killingerscollection

This is a collection about horticulture.

Impatiens Downy Mildew September 15, 2014

Impatiens with downy mildew

Did your once gorgeous flowering impatiens turn into bare looking sticks by the end of the summer? If so you are not alone. Impatiens downy mildew is a fungal-like infection that has been reported across the state this year. Find out more about this disease, how it spreads, and what you can do in the future to prevent another infection.

The symptoms of the infections aren’t as easy to spot as you might think. The first symptoms are leaves starting to appear light yellow or stippled yellow and green. The leaf edges begin to curl downward and appear to be wilted. The tell-tale sign is the fluffy white growth on the underside of the leaves. Often these symptoms are over-looked until the plant begins to lose its blooms and leaves, leaving bare stems. Eventually, the entire stems will begin to collapse and turn soft and mushy. All varieties and hybrids of Impatiens walleriana, common bedding plant impatiens, are susceptible to impatiens downy mildew. New Guinea impatiens, Impatiens hawkerii, are highly resistant as are other bedding plants in different genera that aren’t related to impatiens.

Underside of the leaf. Photo courtesy msue.anr.msu.edu.

The development of impatiens downy mildew is highly influenced by the weather. Wet foliage, cool night temperatures, and moist air all contribute to ideal conditions for this disease development. Plants in heavily shaded locations where the leaves stay wet for extended periods of time will tend to have higher incidence and severity of this disease because moisture promotes infection. Impatiens downy mildew tends to be worse in locations where leaves stay wet for extended periods of time, beds that are densely planted, or in beds that receive overhead sprinkler irrigation, due to the leaves not being able to dry quickly.

It takes perfect environmental conditions for this disease to take hold. The pathogen can be introduced into a garden on infected transplants that aren’t yet showing the symptoms. Additionally, impatiens that are planted into beds that were infected the previous year may also become infected. A close cousin to the pathogen that causes impatiens downy mildew has been found to survive for 8-10 years in the soil.

Impatiens downy mildew can spread throughout the landscape. The pathogen produces spore-like structures called sporangia on the lower surface of the leaves of infected plants. These structures can be splashed short distances or become airborne and travel long distances on moist air currents and spread the infection. It only takes about four hours of a wet leaf surface for sporangia to form. Under hot, dry conditions, infected plants may not show symptoms of disease and produce sporangia on the lower leaf surface.

There are several management approaches for the landscape beds. Avoid planting Impatiens walleriana in those beds that had plants infected this past year. Consider alternative plants in those areas like coleus, caladium, begonia, or New Guinea impatiens. In beds with no history of impatiens downy mildew, I. walleriana can be planted, but take care to inspect and select disease free plants. Once a plant is infected, there isn’t a cure and it should be removed from the landscape. Also pick up any fallen leaves or blooms and consider removing neighboring plants. At the end of the growing season, completely remove all plant material to prevent the pathogen from overwintering.

Changing cultural practices can also help prevent this disease. If possible, reduce the amount of moisture and humidity that the plants are getting. Aim to water the plants in the early morning and provide deep infrequent irrigation to reduce the amount of time the leaves are wet. Space plants out so that there is adequate air circulation between the plants.

Fungicide applications are another option. Most fungicides can help prevent infection, but there aren’t any that will cure the disease once the infection has occurred.

Don’t let impatiens downy mildew stop you from enjoying these shade-loving annuals. Take precautions to ensure this disease doesn’t take hold of your landscape. But if it does, be prepared to try other interesting annuals.

For more information contact Elizabeth Killinger at elizabeth.killinger@unl.edu, 308-385-5088, on Facebook, Twitter, her blog at http://huskerhort.wordpress.com/, or visit the University of Nebraska-Lincoln Extension website: hall.unl.edu.

 

Garden Weeds: A plant out of place… August 14, 2014

Filed under: Garden — Elizabeth Killinger @ 2:53 pm

All things considered, it’s been a good year for the home gardener. No doubt some of you with gardens are being buried by the amount of produce. Before too long the zucchini fairy will start leaving ‘gifts’ on the door steps of neighbors and friends. The weeds are thriving just like the rest of the garden and we still have a long garden season ahead of us. Find out what you can do to keep your garden weed-free up until frost.

The biggest problems for most vegetable gardeners include bugs, diseases, weather, and most commonly, weeds. A weed by definition is a plant out of place. In the vegetable garden, that can mean any plant that isn’t eaten eventually. Proper identification of the plant ensures that you are removing the ‘weed’ and not pulling up the garden crop you worked so hard to get to grow. The best time to control weeds is when they are seedlings, but that doesn’t always happen. It is important not to let the weeds go to seed, which can make future weed problems worst in the long run. One shepherd’s purse plant can produce 38,500 seeds in a single growing season and one redroot pigweed can produce 117,400 tiny seeds in a year.

There are several methods that can be used in the war on weeds. Mechanical control, chemical control, and mulching are three common methods used to combat weeds in the vegetable garden. Mechanical control can mean a wide variety of methods, all of which manually disrupt the growth of the weed. Rotary hoes, wheel hoes, powered garden tillers can work in those areas between wide rows and those areas where weeds are winning the war. Hand pulling or using hand tools may be needed closer to the crop. Pulling early and pulling often is the motto for most vegetable gardeners when it comes to weeds. If the weeds have gotten away from you and they are starting to set seeds, more drastic measures may need to be taken…the lawn mower. Mow off the weeds before their seeds fully mature. Mowing short on a hot summer day is enough to set the weeds back enough to buy some time for you to try to regain control, or even kill them in some instances.

Carefully selected herbicides are another option for weed control in the vegetable garden. An early season choice for the vegetable garden would include preemergence products that contain trifluralin, like Preen Garden Weed Preventer, or corn gluten meal, like in Preen Vegetable Garden Organic Weed Preventer. These products keep the weed seeds from germinating, or sprouting. Use caution in areas where you want to direct seed garden crops as they can also keep your garden seeds from germinating as well.

Herbicide control on already emerged weeds can get be a little more risky. Some post emergence herbicides like those that contain 2,4-D can volatilize into the air and cause damage to sensitive crops like tomatoes, peppers, and potatoes. If you do select a post emergent herbicide for the vegetable garden, be sure that the labeled for use in the garden and follow the label’s instructions.

Monitoring weeds before they get out of control is easier said than done. Watch for weeds, apply preemergence herbicides early in the season, scout throughout the season, and pull weeds often. If all else fails, just remember some weeds are edible making them a tasty addition to the garden.

For more information contact Elizabeth Killinger at elizabeth.killinger@unl.edu, 308-385-5088, on Facebook, Twitter, her blog at http://huskerhort.wordpress.com/, or visit the University of Nebraska-Lincoln Extension website: hall.unl.edu.

 

 

Enjoy Roses: flowers, thorns, bugs, and all July 28, 2014

Filed under: Uncategorized — Elizabeth Killinger @ 1:00 pm

No doubts about it, roses were hit hard this winter. Whether you had hybrid tea roses or the tough-as-nails shrub roses, they all took a beating. Don’t let your roses suffer any more damage this summer, be on the lookout now and catch these common rose problems.

Japanese Beetles

Japanese Beetles

Japanese beetles are a common pest of roses. They will feed on most anything, but they have a love for roses. These insects are related to the May/June beetle and can be a major pest of roses. The immature form of the beetle is a grub that can do some damage to turfgrass. The adults hungrily devour roses and cause the most feeding damage. The front of this beetle is a dark metallic green and the wing covers are a dark tan or coppery color. The main identifying characteristics for these beetles are five small tufts of white hair along each side of the insect. They feed in clusters during the day on leaves or on the blooms. Adult Japanese beetles can cause the leaves to have a skeletonized appearance, ragged holes, or in some instances, the leaves are completely eaten.

Rose Chafers

Rose Chafers

Rose chafers are another beetle pest of roses. The adult beetles are slender, 1/2 inch long, and are light tan colored. They lack the tufts of hair that the Japanese beetles have. The long burnt-orange legs are the distinguishing characteristic that sets them apart, as they clumsily walk around. The adults feed on the foliage and flowers of roses, while the larvae feed on roots of grasses and alfalfa. Adults may feed together and can cause skeletonized leaves or ragged holes in the flowers.        

There are a few ways that you can control Japanese beetles and rose chafers on roses. If the infestation is light, hand picking is an option. Pick the beetles off in the early morning and drop them in a bucket of soapy water. There are also some deterrents that can be used like neem oil. Several insecticides are labeled for control of these pests with active ingredients like carbaryl, acephate, and chlorpyrifos. Keep in mind that these beetles are mobile and often new beetles take the place of those killed by insecticides. Try to avoid applying the products to the flowers or during times when bees are present because they can harm honeybees.

Black Spot on Roses- photo courtesy IANR Pubs http://www.ianrpubs.unl.edu/pages/publicationD.jsp?publicationId=674

Black Spot on Roses- photo courtesy IANR Pubs http://www.ianrpubs.unl.edu/pages/publicationD.jsp?publicationId=674

Some disease names lack imagination. Black spot of roses is one of those. This fungal disease causes the rose leaves to turn yellow then develop black spots, hence the name black spot of roses. The leaves that are affected might fall off, which can affect the appearance of the shrub. It can also reduce plant vigor, cause stunted growth, and increase the chance of winter kill. The fungal spores overwinter on fallen leaves and diseased canes. Rain splash or sprinkler impact easily spreads the spores onto healthy new plant material.    

Prevention is the best method for dealing with black spot. Following good sanitation practices like cleaning up rose beds in the fall will make sure to get rid of any old plant debris that could overwinter spores. Replacing old mulch with new, if black spot was a problem in the past in that location, as well as looking for and selecting rose varieties that are resistant to black spot will help to reduce or eliminate the need for a spray program.

Fungicides are another option for black spot control. For best results, most fungicide applications should be applied preventatively to healthy foliage to keep the leaves from becoming infected. Throughout the growing season, infected leaves should be removed as soon as symptoms begin to appear. On plants with a history of black spot, fungicides can begin to be applied as soon as the foliage begins to emerge in the spring and continued throughout the summer. Read and follow label instructions for application and reapplication recommendations. For best results, a fungicide should be used in combination with good cultural and sanitation practices.

With a keen eye, you can catch these issues before they become a pest in your rose bed.

For more information contact Elizabeth Killinger at elizabeth.killinger@unl.edu, 308-385-5088, on Facebook, Twitter, her blog at http://huskerhort.wordpress.com/, or visit the University of Nebraska-Lincoln Extension website: hall.unl.edu.

 

Is that a Webworm or a Bagworm? July 14, 2014

Filed under: Insects,Trees — Elizabeth Killinger @ 2:00 pm

Webworms, bagworms, are they the same thing? If not, why does it make a difference whether you have a bagworm or webworms? It can make a big difference which insect you have to control and the damage that they cause. Correct identification is key to know how to control these pests.

Fall webworms or tent caterpillars are an occasional pest. They are sometimes called ‘bagworms,’ but using the correct common name will help clear up confusion. They appear as white webbed nests on the ends of branches in cottonwood, crabapple, walnut, and other trees. The caterpillars hide in the webbed nest during the day and feed on the trees at night. The caterpillars cause little harm to otherwise healthy trees. Tree health is not usually affected until more than 50 percent of the foliage is eaten. If there are enough nests, about one on every branch, the tree could be completely eaten. If you can safely reach the nest, use a broom to break up the bag of webworms. Follow up by spraying with a strong stream of water or an insecticide like permethrin (Eight) or Spinosad (Conserve). The nests can also be pruned out when possible. Trees that have heavy infestations this year won’t necessarily have a similar outbreak next year.   

Bagworms on a juniper.

 

Bagworms are a whole different story from webworms. Bagworms will feed on a wide variety of trees and shrubs, but they mainly prefer evergreens, especially junipers, cedars, and spruce. The reason that they are called bagworms is because they spin their own individual cases or bags around them for protection. As the bagworm grows, so does the bag that contains them. They will add leaf fragments to the outside of the bag for camouflage. The bags look like baseball bat-shaped ornaments hanging from the trees. There is one way to know if your cedar tree has bagworms. If you see little cone shaped things on your cedar tree, more than likely you have bagworms, because cedar trees don’t produce cones.

The earliest sign of bagworm injury on junipers is brown stressed needles at the tips of the branches. If the infestation is severe enough, the tree they are feeding on will have a brown tint to it. Heavy infestations of older bagworms are capable of completely defoliating a tree or shrub. This can cause stress to the plant or even kill it if damage is great enough. This is especially true if they have infested an evergreen which is unable to re-grow new foliage until next year. If you have bagworms on any deciduous plant, ones that lose their leaves every year, they are able to re-grow foliage if needed. Just be sure to pick up the leaves this fall and dispose of them.          

There are several options for controlling bagworms. Insecticidal sprays require thorough coverage to penetrate the canopy and contact the feeding bagworms. It is generally preferable to use ground equipment with higher spray volumes and pressures. Aerial applications may fail to provide thorough enough coverage resulting in less than satisfactory bagworm control. The spray has to completely cover the plant, almost to the point the product is dripping off of it. If the bagworms have made their home on a windbreak, the applicator has to be sure to have enough pressure to get product between the two rows of the windbreak. If this area is missed the bagworms that were hiding out there will move and re-infest the rest of the plant. Hand removal is another option for controlling bagworms. After removing the bags, place them in a bucket of soapy water.

There are several options available for insecticidal control of bagworms. Some of the reduced-risk options include Bacillus thuringiensis (Bt), spinosad, or azadirachtin (neem oil) are effective on young larvae and may be needed to be applied repeatedly. Additional insecticidal options include permethrin (Eight), bifenthrin (Talstar), cyfluthrin (Tempo), chlorantraniliprole, carbaryl (Sevin), dimethoate, esfenvalerate, fluvalinate (Mavrik), lambda-cyhalothrin, acephate (Isotox IV), and tebufenozide (Confirm). Depending on the product and size of the insect, secondary applications may be needed.

Be on the lookout now for webworms and bagworms and control them before they make a meal out of your plants.

For more information contact Elizabeth Killinger at elizabeth.killinger@unl.edu, 308-385-5088, on Facebook, Twitter, her blog at http://huskerhort.wordpress.com/, or visit the University of Nebraska-Lincoln Extension website: hall.unl.edu.

 

Tomatoes vs. Herbicide June 17, 2014

Filed under: Garden — Elizabeth Killinger @ 2:43 pm
Tags: , ,

Tomato with herbicide damageYou say tomato, I say tomato…regardless of your pronunciation, tomatoes are a seasonal favorite in the backyard vegetable garden. Tomatoes have their fair share of seasonal issues and problems. Being observant can help you decide what route is best to take.

Weeds are nothing more than a plant out of place. Other people may have more choice words for these pests, but we all try to control them the best that we can. In the vegetable garden weeds seem to grow twice as fast as in the neighbor’s yard. There are several methods that you can use to help control the pesky weeds before they become a major problem. The simplest method that requires the least amount of equipment is hand pulling. This works best on the weeds before they reach full maturity. To make it easier on you, water the area before you try to pull up the weeds. The mud makes pulling easier and allows you to get a bigger portion of the root with each tug. Solarization of the garden is another non-chemical method you can try. Place clear plastic over the area where the weeds are an issue and secure the edges. Allow the weeds to ‘bake’ under the plastic for 45 days in the peak of the summer season, which means you miss out on this years’ gardening season.

Herbicides are another option for controlling weeds. Preemergence herbicides work best to help control pesky annual weeds. These herbicides will also keep garden seeds from sprouting and shouldn’t be used in areas where plants are direct seeded in the garden. Preemergence herbicides are best if they are used in areas that will be transplanted into, the plants have already sprouted and the herbicide won’t affect the transplants. If grasses in the garden are an issue, a product specifically designed to control grass, like Over-The-Top, or glyphosate product, like Round-Up, can help. Apply the products only to the weeds themselves, not the garden plants. Glyphosate is a non-selective herbicide and will damage whatever plant material it is applied to. Be sure to read and follow all label instructions prior to applying the herbicides. Make sure they are labeled for use on the weeds that you have and that they are labeled for use in the garden.

photo 4Use caution when using certain types of herbicides around the garden. Some broadleaf weed herbicides such as 2,4-D are volatile, especially during hot weather, and may drift across the yard or even from adjacent yards in concentrations sufficient to cause injury. If possible, avoid applying this herbicide for weed control during summer months to escape injury to non-target plants. Tomatoes are one of the more sensitive plants to 2,4-D injury. Herbicide drift on tomatoes appears as leaves that are cupped, thickened, distorted or leathery, and which develop an uncharacteristic fan shape. The youngest foliage is often the most sensitive to the drift and will show the symptoms before the older foliage. If herbicide is suspected, inspect other plants in the area. Herbicide injury will typically be found on more than one type of plant. Other herbicide-sensitive plants include potato, pepper, grape and redbud and they will also show twisting or distortion. Whether or not long term injury will occur is difficult to evaluate. There is no way to know how much herbicide the plant received. We cannot recommend that affected produce from vegetables is safe to eat if it was exposed to herbicide drift. This is especially true for those vegetables that were on the plant at the time of the exposure.

With a little bit of caution now you really can have it all. You can control weeds in the garden, have your tomatoes and eat them too.

For more information contact Elizabeth Killinger at elizabeth.killinger@unl.edu, 308-385-5088, on Facebook, Twitter, her blog at http://huskerhort.wordpress.com/, or visit the University of Nebraska-Lincoln Extension website: hall.unl.edu.

 

Fruit Trees for Nebraska May 19, 2014

Filed under: Uncategorized — Elizabeth Killinger @ 8:00 am
Redhaven peach- photo courtesy extension.missouri.edu

Redhaven peach- photo courtesy extension.missouri.edu

Spring is in the air. The apples are blooming, bees are buzzing, and the threat of frost has passed. There is nothing better than the spring blooms on an apple and eating a piece of fruit fresh off your own tree in the fall. There are few rules to keep in mind when selecting fruit trees for your landscape.

The words location, location, location have never been more important than with the site for your fruit trees. The performance of the fruit tree all depends on how well their growing requirements are meant. Fruit trees require full sun, at least 8 hours a day. They also require enough space between the trees so shading isn’t an issue. Low lying areas, or frost pockets, should be avoided. These areas can allow cool air to settle, and increase the risk of frost or cold damage. South facing slopes with some earlier blooming fruit trees, like apricot, should also be avoided. These slopes warm up faster in the spring, which could mean an earlier bloom that is susceptible to frost damage.

The use of the crop is another factor to consider. On average a dwarf apple tree can produce 50 to 150 pounds of fruit and tart cherries can produce 40-120 pounds. The use of the crop, whether it’s fresh, cooking, canning, or freezing, will make a difference in the amount of fruit you can utilize before it goes bad. Start small, you can always plant more trees later.

After the perfect location is selected and the number of trees is decided; cultivar selection is the most important task. Fruit tree cultivars should be selected based upon their vigor, productivity, climate adaptability, fruit quality, disease resistance, and personal preferences. All fruits are susceptible to insect pests and disease organisms. Some cultivars of apples and peaches are productive only under the careful use of a regular spray program of a combination fungicide and insecticide product. Spraying at specific times throughout the growing season may be needed because many pests attack different fruits multiple times. If ‘grocery store’ quality fruit is your goal, be prepared to apply the fruit tree sprays routinely throughout the growing season to protect the fruit on those susceptible cultivars from pests. If less-than-perfect fruits are okay or resistant cultivars are selected, the spray schedule could be omitted.

Apples are commonly infected by cedar apple rust and apple scab. There are several options to preventing cedar apple rust in apples. One option is to remove all cedar trees within a 2 mile radius of the tree. Fungicide applications can also be applied to the cedars, apples, or both routinely when the fungal fruiting bodies are present. The last option, and the easiest when planting new trees, is to select a cultivar of apple that is resistant to those diseases. Some cultivars that are both apple scab and cedar apple rust resistant include Liberty and Enterprise.

Peaches in Nebraska are a fruit that everyone wants to grow. The sad part is that peaches are not long lived in Nebraska. In a commercial setting a peach tree will live, on average, 8 years. They also take a couple of years to become productive and are susceptible to peach tree borer, oozing bacterial canker, and late spring frost damage. If you decide to try a peach, Redhaven, Reliance, and Madison are the most commonly planted cultivars.

Fruit trees can be grown successfully in Nebraska. Proper site and cultivar selection are just a few important considerations to keep in mind when picking out fruit trees for your landscape.

For more information contact Elizabeth Killinger at elizabeth.killinger@unl.edu, 308-385-5088, on Facebook, Twitter, her blog at http://huskerhort.wordpress.com/, or visit the University of Nebraska-Lincoln Extension website: hall.unl.edu.

 

Ants vs Termites May 11, 2014

Filed under: Insects — Elizabeth Killinger @ 8:00 am
Tags: , , ,

 

Spring is officially here. Trees are blooming, grass is greening up, and the insects are beginning to swarm. Ants will begin swarming…or wait are they termites? Knowing the difference between these insects can make a difference in whether you let them be or if you should be concerned.

Positive identification of the pest is crucial in knowing if control measures need to be taken. Both ants and termites can swarm outdoors in the spring; don’t automatically think when you see a swarm of insects that you have termites on your hands. There are a few distinguishing characteristics to help you quickly identify a swarm of ants from a swarm of termites. Ants have two pairs of wings. The front wing is slightly longer than the rear wing. When you look closely at the antenna, they will have ‘elbows’. Another characteristic to look for is the waist. Ants have a pinched waist between their second and third body segments. . Swarming ants can have wings to help them move the colony from place to place. Once they get to a location that they find suitable, they clip their wings off and look like ‘normal’ ants again.

Termites have a slightly different appearance. Termites also have two sets of wings, but both wings in the set are the same length and of equal size. The antenna of the termite is also slightly different than that of an ant. The antenna of a termite is straight, as opposed to elbowed like that of an ant. The waist of the termite is also different. Termites have a broad waist between their second and third body segments.

After properly identifying the pest, you can then select the control method. There are about a dozen ant species associated with homes in Nebraska. In the spring, ants often find their way into homes before food is available outdoors. Once an ant finds a suitable food source, it alerts all of its friends. It might make you feel good to kill the one scout ant, but there will be others. To get a good control of the ant population, you have to control the colony. There are three methods that you can use to control the colony. You can find the colony yourself and treat it. This approach may not be as easy as it sounds, especially if the colony is in the wall or under a concrete slab. Baits are another approach to treating for ants. Most of the ready-to-use baits work well on the sweet-loving ants, but some prefer protein. If the sweet-baits aren’t being eaten or don’t seem to be working, try a protein based bait. The last approach is to contact a licensed pest control company. They are able to apply a perimeter spray to help control the ants.

Termite control is a different story. A swarm of termites on the ground near the house doesn’t automatically mean you have a termite infestation, but it doesn’t hurt to have the home checked by a professional. The products that are on the market for termites should be applied by a licensed pest control operator.

I am sure you never thought you would have to look at the waist of an insect for proper identification, but you will be glad you did in the long run.

For more information contact Elizabeth Killinger at elizabeth.killinger@unl.edu, 308-385-5088, on Facebook, Twitter, her blog at http://huskerhort.wordpress.com/, or visit the University of Nebraska-Lincoln Extension website: hall.unl.edu.

 

 
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