Yard & Garden Line News Volume 4 Number 1                                                               January 1, 2002

Features this issue: Dursban No Longer Available to Homeowners Plant Disease Clinic Remind Yourself of Warmth with Indoor Palms When Ya Gotta Plant... Flavorful Fungi Editorial Notes

Dursban No Longer Available to Homeowners
Jeff Hahn, Assistant Extension Entomologist

Dursban label. Photo credit: Y & GL

December 31 was the last day retailers could sell the insecticide chlorpyrifos, commonly known as Dursban. The EPA decided to phase out Dursban after it was reviewed under the Federal Quality Protection Act (FQPA). FQPA holds a much higher standard for pesticides then has been used in the past. It was decided that its uses in agriculture and urban areas presented too much combined exposure, making the potential risks too great. Agricultural and forestry uses remain largely unchanged. Except for child resistant ant and roach baits, however, Dursban can not be bought by home owners.

Dursban has been a popular and widely used insecticide in and around homes and in the landscape. It was effective on a wide range of insect pests, could be used on many different plants and other sites, had a reasonably long residual, and was easy to find in many stores. One container of Dursban was often all that was needed to take care of most pests in and around homes. So what do people do now?

First, keep in mind that because you see an insect, doesn't automatically mean you need to treat it with an insecticide. Integrated pest management (IPM) stresses monitoring for pests, and then first using a combination of nonchemical methods while using pesticides as a last resort. There are many methods, depending on the specific pest, to reduce or eliminate insects without resorting to chemicals.

If you do find that an insecticide is appropriate what can you use? Although you can no long buy Dursban, you can still use any remaining product you own. It is not a banned insecticide. There is no time limit for residents to use any remaining Dursban they own. Be sure to use any remaining stock according to label directions.

If you don't have any Dursban on hand what are the options? Although there isn't any one insecticide that can be used as widely as Dursban had been, there are effective alternatives already available for nearly every pest situation where Dursban may have been used (see Yard and Garden News, February 1, 2001) http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-Feb0101.html#bell.

Unfortunately, it may be not always be as simple as just going to your favorite retail store to pick up an insecticide to replace Dursban. Although a particular product may be generally available, the retail store in your area may not carry it.

Another challenge will be identifying the product you want to buy. When you bought chlorpyrifos, you just looked for a product that said Dursban on the container. Newer products generally don't do that. A product name very often does not tell you what type of insecticide it is. For example, Bug-B-Gon Multi-Insect Liquid gives you no clue as to what the active ingredient is.

To find out what chemical is in the container, you need to look carefully at the label for the active ingredient. It is usually found in very small print. Once you learn what a product name contains, you still need to look carefully at the ingredients. Some products lines have very similar sounding trade names with different active ingredients. In others cases two products may have the same trade name and still have different active ingredients. There is a lot of potential for confusion. You also need to check the label to ensure that you can apply the insecticide on the plant or the site you wish. This part of the label may or may not be broad. The moral of the story is look very carefully at labels before buying products.

We will survive without Dursban. In fact we will also survive when diazinon is phased out in 2003. It may be more challenging at times to deal with insect pests but by using IPM and newer insecticides, life will go on as usual.

Get the low down on this month's insect pests at Insects http://www.extension.umn.edu/projects/yardandgarden/EntWeb/Ent.htm
Plant Disease Clinic
Beth Jarvis, Yard & Garden Line

Plant diseases, while at least irksome to a gardener, may mean economic loss to a commercial grower. When that greenhouse, tree nursery, golf course or farmer needs to know what's infecting their crops, one place they turn is the Plant Disease Clinic.

The Plant Disease Clinic, housed on the St. Paul campus, has been providing the needed laboratory services for over 16 years. Services include traditional methods such as culturing and microscopic examination as well as ELISA tests for viruses and some bacteria. (ELISA is short for enzyme-linked, immunosorbent assay).

Sandee Gould, the clinic's only full time employee, has seen the frequency of plant diseases change some during the 10 years she's worked there. New diseases such as daylily rust show up and old diseases such as Sclerotium rolfsii on perennials keep changing. Sclerotium had been seen some in greenhouse production but not in someone's garden where it had overwintered–until this summer. The extensive shipping of plant material and the changing climatic conditions play a role in the increasing variety of diseases seen in the clinic.

(Articles on these diseases can be found at:
http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-Aug0101.html#mold
http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-Aug1501.html#hems )

Plant diseases are caused by fungi, bacteria, viruses, or mycoplasms/micellular organism. About 80% of plant diseases seen in the clinic are cause by fungi.

To test for fungi, symptomatic sections of the plant are cleansed of surface contamination and small pieces are placed on Petri dishes, or "plates". The Petri dishes have a small amount of sterile agar, a gelatin-like substance, in each. Each type of agar will encourage the growth of some fungi and limit others. In the Clinic, the commonly used agars are acid potato dextrose agar and water agar.

The fungal growth is examined under a microscope. Identification of the fungal spores and structures that form on the agar is the basic way specific fungi are identified. Once the disease organism is identified the control recommendations can be made.

A yellow and pink flowered fiberous rooted begonia bloomed gaily at the end of a lab bench (table). Sandee shrugged and said it had come in with Impatiens necrotic spot virus. It had grown out of the worst symptoms and was doing quite well. She said since it was pretty she'd decided to keep it around. When it's done blooming, it will hit the trash.

Viruses are some of Sandee's favorite diseases because there are a lot of them and they can be, as she says with a laugh, "sneaky" in how they express themselves in their host plant. For example, impatiens necrotic spot virus can look like a fungal leaf spot to even the semi-trained eye. Viruses can cause stunted plants, distortion as well as mosaic patterns in the leaves of some plants, to name a few symptoms.

Sandee also considers Phytophthora "an interesting critter". Phytopthora species are major pathogens of potatoes, tomatoes, soybeans, and many other crops including shrubs. It's the fungal storage rot that caused the Irish potato famine.

Verticillium, a fungus that infiltrates plants' vascular systems causing them to wilt, is also a disease that piques Sandee's interest. It's common in potatoes, tomatoes, peppers, and many herbaceous plants and trees. It's always a challenge to isolate this organism.

The Plant Disease Clinic is largely self-supporting which means taking on extra projects during the slow winter months. Some fungicide trials have been conducted on bulbs and floral crops and growing media was evaluated for the presence of disease suppressive fungi.

Thre are several other tests and greenhouse assays performed during winter months. Testing grain and animal for storage molds for farmers and the Veterinary Diagnostic lab starts after harvest. As we talked, several 2000 mL flasks of autoclaved media sat in hood, cooling, before being poured into Petri dishes and used for mold identification.

Field soil testing for Aphanomyces sp. and Rhizomania, pathogens of sugar beets, are also done during the winter. Both tests are 6-10 week bioassays conducted under greenhouse conditions. Another test conducted during the winter is barley loose smut assays for MN Crop Development.

The Plant Disease Clinic brochure is at: http://www.extension.umn.edu/distribution/cropsystems/DC3170.html

Remind Yourself of Warmth with Indoor Palms
Deborah Brown, Extension Horticulturist

Palms in Florida. Photo credit: Deb Brown

After an unusually mild autumn, cold winter has finally set in, and many of us are getting the urge to surround ourselves once more with green and growing plants – preferably viewed up close in a warm, tropical setting.

While potted palms can't substitute for a week in Hawaii, they can lend a touch of the tropics to almost any interior landscape. A fresh green leafy palm might be just the thing to fill the void left when you banished the Christmas tree from your living room. And a healthy, full specimen can be very beautiful in its own right..... as long as it's well-maintained.

Not all palms are created equal, however. Some will only thrive in a brightly lit sunny location, while others tolerate the lower light levels that are more typical of most Minnesota homes, especially in winter. Since a well-grown palm is not inexpensive, regardless of size, it pays to choose carefully, keeping its ultimate destination in mind.

If you're thinking of a dimly lit corner, forget it! Even the so-called "shade-tolerant" palms need fairly bright indirect light most of the day. Without adequate light your plant will lose all its lower fronds and look like a stick -- or series of sticks -- with a few leaves on top. A plant that pathetic adds nothing to a room, unless, perhaps, you think of it as a conversation piece.

Here are some of the more attractive palms you're likely to discover at florists' shops and garden centers. You may find others, as well. Just make sure you know their environmental requirements before you buy.

* Parlor Palm or Neanthe Bella, Chamaedorea elegans: This slow-growing, dwarf palm has more shade tolerance than any other, so it's one of the best choices for relatively low light. A shrubby plant with many stems or "canes", you'll find it available in sizes ranging from only eight or ten inches -- perfect for a desk or coffee table -- to several feet. It maxes out around four to six feet.

Palms in Minnesota. Photo credit: U of MN Extension Service

Two close relatives, Reed Palm, Chamaedorea Seifrizii, and Bamboo Palm, Chamaedorea erumpens, share the ability to survive in relatively low light, but may grow several feet taller, especially in a brighter location. All three of these palms -- parlor, reed and bamboo -- do best in reasonably warm temperatures. Keep them away from leaky windows and cold entryways where they'd be exposed to blasts of frigid air.

* Kentia or Sentry Palm, Howea Forsterana, is a tall, stately slender plant with gracefully arching large fronds. Kentia palms can withstand lower light levels better than most large plants, according to Richard Gaines, author of Interior Plantscaping. These palms do best in "medium" rather than "low" light, but are less sensitive to cool temperatures than the Chamaedorea species.

Though slow-growing, a Kentia palm is capable of eventually reaching your ceiling, at which time you'd have to give it away.... or move to a more spacious home. You can't prune palms back!

* Lady Palm, Rapis excelsa, lends a distinctively "oriental" look to interior landscapes. Like the Kentia palm, it's slow-growing and suitable for medium light locations. And like the Kentia, you'll find it priced on the high end of the scale, due, no doubt, to the long time it takes to grow to marketable size.

Lady palms are shaped like shrubs rather than trees, with many thin stems growing from the soil. Their unusual dark green foliage consists of several leaflets on each frond, joined so as to remind you of fingers on a hand. (A lady's hand, no doubt.)

* Chinese Fan Palm, Livistona chinensis, and European Fan Palm, Chamaerops humilis, are prized for their unusual fan-shaped foliage. Fewer people are able to grow them indoors successfully though, because these two palms demand higher light levels. But if you do have a bright, sunny south or west-facing set of windows, either one of these palms could be an exotic addition to your decor.

Both fan palms are grown as single stem trees or multi-stem shrubs; you're more likely to find the shrub-form. Chinese fan palm has huge leaves that appear fringed at the tips, while European fan palm leaves are stiffer, more deeply cut and lacy looking.

Daily Care:

Fertilizer burn on leaves. Photo credit: Deb Brown

Though their light requirements may differ, all these palms have similar needs when it comes to water and fertilizer. In fact, dried brown leaf tips or leaf margins, two of the most common problems facing indoor palms, are related – directly or indirectly – to how they are watered and fertilized.

Keep palms relatively moist. In spring and summer, or when temperatures are warm and days are longer, water them as soon as their soil feels dry a little below the surface. Allow the soil to get slightly drier in winter.

It's important that potting soil drains well and containers you use have functioning drain holes. Water palms thoroughly, then spill or siphon off excess water that collects in the tray or saucer below the pot.

Fertilize lightly from late winter through early autumn, the time when houseplants are likely to grow most actively. A build-up of fertilizer salts in the soil results in those dreaded brown tips and edges, especially if you allow the soil to get too dry between waterings. If you're unsure about fertilizing, err on the side of too little rather than too much. You can always fertilize again, if necessary.

Finally, keep palm fronds clean. Spider mites are attracted to dusty foliage and can balloon into a serious problem, particularly in winter when relative humidity is low indoors.

When Ya Gotta Plant...
Beth Jarvis, Yard & Garden Line

Lisianthus can be planted now. Photo credit: Beth Jarvis

Most years, January is the coldest and seemingly longest month of winter with spring a small eternity away. Garden centers tempt us with sales well before the ground is workable. And, that's when many seemingly sane gardeners lose it. They emerge from their favorite seed purveyor laden with planting goodies.

Now is not the time to plant tomatoes. The majority of garden seeds need to be started 6 to 8 weeks or 4 to 6 weeks before being transplanted outside. Starting such seeds months earlier, under the relatively low light levels in home seed starting setups, will yield leggy, overgrown, root-bound transplants. They will suffer more transplant shock than smaller transplants, so you're not gaining anything. Cheer up! If you have seeds of lisianthus, start them now. Greenhouse growers allow 20 to 22 weeks to raise them to a size marketable in a 4" pot. The Jung catalog lists them as blooming 21 weeks from when seeds are planted. Seedlings emerge in a couple of weeks, but they just grow slowly. (But they're so worth it.)

Below is a list of other flowers and a vegetable or two you'll be able to plant soon, so you can shop for the seeds now. These are pretty common things that need nothing more than time to grow. No special seed treatments. If you live in the Twin Cites, you can generally expect our last average frost to be mid-May; if you're in northern Minnesota, USDA zone 3, plan for planting out around the end of May. Add a week to the weeks listed below to allow time to harden off the plants before planting outside.

Catharanthus roseus. Photo credit: All-American Selections

20+ weeks
Lisianthus (Eustoma grandiflorum)

12-16 weeks (plant after mid-Jan. in TC)
Geraniums (Pelargonium x hortorum)
Tuberous rooted begonias(Begonia x tuberhybrida)

12 weeks: (plant mid-Feb.)
Mealycup sage (Salvia farinacea)
Periwinkle (Catharanthus roseus)
Wax begonias (Begonia sempervirens)
Impatiens (Impatiens walleriana)
Onions--see:
http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-Feb0100.html#onion http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-Feb0101.html

10 to 12 weeks: (plant mid to late Feb.)
Celery
Cupflower (Nierembergia hippomanica )
Edging lobelia (Lobelia erinus)
Heliotrope (Heliotropium sp.)
Ice plant (Mesembryanthemum chrysallinum)
Livingstone daisy (Mesembryanthemum criniflorum)
Monkeyflower (Mimulus x hybridus, M. cupreus)
Petunias (Petunia x hybrida)
Wishbone flower (Torenia fournieri)

References:
Reilly, Ann. Success With Seeds. (out of print)
Ball, Vic (ed.) The Ball Red Book, 15th Edition.

For more seed starting info:
Y & Garden Brief: "Starting Seeds Indoors"
http://www.extension.umn.edu/projects/yardandgarden/ygbriefs/H236startseeds.html

Flavorful Fungi
Janna Beckerman, Extension Plant Pathologist

Different sizes and ages of mushrooms ensure several harvests from a single box! Photo credit: Janna Beckerman

This is the time of year when many Minnesota gardeners begin to wish they could garden. The need is palpable, and expresses itself in many peculiar ways. Some folks go on houseplant purchasing binges. Others prefer the seed purchase binge. The lucky among us hop on a jet and tour southern gardens. However, a few weeks later, we realize that it is still winter outside, as we sit surrounded by seeds packets, saggy houseplants or tacky tourist souvenirs. And, we still can't garden. Or can we?

When most people think gardening, they think of cute little green seedlings, or flowers or tomatoes. But there is another type of produce uniquely suited for winter gardening, especially in Minnesota: Mushroom gardening.

Mushroom growing is a truly rewarding hobby that many people never attempt. In addition to the misconception that most fungi are poisonous, many people think it is "too hard" (wrong!) or "too weird"(no comment). Weirdness aside, today kits have been developed to easily grow edible mushrooms at home. Mushrooms can be successfully grown in the basement, bathroom or closet. And the variety of mushrooms you can grow has never been better, from the everyday grocery store mushroom (Agaricus bisporus), to Asian favorites like Shitake (Lentinus edodes) or European gourmet mushrooms such the pom-pom or bears head (Hericium uva-ursi).

If mushroom growing is so easy, then why don't more people do it? One of the biggest mental blocks preventing people from mushroom gardening is the fact that mushrooms grow from microscopic spores, not seeds. You can't just buy a packet of "spores" and dump them in the ground and expect mushrooms to come up! Spores must be collected in a relatively sterile environment. These spores are then used to inoculate grains, seeds or dowels to produce "spawn," the vegetatively growing fungal tissue scientists call mycelia (The mycelia are indicated by the yellow arrow in Fig. 1). Spawn is the seed to a mushroom grower!

The spawn is then used to inoculate a specific type of substrate, depending on the type of mushroom you are growing. Like plants, different mushrooms require different growing conditions. However, unlike most plants, mushrooms have no chlorophyll, and are required to get all their nutrients from whatever organic matter is in their growing medium. This makes what you are growing them in extremely important! Depending on the type of mushroom you are growing, the substrate or compost is composed of various materials such as corncobs, cottonseed, sawdust, straw, logs, gypsum and nitrogen supplements. The substrate is sterilized and then the spawn is worked into the compost, or the spawn-covered dowel is inoculated into the logs.

Over time, the mycelia grow throughout the substrate. Getting the mycelia to fruit requires as little as watering (for the white button mushroom) to submerging the "log" or "block" (either a real log or a bag inoculated with shiitake or other type of fungus) in cold water for 24 to 48 hours. Fruiting can take from 2 weeks to 2 months. Size is no indication of maturity in mushrooms. Ripe mushrooms vary from small buttons to large caps. Crops are harvested over a period of several weeks to even several months.

Mushroom gardening is so simple that it can be summarized into three easy steps:

1) Acquiring spawn
2) Inoculating (introducing) the spawn to the compost or substrate it is to grow on. This could be a box of compost, a bag of sterilized sawdust, or even a log!
3) Getting the fungus to produce mushrooms.

They are two main ways you can go about mushroom growing: kits, which have everything ready for you, just add water (kits allow you to start at step two or three); or buying the starter culture (referred to as 'spawn') and getting the mushroom growing substrate yourself or purchasing it separately. As you can imagine, kits are the more expensive route to go, but is recommended for the novice, the fearful or the forgetful people who can't remember to water things on a regular basis(you know who you are)! For first time mushroom growers, kits are the way to go!

One of the easiest mushrooms for beginners is the common grocery store mushroom, Agaricus bisporus. Kits consist of a box with spawn, casing (usually sphagnum moss which is placed on top to keep the compost moist) and compost. After the casing is moistened, the only care required is a daily misting to keep the casing moist. After the mycelia has covered much of the compost, the box can be briefly chilled or just plain left alone to initiate the development of the mushrooms, which will form in 1-3 weeks. Not convinced how easy this is? More detailed instructions can be found at: http://www.mushroomadventures.com/instructions.html

For the more gastronomically daring, here are a few other varieties of mushrooms to consider:

Tenting keeps the plastic from sticking to the log. Drawing: Janna Beckerman:

Oyster mushroom (Pleurotus spp.):
Kits often consist of a bag containing a mycelial-covered block. The bag is watered thoroughly and then tented, which consists of placing skewers or dowels in such a way to prevent the bag from touching the block. Remember, fungi are alive and need to "breathe." A fluorescent light or daylight (but not direct sunlight) will encourage fruiting. Small bumps, or what mushroom farmers call "pins"(indicated by the red arrow in Fig. 1) should start to push through the casing layer in 1-2 weeks. As mushrooms start to form, continue misting lightly. Over misting will cause them to rot. Continue with this misting procedure until the mushrooms are ready to pick. After the first crop, begin misting process again. The mycelium will digest more compost as it readies itself for the next "flush" of mushrooms. This mushroom (some species actually do have a taste reminiscent of oysters) is delicious either fried or grilled.

Shitake mushroom (Lentinus edodes):

Shitake are commonly used in Asian cuisine Photo credit: Deb Brown

Like the oyster mushroom, kits are usually sent as a mycelial-covered block in a sterile bag. The block remains in the bag and is "tented," covered to keep dust and other spores from landing on it, but allowing airflow necessary for fruiting to occur by inserting dowels to prevent the bag from sticking to the block. Some kits only require that you slash open the bags. At this point, the blocks need to be misted several times a day to prevent the mycelia from drying out. The mushrooms emerge from the cut holes and grow until harvesting. Usually, 2-3 additional harvests can be "coaxed" out of the block before it is ready for your own compost pile. This mushroom is used in hearty soups (think beef-barley) and stir-fries.

For more information on where to purchase kits, mushroom hunting, identification and culture, go to: http://www.fungifest.com or http://www.mushroompeople.com

Happy Growing!
Test your diagnostic savvy monthly with Disease Watch at: http://www.extension.umn.edu/projects/yardandgarden/PlantPathWeb/Plpa.htm
Editorial Notes

Wax begonias Photo credit: Beth Jarvis

What a difference a month makes! Thirty days ago we had above normal temps and bare ground and now it's a normal, "brisk" winter complete with snow. But, beats the daylights out of Buffalo, NY with something like 7 feet of snow between Christmas and New Year's!

Next issue we hope to share the results of a third year of apple bagging for insect and disease control. Also in upcoming issues: all about the U's newest strawberry releases, info on raising pears in the north, results of the U's annual flower trials, Lyme disease ressearch and perhaps some info on some of the animals that share our environment.

Please feel free to cut and paste any of the articles for use in your own newsletters. All we ask is that you give our authors credit.

Back issues Yard & Garden Line News are on the Yard & Garden Line home page at www.extension.umn.edu/yardandgarden/. Our home page has clickable links to most of the components of the Yard & Garden Line, such as Bell Museum of Natural History, INFO U and the Soil Testing Lab.

Deb Brown answers gardening questions on Minnesota Public Radio's (MPR) "Midmorning" program on the first Thursday of every month at 10 a.m. Katherine Lanpher hosts the program that is broadcast on KNOW 91.1 FM, and available state-wide on the MPR news radio stations.

If you have gardening questions, please call the Yard & Garden Line at (612) 624-4771.

If you would like to receive an e-mail reminder when the next issue of the Yard & Garden Line News is posted to the web, just send an e-mail to: listserv@lists.umn.edu (note: the second E in listserve is omitted), leave the subject line blank, then in the body of the message, type: sub yglnewslist or to unsubscribe, enter: unsub yglnewslist

Happy gardening!

Beth Jarvis
Yard & Garden Line Project Coordinator


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