October 2017-November 2017
In This Issue
Garden NibblesLunch - N - Learn Series
Garden Nibbles Lunch-N-Learn's are being held in all 5 counties each month in 2017. KariHoule will be leading each of these 30 minute sessions. Sessions run from 12:15 pm to12:45 pm and are FREE, you are welcome to bring your own lunch. The topics for Octoberand November respectively are "Composting Basics" and "Green Up with Groundcovers".Log on to http://web.extension.illinois.edu/abhps/ for to register online. If you are unableto register online, please call your local extension office listed below to register.
October 16 & November 13 - Hancock County Extension Office - 217-357-2150
October 17 & November 14 - Pike County Extension Office - 217-285-5543
October 11 & November 15 - Schuyler County Extension Office - 217-322-3381
October 26 & November 16 - Adams County Extension Office - 217-223-8380
October 20 & November 17 - Brown County extension Office - 217-322-3381
Downy Mildew of CucurbitsDowny Mildew of Cucurbits
By Mohammad Babadoost
Downy mildew, caused by Pseudoperonospora cubensis, is one of the most important foliar diseases of cucurbits. It has been reported worldwide in production areas where humidity and temperature favor its establishment. Downy mildew occurs in temperate and tropical areas with sufficient leaf wetness periods.
Without adequate control measures, downy mildew can result in major crops losses in cucurbits in both open fields and greenhouses. In Illinois, this disease usually occurs toward the end of the growing season, as the pathogen is blown from the Southern states northward.
Downy mildew only affects leaves. Symptoms of downy mildew vary with the host and the environmental conditions. The first symptom is usually the appearance of pale green areas on the upper leaf surface (Figures 1). The pale green areas soon become yellow in color and angular to irregular in shape, bounded by the leaf veins. As the disease progress, the lesions may remain yellow (Figure 1) or become brown and necrotic. During moist weather the corresponding lower leaf surface is covered with a downy, pale gray to purple mildew (Figure 2).
Symptoms on cucumber and squash are angular lesions that are limited by the leaf veins (Figure 1). On watermelon and cantaloupe, symptoms are typically irregular-shaped lesions on the foliage that turn brown rapidly. Infected leaves may experience an upward leaf curl. Symptoms on watermelon and cantaloupe are not as distinctive as on cucumber and squash and could be mistaken for other diseases such as anthracnose. Severe infection results in leaves that are completely dead and curled up. This symptom has been described as "wildfire" as the leaves appear to be burned.
Pseudoperonospora cubensis is an obligate parasite, meaning that it requires live host tissue in order to survive and reproduce. Because of this feature, the pathogen must overwinter in an area that doesn't experience a hard frost (e.g., southern Florida) and wild or cultivated cucurbits are present. The pathogen produces large (20 - 40 x 14 - 25 mm in diameter), lemon-shaped sporangia (spores). The sporangia are borne singly on the pointed tips of sporangiophores that branch at acute angles. Primary infections in the field or garden generally come from spores produced on southern grown crops and carried progressively northward on moist air currents during the spring and summer. The sporangia are disseminated locally from plant to plant and from field to field by splashing rains, moist air currents, insects, tools, farm equipment, the clothing of workers, and through the handling of infected plants. Heavy dews, fogs, frequent rains, and high humidity favor infection and rapid multiplication of the pathogen. Symptoms appear 4-12 days after infection.
The pathogen favors cool and moist. Optimum conditions for sporulation are 59EF with 6-12 hours of moisture present (usually in the form of morning dew). Once infection occurs a new crop of sporangia are produced in 4 to 12 days, depending on temperature and day length. The downy mildew pathogen does not overwinter in plant debris in Illinois. The pathogen may overwinter in some areas as thick-walled oospores which are capable of withstanding extremes in temperature and dryness. It is not clear if these oospores play any role in disease development. Five pathotypes have been described for P. cubensis. All described pathotypes infect susceptible cucumber and netted melon cultivars, but not all are compatible of infecting watermelon, squash, or pumpkin. This explains why cucumber and netted melons are sometimes heavily infected, while - 3 - nearby watermelon, squash, or pumpkin are not affected.
Control of downy mildew on cucurbits is achieved by planting resistant cultivars, early planting of crops, and/or fungicide sprays. Cucumber cultivars resistant to downy mildew are available. Early plantings for crops for July harvest often escape infection with downy mildew pathogen, while plantings for harvest in August or later in the season are vulnerable. Because of the potential for rapid plant infection, sprays should be initiated on a preventive basis for vulnerable plantings. Fields should be scouted regularly for disease development. When downy mildew is present, fungicides with systemic activity tend to be more effective than protectants. Using systemic fungicides with protectants will minimize resistant development in the pathogen. A disease-forecasting program is available (www.ces.ncsu.edu/depts/pp/cucurbit). For the update information on controlling cucurbit downy mildew, especially fungicide applications, refer to the Midwest Vegetable Production Guide for Commercial Growers, publication C1373 (http://www.btny.purdue.edu/pubs/id/id-56/).
White GrubsWhite Grubs
By Dr. Phil Nixon
Originally published in Home, Yard, and Garden Newsletter on 8-15-17
Japanese beetles and masked chafer adults are attracted to moist soils and, apparently, to green grass to lay their eggs. In years when rainfall is abundant, nonirrigated (as well as irrigated) turf stays green and attractive to egg-laying female beetles. As a result, eggs are laid over all of these areas, resulting in fewer eggs laid per square foot. The resulting larvae are usually fewer than the 10 to 12 white grubs typically necessary to cause turf injury. In those areas of Illinois with an abundance of rainfall this year, such as in the northwestern part of the state, grub treatment may not be needed.
In dry years, the beetles are strongly attracted to the moist soils and green grass of irrigated turf to lay their eggs, laying relatively few eggs in the dry, brown, unwatered turf areas. This results in high numbers of white grubs in watered turf, which cause damage in the form of wilted, brown turf that is easily pulled back due to the white grubs eating the roots.
In much of Illinois, irregular rains have caused many areas of turf that are not irrigated to green up for a few days and then turn brown for a week or so until the next rain. These rains do not appear to be wetting the soil very deeply. As a result, the Japanese beetle and masked chafer adult beetles have likely laid considerably more eggs in irrigated turf. This sets up a situation in which damage is likely to become apparent in the second half of August and later, when the resulting white grubs grow large enough to cause serious turf damage.
After the first week of August, most of the white grubs should have hatched, allowing scouting to determine for certain whether treatment is necessary. Scout for white grubs by cutting through the turf with a heavy knife. Pull the sod back to reveal the white grubs in the root zone. Check the soil hanging to the turf roots for white grubs, as well as the soil below the roots. Till the upper 2 to 3 inches of soil with your knife to check for white grubs in that region as well. If the soil is dry, till a couple of inches deeper to check for grubs that may have migrated down to moister soil.
If at least 10 to 12 grubs per foot square are present, turf damage will be likely to occur without treatment. Apply an insecticide such as chlorantroniliprole (Acelepryn), cyantraniliprole (Ference), trichlorfon (Dylox) or one of the neonicotinoids imidacloprid (Merit), clothianidin (Arena), or thiamethoxam (Meridian). Do not apply Ference or neonicotinoids to turf with blooming weeds or flowers to avoid killing pollinators.
Hover Flies: Garden WarriorsHover Flies: Garden Warriors
By Kelly Allsup
Hover flies (aka syrphid flies or flower flies) are likely buzzing about any nectar-producing flower in your garden this summer. These flies, commonly mistaken for bees, are one of the most prolific pollinators in the Illinois garden, according to University of Illinois Extension horticulture educator Kelly Allsup. In addition to their pollinator services, their larvae are voracious meat eaters.
Hover flies are excellent fliers, flying backwards and forwards and hovering over their beloved flowers. Hover flies are yellow and black bee-mimics that feed on pollen, nectar, and honeydew (frass of phloem feeders like aphids). They mimic bees and or wasps for protection against predators such as birds. Allsup says they can be easily distinguished from bees because they are shiny and bees are fuzzy. They can be distinguished from wasps in that they have two wings and wasps have four. Sandy Mason, state Master Gardener coordinator, simplifies it with the saying, "Count the wings. Two wings: fun; four wings: run!"
With many generations per growing season, hover flies are here to stay. The female hover fly will usually lay her eggs on or near aphid colonies and in two to three days the larvae will hatch. "The larva, which is technically a maggot, is muted green, legless, worm-like, and can be found on the undersides of leaves eating aphids, thrips, scale, caterpillars, and mealy bugs," Allsup says. "These larvae are great garden warriors and can be put in the same category as ladybugs and lacewing larvae in terms of the effectiveness in demolishing an aphid population. The larvae grasp the prey with their jaws, hold them up in the air, suck out their body contents and toss the exoskeleton aside."
According to Cornell University, the larvae can eat up to 400 aphids. The larvae feed for about seven to ten days before they pupate, which takes about 10 days. "Therefore, if you see an aphid or mealy bug infestation in your garden, be sure to turn over the leaves to look for these beneficial maggots before you spray," Allsup says.
The University of Minnesota just released a trial garden report on flowers that attracted pollinators and listed several annuals as excellent additions to lure hover flies to your garden. Zinnias were number one in attracting these fly pollinators, followed by 'Tangerine Dream' and 'Bambino' marigolds. The list also included Salvia 'Coral Nymph,' Rudbeckia 'Irish Eyes,' sunflower 'Lemon Queen,' and snapdragons as top attractors.
Going Organic: Are Organix Pesticides Safer than their Synthetic CounterpartsGoing Organic: Are Organic Pesticides Safer than their Synthetic Counterparts
By Chris Enroth
Homeowners use a lot of pesticides. Statistics show that homeowners use three times more pesticides per acre than commercial agriculture producers. The United States Fish and Wildlife Service estimates the number to be even higher; their reports claim pesticide use in lawns is 10 times higher than in commercial agriculture.
Though not quite ready to ditch the bug and weed killers, homeowners are seeking alternatives to conventional pesticides. Many homeowners are turning to organic pesticides due to the growing perception that these pesticides are safer. But are organic pesticides safer than their conventional cousins?
That is a good question, says University of Illinois Extension horticulture educator Chris Enroth. First we should define what makes a pesticide organic. In most circumstances, an organic product, whether it is a pesticide or a fertilizer, is derived from the remains or byproducts of a living or once-living organism. Typically these products are marketed as natural, which reinforces the image these products are from nature and are therefore harmless.
Enroth cautions, Just because something is labeled organic or natural does not mean it is safer to the homeowner or unable to cause harm to the environment. Botanically derived pesticides are not always safer; in fact, some can be more dangerous.
Before being sold, all pesticides undergo studies to define their acute toxicity. In other words, these studies look to determine what immediate dangers specific pesticides pose. Scientists rank the acute toxicity of a product based on the lethal dose that kills 50 percent of the test sample, termed the LD50. Because a low LD50 means it takes a smaller amount of a product to cause harm, a lower LD50 translates to a higher toxicity in a product. Several botanically derived pesticides have a low LD50, meaning they are quite toxic to humans. Examples include nicotine, rotenone, and some pyrethrins.
Fortunately, several of these products have been taken off the market, says Enroth. However, many home recipes incorporating these dangerous active ingredients still exist online.
The important thing to keep in mind is that, like synthetic pesticides, organic products vary and have a broad range of toxicity levels, says Enroth. Some organic pesticides can be very harmful to humans, while many others are perfectly safe.
All pesticides, synthetic or organic, must be stored in a locked cabinet out of reach from children. When applying any pesticide, always read the product label and research the toxicity and environmental hazards. Take proper precautions to protect yourself, your neighbors, and the environment.
Although pesticides are an important tool in our tool belt, they should always be our last resort, says Enroth. In my yard, pest prevention starts with good plant culture. Correctly maintaining your plants will give them a competitive edge on weeds, insects, and disease.
When a pest becomes overwhelming, first research the offending organism and then take appropriate action. Start with the least offending measures, such as picking off troublesome insects or removing diseased foliage. Sharp streams of water can knock down many pest insects such as aphids.
Horticultural soaps and oils are useful for slower-moving insects and protecting from certain diseases when applied at the appropriate time. When these efforts fail to control a pest, a pesticide may be the final option, says Enroth. Whether you choose a synthetic pesticide or an organic pesticide, be conservative in what chemicals you add to the landscape.
Or maybe just accept the pest and cut out the pesticides altogether, Enroth says. After all, the blooming creeping Charlie and dandelions are a sight to behold in my lawn.
Gardening With Your SensesGardening With Your Senses
By Kelly Allsup
Gardeners may be familiar with the sense of calm and peace that can come from relaxing in a patch of fragrant and colorful flowers. It's little wonder that the gardens have been harnessed for their therapeutic effects.
"Horticultural therapy is about people, not the plants," says University of Wisconsin Extension Master Gardener Program director, Mike Maddox. Maddox has spent the latter part of his career teaching people how to connect to each other using gardens as their medium. He explains, "Plants have always been the cornerstone of our existence, they are in our DNA."
In reality, we do share a quarter of our genes with the rice plant and we can learn about ourselves from studying their DNA. But more importantly, in horticultural therapy lingo, we have a natural connection to plants and want to learn more about them.
University of Illinois Extension horticulture educator Kelly Allsup developed a sensory garden program to promote the horticultural therapy concept and connect gardeners to nature. She demonstrates how much one uses their senses in the following imagination exercise.
"Imagine you are sitting in a garden. Any garden you can imagine. It can be a garden you have been in before, the garden of your dreams, or a pretend garden with purple trees.
"Look at the sky. What color is it? Look at the flowers. What kind are they? Oh look… Your favorite fruit is ready for picking. Is it an apple? Strawberry? Is it sweet?
"Now find a bench, sit, and rest. Do you feel the sun on your face? The breeze in your hair? You reach down to touch the leaves. Are they soft, fuzzy, smooth, or rough?
"What flowers do you smell? Do you smell the grass? Herbs? Soil? Water from the creek or fountain?
"What do you hear? A waterfall? Birds bursting into song? Bees buzzing, or squirrels scurrying? How do these sounds make you feel?
"You suddenly hear someone walking towards you. It can be anybody. Someone you have loved and lost. Someone you see every day. Someone who lives far away. Someone famous. Someone funny. Someone kind."They sit next to you on the bench to hold your hand."
Was this imagination exercise fun, emotional, exciting, or intriguing? Thinking about the senses we use in a garden setting has caused some gardeners to reevaluate what they are planting. Gardeners are using plants to deepen their sensory experience of nature and some are using the sight, taste, feel, smell, and sound of the garden to repair their soul.
Therapy through nature and horticulture has been trending, as we become a more holistic society trying to reconnect to the natural world. Sensory plants may benefit gardeners with impaired sensory functions, children who have difficulty expressing themselves, people with disabilities, or some who just want a positive experience not created on a screen. "A gardener recently told me he didn't care what the plant looked like anymore, but wanted to smell his garden," Allsup recalls.
As you continue your gardening endeavors this season, think about some of the following plants that may enliven the senses. For taste, plant flowers like stevia, daylilies, hibiscus, sunflowers, nasturtiums, and borage. Or plant vegetables like lettuce, swiss chard, peas, spinach, arugula, beet greens, chives, and herbs. Be sure the garden has not been sprayed with pesticides before nibbling.
For feel, plant annuals like sensitive plant, succulents, licorice plants, silver falls, dusty miller, and chenille plant. Or choose perennials like silver mound, lambs ear, fountain grass, and Irish moss.
For smell, pick herbs like rosemary, lemon verbena, lavender, chocolate mint, scented geraniums, and patchouli plant. Annuals like heliotrope, flowering tobacco, four-o-clocks, sweet alyssum, popcorn plants, and ageratum are good choices. Or plant perennials like viburnum, abelia, lilac, Plumeria, witch hazel, catmint, sweet shrub, and creeping phlox.
For sound, add grasses, wind chimes, water features, or a bird bath.
What senses are awakened when you walk through your garden? For more information on therapeutic horticulture provided by Mike Maddox please visit http://fyi.uwex.edu/therapeutichorticulture/.
Fall Garden Mums in the GardenFall Garden Mums in the Garden
By Kari Houle
Everywhere I go I see huge displays of fall garden mums for sale. Beautiful colors and a reminder of cooler days to come. Mums are a great addition to containers and the landscape to add color when our summer flowers are faded or finished. With a little extra planning those mums you buy now can be a permanent fixture in your garden.
Garden mums are hardy in zones 5-9 and the one interesting thing about them is that flower initiation is induced by longer nights. Keep that in mind when choosing a location to plant your mums. Avoid street lights or other night lighting situations because the mums would not get the length of darkness required to initiation flower bud formation. The location should provide 6 to 8 hours of sunlight and be well-drained soil. Mums don't like wet feet so avoid low lying areas or heavy soils. Consider improving the planting location by incorporating compost into the soil.
You'll want to plant them in the ground as soon as possible to give them time to root in before the winter. Mums are shallow rooted plants so providing supplemental irrigation if it's dry is needed as is making sure to mulch them with an organic mulch. They are notorious for heaving which is shifting up out of the ground as the ground freezes and thaws and adding a 4-6 inch layer of straw after the ground freezes will help provide needed protection. After they have gone dormant in the fall, don't cut them back. Leave up the growth to help provide an additional layer of protection to help them through the winter.
So let's fast forward to next spring. What do you do now? Fertilize them once a month once growth resumes in the spring with July being the final month of fertilizing. To encourage bushier mums with more flowers you can pinch them back (removing 1-2 inches of growth) this also prevents super leggy mums with few flowers that flop over. The first pinch should be down when the mums are 8-10 inches high, second pinch is around summer solstice (longest day of the year) or by July 4th. If you want even bushier mums you can add another round of pinching in between the other 2. Make sure to provide moisture during the growing season if it's dry.
If your fall planted mums are unsuccessful surviving the winter but you are wanting to still have them in the landscape, consider purchasing mums in the spring. Spring planted mums have a longer time period to establish themselves in the soil improving their winter survivability following the recommendations for winter protection I mentioned above.