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Showing posts from June, 2014

Squash Vine Borers are Out Now

Jeffrey Hahn, Extension Entomologist

Jeff Hahn, Univ. of MN Extension
Photo 1: Mating squash vine borer adults

Squash vine borer adults have just been sighted. If you are growing summer squash, winter squash, or pumpkins, take the proper precautions to protect your vine crops from this insect. This garden pest less frequently attacks butternut squash, cucumbers and melons. If you are unsure whether squash vine borers are in your area, monitor your garden for their presence.

Set out a yellow pan of water. Yellow is attractive to squash vine bores, and they will fly to and fall into the water. Check these traps at least once a day. Squash vine borer adults are easy to recognize as they are wasp-like and about ½ inch long. They have an orange abdomen with black spots and the first pair of wings is metallic green while the back pair of wings is clear. These moths are active during the daytime and you may also observe them when you are in your garden.

Management of squash vine bo…

Don't be Fooled by Fungus Killed Flies

Dori Eder
Photo 1: Fungus killed flies on grape. Despite any circumstantial evidence, they are incapable of damaging plants.

People are finding a curious insect in their gardens and yards now. Grayish black flies, about ¼ inch long, are being found clinging to the leaves and stems of a variety of different plants. Their legs and wings are typically splayed out in odd, unnatural positions. If you watch the fly carefully, you will notice it doesn't move. That's because it's dead - it has been killed by a fungus that is specific to these flies.

This fungus has been particularly common this year due to the abundant rainfall we have experienced throughout much of Minnesota. When seed corn maggot flies become infected with this fungal disease, they usually fly to a plant or other object and climb up. Eventually they die, leaving their legs and wings in whatever position they were in at the time of death. Additionally, their mouthparts are often extended out. In recentl…

Blossom blight blasts crabapple blossoms

Michelle Grabowski, UMN Extension Educator

M. Grabowski, UMN Extension
Photo 1: Brown blossoms and leaves infected with fire blight clinging to a crabapple tree
This June, many gardeners were surprised to see the blossoms on their crabapple trees turn brown and shrivel along with the leaves growing alongside them. In many cases blossoms and leaves became discolored all along several branches (Photo 1). In other cases individual clusters were affected. A month later, these brown blossoms and leaves remain attached to the tree and are likely to stay through the growing season. These unattractive brown clumps of foliage not only affect the beauty of the tree but have a significant impact on the progression of the disease.

These unusual symptoms are caused by the disease fire blight. Fire blight is caused by the bacteria Erwinia amylovora, and it affects trees and shrubs in the Rosaceae family. Fire blight can often be found on crabapple, apple and mountain-ash in Minnesota. Serviceberry,…

Rose Chafers are Here

Cindy Schmid
Photo 1: Rose chafers on peony flowers.

Rose chafers are out in full force right now. If you live in an area with sandy soil, you are much more likely to see them in your garden. These scarab beetles feed on a variety of plants but are particularly interested in the flowers of roses and peonies. They can also feed on the leaves of a variety of plants. Rose chafers feed for about three to four weeks; we can expect to see them into early July. There are several options for dealing with this beetle including handpicking and the judicious use of insecticides. For more information, see Rose Chafers.

Start Trapping for Spotted Wing Drosophila

If you grow raspberries, strawberries, cherries, blueberries, or other susceptible soft-skinned fruit, start a trapping program to monitor the potential presence of spotted wing Drosophila (SWD). A single SWD has been detected on June 6 in a trap set on the University of Minnesota St. Paul campus. Last year, the first SWD was trapped on June 27. It is safe to assume that SWD are present throughout the state.

Jeff Hahn, Univ. of MN Extension
Photo 1: Use traps to detect spotted wing Drosophila's presence.

Home gardeners can monitor SWD with homemade traps. Use a large plastic cup with a cover and make several 3/16th inch diameter holes near the top. Put one to two inches of apple cider vinegar into the cup. Add either a yellow sticky card slightly above the vinegar or a little bit of liquid soap, such as dish soap. Hang traps on branches in a shaded location near fruit. Check traps at least once a week, replacing the sticky card (if used) and apple cider vinegar bait. Disp…

Two Early Flowering Plants for Bees

Karl Foord, Extension Educator - Horticulture

Karl Foord
Photo 1: Andrenid bee approaching Golden Alexander's flower

Karl Foord
Photo 2: Andrenid bee on Golden Alexander's flower

Karl Foord
Photo 3: Two different Andrenid species on Golden Alexander's

Karl Foord
Photo 4: Bombus griseocollis on Blue False Indigo

Karl Foord
Photo 5: Bombus griseocollis on Baptisia australis

Karl Foord
Photo 6: Brown-belted Bumble Bee queen on Blue False Indigo

One of the keys to have a great pollinator garden is to have different types of flowers available for the pollinators at different times of the year. Two early flowering favorites of mine are Golden Alexanders (Zizia aurea) and Blue False Indigo (Baptisia australis).

Golden Alexander's flowers are shallow and easily accessed by small bees with short tongues such as the Mining Bees (Andrenid spp.) shown in photos 1 - 3.

Blue False Indigo flowers are much more difficult to access by small bees but are easily accessed and preferred by…

Protect your Apples from Plum Curculio - Now!

Karl Foord, Extension Educator - Horticulture

Karl Foord
Photo 1: Plum Curculio feeding on young apple

Karl Foord
Photo 2: Plum Curculio feeding on young apple fruit

Karl Foord
Photo 3: Plum Curculio feeding hole

Karl Foord
Photo 4: Apple Maggot Barrier protecting young apple fruit from Plum Curculio

The Plum Curculio (Conotrachelus nenuphar) is a pest that may be active now in your apple trees (Photo 1). The first damage caused by these insects is feeding (Photo 2) which creates a small hole (Photo 3). Although this hole is shallow (usually less than 1/8th of an inch, multiple such wounds can affect the quality of the fruit. One way to avoid this type of injury is to place nylon stocking maggot barriers on the fruit (Photo 4). See "A Different Way to Protect your Apples from Apple Maggot". Soon these beetles will mate and you will begin to see a different type of damage caused by the female cutting a crescent -shaped slit into which she will deposit her eggs. See photo 3…

Cabbageworms are Active Now

Jeff Hahn, Univ. of MN Ext
Photo 1: Watch for cabbageworms on your cole crops.

Are you growing any cole crops, such as cabbage, broccoli, kale, radish, or turnip, in your garden? If you are, it's a good idea to check them out for imported cabbageworms. As an adult, imported cabbageworms are pretty white butterflies. As a caterpillar these larvae are light green with thin yellow stripes running down their body; a series of short hairs gives it a velvety appearance. It's the caterpillar stage that damages plants by chewing holes in the leaves, sometimes seriously defoliating them.

These crops can tolerate some feeding. However young seedlings and transplants are particularly susceptible to feeding injury and should be protected. Checking plants regularly is very important so any infestations can be spotted quickly to minimize injury. If any imported cabbageworms (and cabbage loopers later in the summer) are discovered, there are several options for dealing with them, i…

Don't Confuse Six-spotted Tiger Beetles with EAB

Jeffrey Hahn, Extension Entomologist

Jeff Hahn, Univ. of MN Extension
Photo 1: Six-spotted tiger beetle, a common insect in May and June.

The six-spotted tiger beetle is a native insect found throughout most of Minnesota commonly in deciduous forests, along the edges of woods, and in adjacent fields. It can even be found in urban areas in yards and gardens. Watch for this beetle at or near the ground in areas where the sun shines.

This beetle measures about ½ inch in length. It really stands out because it is an iridescent green or blue-green. It also has six white spots, although that number can vary. The six-spotted tiger beetle has conspicuous sickle-shaped mandibles (jaws) and large bulging eyes on the side of its head.

The six-spotted tiger beetle is present in Minnesota from May into early July. It is very active, moving rapidly in short bursts. It is common to see it run rapidly or fly a short distance. As one might suspect from the large eyes and the powerful jaws, th…

Damaged Lawns: Steps to Bringing Some Life Back

Sam Bauer, UMN Extension- Turfgrass Science

Spring Damage
The grass-growing season is in full swing, and for some of you this means repairing turfgrass areas that were impacted by winter injury. By now, it should be apparent which areas of your lawn were damaged (but not killed) from winter stresses and which areas will not recover from winter injury. Plants that are slowly recovering, suffered damage only to the leaves and are able to produce new leaves during the spring. Practices such as removing dead leaf tissue and fertilizing will help expedite the recovery of these areas. In contrast, plants that are dead suffered damage to the crown tissue (survival organ of turfgrasses) and will need to be renovated and repaired. The goal of this post is to provide you with information on the different types of winter stresses that effect turfgrass plants and the cultural practices that can be used to minimize winter injury. In addition, a step-by-step outline of the recovery/renovatio…

June 1st Issue of Yard and Garden News

Andrenid Bees - Critical Pollinators of Apples, Blueberries, & Raspberries

Karl Foord, Extension Educator - Horticulture

Karl Foord
Photo 1: Andrenid Bee on Willow Flower

Karl Foord
Photo 2: Andrenid Bee on Prunus flower

Karl Foord
Photo 3: Andrenid Bee on apple flower

Karl Foord
Photo 4: Andrenid Bee and blueberry flowers

Karl Foord
Photo 5: Andrenid bees on raspberry flowers

Andrenid bees are one of the earliest emerging bees in the spring. You can see them on willow flowers depending on the type of spring (Photo 1), and we had such a spring this year. Following willows the Andrenids will often be found on Prunus species (plums & cherries) (Photo 2). The next trees and shrubs to flower are apples (Photo 3), blueberries (Photo 4), and raspberries (Photo 5). Andrenid bees are important native pollinators of these species. The next time you put blueberries on your breakfast cereal or make raspberry jam, remember that Andrenid bees have played a significant role in the creation of those fruits.

Honey bees enjoying a drink on a hot day

Karl Foord, Extension Educator - Horticulture

Karl Foord
Photo 1: Honey bee watering hole

Karl Foord
Photo 2: Honey bees hovering around watering hole

Karl Foord
Photo 3: Honey bees hovering around watering hole

Karl Foord
Photo 4: Honey bee hovering while drinking

Karl Foord
Photo 5: Honey bee drinking on edge of puddle

If you think back to last Friday May 30 2014, it was a hot day with temperatures in the high 80's. I was observing pollinators in the apple trees at Pine Tree Apple Orchard. They were draining a low area of one of the fields and in the process created a puddle (Photo 1) just across the field road from a number of honeybee hives. This was a perfect opportunity for the bees to gather around the watering hole, if you will. The bees would hover around the hole looking for a good place to land without getting wet (Photos 2 & 3). One honeybee hovered while she drank (Photo 4), but all the others landed prior to drinking (Photo 5).

Where's the Redbud Bloom?

Over the past 30 years, Minnesotans have enjoyed many mild winters. But the winter of 2013-2014 was a return to the winters of yore. In many parts of the state, the past winter was the coldest in either 35 or 78 years and it is a winter that will be remembered for long persistent periods of very cold temperatures. The persistent cold allowed deeper than normal frost penetration in soils even though snowfall was heavy and just as persistent as the cold temperatures. No matter what statistics you look at - lowest temperatures recorded in the state, average monthly temperature, number of days Minnesota reported the coldest temperature in the nation, amount and persistence of snow cover, soil frost depth, windchill conditions, number of nights with 0 degrees or lower - they all add up to one long, cold, snowy, difficult-to-live-through winter.

The past winter also took its toll on trees and shrubs. Winter burn on evergreens and salt damage on roadside white pines were severe. With…