli. Common blight bacteria often first come into the garden on infected seed. Once introduced, it can spread from plant to plant through splashing water or on a gardener's hands and tools. The bacteria can over winter in infected leaves and pods that fall to the ground. Common blight thrives in hot (82-90F) humid weather. The summer of 2012 in Minnesota has provided ideal conditions for the common blight bacteria.

Powdery Mildew on Peonies

Michelle Grabowski, UMN Extension Educator


M.Grabowski, UMN Extension
Photo 1: Powdery Mildew on Peony


If your peonies look like they have been dusted with flour this summer, the likely culprit is powdery mildew. Powdery mildew is a fungal disease caused by Erysiphe polygoni. Several scientists have noted that powdery mildew on peony seems be an emerging problem in landscape plantings in recent years. Although powdery mildew is a common disease problem on garden plants like phlox and bee balm, many gardeners have grown peonies for decades without powdery mildew until recently.

Powdery mildew is unlikely to kill a peony plant. In fact the fungus can only feed on live plant cells. The powdery mildew fungus covers peony leaves and stems with powdery spores and fine fungal strands known as mycellia. Spores are spread from plant to plant on wind currents. In the early stages of infection, powdery mildew colonies look like fluffy snowflakes resting on the leaf surface. these infections quic…

Flowering Plant Video Library - Prairie Plants III

Karl Foord - Extension Educator, Horticulture

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


Wild Bergamot (Monarda fistulosa)




Karl Foord
Photo 1: Wild Bergamot (Monarda fistulosa)

Compass Plant (Silphium laciniatum)




Karl Foord
Photo 2: Compass Plant (Silphium laciniatum)

Rosinweed (Silphium integrifolium)




Karl Foord
Photo 3: Rosinweed (Silphium integrifolium)

Side-oats Grama (Bouteloua curtipendula)




Karl Foord
Photo 4: Side-oats Grama (Bouteloua curtipendula)

Indian Grass (Sorghastrum nutans)




Karl Foord
Photo 5:Indian Grass (Sorghastrum nutans)

Follow up to June 15 article on Swamp Milkweed

Karl Foord - Extension Educator, Horticulture

In the article Swamp Milkweed - Great for Nectar - Bizarre Flowers that appeared in the June 15 Issue of Yard and Garden News, I lamented the fact that I had no pictures of insects carrying the pollinia of milkweed.

Although the pictures in this article are of insects on common milkweed (Asclepias syriaca) and not Swamp Milkweed (Asclepias incarnata) the flowers are similar enough to be applicable.

Please note the pollinia on both a native bee and a fritillary butterfly.




Karl Foord
Photo 1: Milkweed Pollinia taking a ride on a native bee



Karl Foord
Photo 2: Pollinia taking a ride on a Great Spangled Fritillary (Speyeria cybele)