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Hollyhock Rust at its Worst

M. Grabowski, UMN Extension

Photo 1: Hollyhock rust on leaves

Michelle Grabowski, UMN Extension Educator


Frequent rains this spring and early summer have created favorable conditions for hollyhock rust. Hollyhock rust is caused by the fungal pathogen Puccinia malvacearum, which infects hollyhocks and related weeds like roundleaf mallow (Malva neglecta).

Early symptoms of hollyhock rust are easily missed. Small waxy yellow bumps form on the lower surface of the lower leaves of the plant. With age, these pustules turn reddish brown and a bright orange spot develops on the upper leaf surface. In wet years, spores from these early infections easily spread to infect leaves, stems, petioles and even flower bracts. Heavily infected leaves turn yellow and may wither and curl. This significantly reduces the plant's ability to do photosynthesis. The hollyhock rust fungi can survive from one season to the next in infected live crowns, as spores in infected plant debris, or on seed from infected plants.

M. Grabowski, UMN Extension

Photo 2: Hollyhock rust on stem and flower bracts

Unfortunately it is too late to prevent hollyhock rust this season. Keep plants as dry as possible by avoiding sprinkler irrigation and pulling weeds to improve air circulation around the plants. This will help to reduce spread of existing infections. Gardeners with infected plants should cut off the plant at ground level after flowering is complete. Infected plant material should be removed from the garden and buried, placed in a compost pile that heats up or taken to a municipal compost facility. Next year, mulch around the base of the plant to reduce the spread of spores from plant debris. Scout plants in early spring. Look for yellow waxy pustules on the lower leaf surface. Infected leaves should be removed and buried or composted.

Diseases in the Vegetable Garden

Michelle Grabowski, UMN Extension Educator



M. Grabowski, UMN Extension


Photo 1: Black rot is a bacterial disease of broccoli, cabbage, cauliflower and other brassicas.


This years frequent rains have created ideal conditions for many fungal and bacterial diseases in the vegetable garden. These pathogens need moisture to reproduce, spread and start new infections. Although gardeners can't change the weather, a few things can be done help plants dry out after rain or dew and to reduce the spread of disease.

1. Space plants to allow for air movement around the plants and through the foliage. Dense planting results in fruit and foliage that stay wet longer; a favorable condition for many pathogens.

2. Pull weeds. Weeds crowd the vegetable plant, steal nutrients and reduce air movement in the garden.

3. Completely mulch the soil with landscape fabric, plastic mulch, straw or wood chips. Many pathogens survive in plant debris and soil. Rain and irrigation splash water, soil and pathogens onto the lower



M. Grabowski, UMN Extension


Photo 2: Angular leaf spot on cucumber


leaves of the plant. Mulch provides a barrier that reduces splash dispersal of the pathogen from soil to plant. In addition, mulch keeps moisture in the soil and reduces humidity in the plant canopy.

4. Stake vining plants like tomatoes, cucumbers and runner beans. This will improve air movement around the plant and facilitate drying of the leaves and fruit.

5. Do not work in plants when leaves and fruit are wet. Fungal and bacterial pathogens reproduce under wet conditions and can easily be spread on a gardeners hands or tools at this time. Wait until plants have dried completely before working in the garden.

6. Pinch off heavily infected leaves and fruit and remove them from the garden. Many leaf spot and fruit rot diseases produce new fungal spores or bacteria in every leaf spot. These pathogens are easily



M. Grabowski, UMN Extension


Photo 3: Early blight on tomato



spread through the plant to new leaves and developing fruit. Infected plant material can be buried, placed in a compost that heats up or taken to a municipal compost facility.

Remember many plants tolerate some leaf infection and still produce a good crop. Use the steps above to reduce the spread of disease and minimize it's impact on your final harvest.

Karl Foord, Extension Educator - Horticulture




Karl Foord


Photo 1: Some of the plastic tunnels that provide optimum growing conditions on the Untiedt Vegetable Farm


Karl Foord

Photo 2: Sweet corn on Untiedt Farm

Karl Foord

Photo 3: Trellised tomatoes on the Untiedt Farm

Karl Foord

Photo 4: More trellised tomatoes on the Untiedt Farm

Karl Foord

Photo 5: Trellised cucumbers on the Untiedt Farm

Karl Foord

Photo 6: Trellised canteloupe on the Untiedt Farm

Karl Foord

Photo 7: Onions on Untiedt Farm

Karl Foord

Photo 8: Honeybee hives on the Untiedt Farm

Karl Foord

Photo 9: Protective tree barriers on Untiedt Farm


If you are not already a member of a CSA (Community Supported Agriculture), I highly recommend that you consider becoming one. To be a member one pays an up front fee and receives weekly a box of currently maturing vegetables for 17 weeks of the season. This prepayment helps the farmer to achieve better cash flow for the operation and the member/shareholder gets a greater understanding how their local food is produced here in Minnesota.

To better understand where my food comes from I attended my CSA Farmer's field day. It was an enlightening experience. Not only did I see where my food comes from but also listened to Jerry Untiedt discuss how he handles various issues such as pest control and water management. I was especially impressed with the system developed for water management. All the water that runs off Jerry's plastic tunnels (Photo 1) is channeled into a natural wet area that acts in a holding capacity. When Jerry needs the water back, he pumps it back from the wet area and waters his crops.

You can see from the photos that Jerry's soil is quite sandy. With the amount of rain we have had this spring a great deal of applied fertilizer would simply have been flushed through the system and end up in our waterways. Note the sweet corn field (Photo 2) and the green plastic under the crop. This has been placed there to avoid such a loss for the farmer and then pollution for those downstream. I was very proud to know that the food I am eating is produced in a system that has been developed to avoid such problems.

Most of the vegetable acreage is under plastic providing optimal conditions for growth. This being among others: 1) lack of rain water falling on the leaves and potentially creating disease problems, 2) protection from the stong winds that buffet and damage the plants, 3) an enclosed space permitting the use of beneficial insects to control pests - in an open field they are more likely to dispurse than protect your plants, and 4) keeping the plants within an optimum growing temperature - especially critical given Minnesota's unpredictable weather patterns.

To make optimal use of space, a number of the crops are trellised such as tomatoes (Photos 3 & 4) cucumbers (Photo 5), as well as canteloupe (Photo 6). Other crops that cannot be trellised also do extremely well in the tunnels (Photo 7).

Jerry has honeybees (photo 8) and bumble bees on site to provide pollination services.

Jerry has realized that the winds in Minnesota can play havoc with plastic houses. To provide protection he has surrounded the farm with fast growing trees that slow the wind down (Photo 9). In my opinion, Jerry has been extremely innovative and environmentally sensitive as he goes about producing superior produce.

Adopt a farmer and get a first hand experience of where your food comes from.

Apple Maggots Foiled Again!

Karl Foord, Extension Educator - Horticulture

Karl Foord

Photo 1: Apples showing maggot damage next to protected apple

Karl Foord

Photo 2: Larger apple maggot trapped in nylon guard after exiting apple

Karl Foord

Photo 3: Apple maggot enters apple through flower end and leaves frass

Karl Foord

Photo 4: Small apple cut to reveal resident maggot

Karl Foord

Photo 5: enlarged view of apple maggot resident in small apple


The nylon apple maggot barriers are doing a pretty good job in protecting the apples from the attack by maggots (Photo 1). One fly did manage to oviposit her egg through the nylon mesh. The apple was ruined but at least the maggot was trapped in the barrier sock (Photo 2). Many of the unprotected apples were attacked at the flower end of the fruit (Photo 3). One of these fruits has been cut open to reveal the small apple maggot seen in the lower right half of the right hand slice (Photo 4). Photo 5 is a close up of the same slice. It is obviously critical to get these barriers in place prior to the arrival of the maggots.

The best system would have been to remove all the unprotected apples and give the maggots no chance to feed on any apples. Alas time did not permit. However, it would be best to remove the small damaged apples and get them off-site and not allow the population to build.

Pseudoscorpions are Curious, Harmless

Jeffrey Hahn, Extension Entomologist

Bunni Olson, Univ. of MN Extension

Photo 1: Pseudoscorpions look fierce but are harmless to people

A small, 1/5th inch long, reddish or brownish 'bug' with two large 'pinchers' is sometimes found in homes. Although it looks like a tick or scorpion, it is actually a pseudoscorpion. A pseudoscorpion is not an insect but is a type of arachnid, so it is related to spiders, ticks, and true scorpions. Pseudoscorpions have eight legs and pincher-like pedipalps (part of their mouthparts). They lack the stinger that true scorpions possess.

Pseudoscorpions are predators on a variety of small insects and other arthropods, like springtails, booklice, and mites. They are found in a variety of habitats, such as leaf litter, moss, and under stones and tree bark, and occasionally buildings. Despite their appearance, they are harmless to people. If you find a pseudoscorpion in your home, just physically remove it or ignore it. If possible, capture and release it outdoors. Fortunately, we rarely see more than one or two pseudoscorpions at a time. For more information, see Pseudoscorpions in homes.

Gypsy Moth Quarantine in Minnesota

Jeffrey Hahn, Extension Entomologist

(The following has been slightly modified from a June 30, 2014 news release from the Minnesota Department of Agriculture (MDA).

Bill McNee, Wisconsin Dept of Natural Resources

Photo 1: Lake and Cook counties are now under quarantine for gypsy moth

Due to the high number of gypsy moths trapped in northeast Minnesota in 2013, the Minnesota Department of Agriculture (MDA) has placed Lake and Cook counties under quarantine effective July 1, 2014.  This is the first time a quarantine for gypsy moth has been established in Minnesota.  A quarantine helps to prevent gypsy moths from being moved by human activity to uninfested counties.

Outdoor items in the quarantined counties, like logs and firewood, camping equipment and patio furniture, that could be infested with gypsy moth must be inspected and certified as gypsy moth-free before moving to a non-quarantined area. This is done in two ways:

  • Homeowners, campers and others who live in and visit the proposed quarantine will need to self-inspect outdoor household items, like RVs, camping equipment and patio furniture, before moving those items out of the quarantine.
  • A compliance agreement allows items regulated by the U.S. Department of Agriculture (USDA), including firewood, pulp wood, and saw logs, to move out of the quarantine area or to be received by a business or individual outside Lake and Cook counties. The compliance agreement outlines practices for safe handling, transportation and storage to mitigate the spread of gypsy moth. Compliance agreements are documents prepared and agreed to by the company, city, county, agency, or organization interested in moving the regulated article and the MDA, or USDA in the case of interstate movement.

The MDA has been tracking and treating gypsy moth in Minnesota for decades. Since April 2013, MDA staff has been in discussions with the timber and nursery industries, as well as local, state, federal, and tribal officials on a potential quarantine. When 2013 trapping results showed a record number of gypsy moths, 90 percent of which were located in Lake and Cook counties, an advisory group recommended a quarantine of the two northeastern most counties in the state to the Commissioner of Agriculture.

Details of the quarantine can be found at here.  For questions on gypsy moth or the quarantine, call MDA's Arrest the Pest Hotline at 888-545-6684 (voicemail) or email gypsy.moth@state.mn.us. 

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