1. Winter injury to turf areas-  Do not confuse winter injury to turfgrass for a disease or insect problem and make an unnecessary pesticide application. Our unseasonably warm and open winter has increased desiccation injury to cool-season turf on lawns, sports turf, and golf courses in western Nebraska. Desiccation occurred when the roots could not supply enough water to the dormant plants to keep up with the amount of water lost through the leaves and crowns. Desiccation injury is usually greatest on exposed or elevated sites, sandy soil areas, and areas where surface runoff is great. Overseed damaged areas and use good turf maintenance practices. If a preemergence herbicide has been applied to the turf, seeding will need to be delayed until late August into early September.

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2. Sod webworm overwinter as partially grown larvae. In spring, they move to the surface and feed until mid to late May when they pupate and emerge as adults to mate and lay eggs for the next generation. Overwintering larvae typically do not cause enough turf damage to warrant control during spring. When overwintering infestations are high, some damage may occur to lawns in spring. This year, damage is being reported in the Panhandle. The close clipping of grass blades by sod webworm does not kill turfgrass directly but exposes the crown to heat stress; thus, injury is much worse during hot, dry weather. If damage is not too severe, lawns will recover from spring feeding without the use of a pesticide treatment.

If webworm is suspected, part the grass with your index fingers to look for small green pellets, the larvae’s excrement. The caterpillars have dark heads and light-brown spots on greenish-gray bodies, but can be difficult to find. In spring, feeding usually stops by late May when larvae reach maturity and pupate. Moths then emerge to mate and lay eggs for the next generation. It is this generation that typically causes turf damage if populations are high enough. Monitor lawns in June for buff colored moths flying low over the lawn and again in August. Seeing moths fly up while mowing or walking around the lawn does not necessarily mean larvae will cause damage. The adult moths can fly considerable distances and may be coming from other infested areas.

If you suspect sod webworm but are unable to find the larvae or their frass, use a soap disclosing drench. Mix two gallons of tap water with two tablespoons of liquid dishwashing detergent. Sprinkle this mix over one square yard of affected turf. Within a couple of minutes, flesh-colored, spotted larvae will wriggle to the surface. If 10 to 15 webworm larvae are found in one square yard of turf, a pesticide application is warranted. If fewer webworms are found, practice good turf maintenance to reduce/prevent damage.

Sod Webworms, University of Nebraska-Lincoln

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3. White grubs- Two-year grubs (May/June beetles) and annual grubs (masked chafers). Damage initially appears as patches of discolored grass, similar to drought stress. On examination, white grubs will be found beneath the sod. If five to eight grubs can be found per square foot, insecticide control may be warranted. This year control is recommended with an application the third week of May to first week of June with imidacloprid (Merit) or halofenozide (Mach 2). Correct irrigation is important to effectiveness and turfgrass recovering.

White Grub Management, University of Nebraska-Lincoln

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4. Seeding buffalograss- Late spring is the optimum time for establishing buffalograss, but it can be established successfully until mid-August if adequate irrigation is available. In spring, seeds will not germinate until soil temperatures reach 60°F, usually after May 15 in eastern Nebraska and May 31 in western Nebraska. This year, seeding can be done earlier. For Nebraska as a whole, seeding by June 1 is a good target date if the goal is to have a full stand by September. For successful seeding of any turfgrasses including buffalograss in spring, irrigation is critical throughout the summer as is weed control. For detailed information on Buffalograss cultivars and establishing buffalograss in Nebraska, refer to the NebGuide Establishing Buffalograss Turf in Nebraska, University of Nebraska-Lincoln. For herbicide recommendations, refer to Herbicide Tolerance of Buffalograss.

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5. Powdery Mildew appears as a white, powdery growth on the surface of grass blades, typically in shady areas with little air circulation. This disease rarely causes more than a cosmetic whitening of the grass blades. Reducing shade and improving air circulation are the most effective control methods. Introducing shade tolerant varieties of Kentucky bluegrass or tall fescue may help. A fungicide application is usually not justified on a home lawn.

Powdery Mildew, UNL Turf iNfo

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6. Ascochyta Tip Blight- Patches or large areas of lawn suddenly turn straw or tan color; resembling drought stress. Leaf blades have bleached white tips and the blade is constricted where dead tissue merges with green tissue. Considered a minor disease related to environmental and poor management stress. Turfgrass usually recovers in one month or less without treatment. Fungicides are generally not recommended or needed.

Ascochyta Leaf Blight, Colorado State University Extension

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7. Slime molds sometimes look like dog vomit (hence the name dog vomit fungi) and can come in many bright colors, while others appear as grayish masses on turf leaf blades. Symptoms of leaf blade smile molds may be seen as irregular patches of discolored turf ranging in size from several inches to several feet in diameter. Some slime molds feed on decaying material and are often found in mulched ornamental beds, while others use turf leaf blades strictly as a structure to grow on. No treatment necessary.

Slime Molds on Turfgrass, Ohio State University

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8. Birds feeding in lawns triggers questions like “Do I need to apply an insecticide to my lawn to control grubs if birds are feeding in my lawn?” There are a number of insects along with earthworms that birds feed on. What they are feeding on may or may not be a turf pest. It is important to be familiar with the life cycle of turfgrass insect pests to know when a damaging stage may be present. If it is the correct time of year for a specific pest, it is important to scout for the actual insect to determine if they are present in high enough numbers to cause damage. While bird feeding could be an indication of a turf pest, do not apply an insecticide for control without first confirming the presence of a damaging pest population.

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9. Tiny pin-holes in Linden tree leaves are being reported in the Omaha area. These are mostly likely caused by small Linden Loopers, a type of inchworm. The caterpillars have a yellow underside and the tops are streaked with black, blue and yellow linear lines. Small pin-holes and low populations of Linden Looper will not cause long term damage to Linden trees. Continue to monitor the tree for loopers and feeding damage, but otherwise hold off on a control measures other than to pick loopers off of small trees.

Linden Looper, Colorado State University

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10. Bagworms- Monitor evergreens for the presence of young bagworms. Egg hatch is likely to occur earlier this year. Bagworms overwinter as eggs inside of small, one to two inch long, brown bags attached to trees. In a typical year, most eggs hatch by mid-June and this is the time when insecticides are applied since they are most effective when bagworms are less than one-half inch long. With unseasonably warm weather, egg hatch is likely to occur earlier this year. If young bagworms are found, low-risk insecticides to apply are Bacillus thuringiensis (Bt), spinosad or neem oil and insecticidal soaps. Low-risk products need to be used when bagworms are less than one-half inch long and repeat applications are made. Regular risk insecticides to apply for bagworms include acephate, bifenthrin or permethrin. Bagworms can also be picked off as they are found. Removal during winter will reduce overwintering eggs.

Bagworms, University of Nebraska-Lincoln

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11. Hawthorn leafminer create sigmoidal or S-shaped tunnels or brown areas on leaves caused by larvae feeding within leaves. By the end of May, larvae leave their mines and pupate within the soil. There is one generation per year. No control is effective once leaf minors are inside leaves. Control is rarely needed.

Hawthorn leafminer, Purdue University

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12. Euonymous scale Infested leaves turn yellow, then die and drop off. Undersides of leaves and stems are covered with a brown or white scale. Scale insects feed from beneath a protective scale, removing plant sap from stems and leaves. Controls are most effective when the insect is in the crawler stage, usually in May to early June and late August to early September (second generation). Monitor for the presence of crawlers by wrapping a few stems with black electrical tape, with the sticky side facing out, near present scales. Crawlers are yellowish to orange. When in the crawler stage, control with insecticidal soaps. Systemic insecticides are also effective. Read and follow label directions for effective application. Prune and remove heavily infested branches to the ground.

Euonymous Scale, University of Nebraska-Lincoln Extension

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13. Ash flower galls are clusters of light green (broccoli-like) galls on seedless (male) ash trees. The galls eventually turn hard and black and remain on trees over winter. They are unsightly but harmless. The galls are caused by the ash flower gall mite feeding on male flowers. Control is not needed.

Ash Flower Gall, Kansas State University

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14. Maple bladder galls are harmless and require no control. They appear as raised, green, bladder-shaped galls or bumps that turn red, then black, on the upper surface of red and silver maple leaves. Leaves covered with galls may curl and drop off. The galls are caused by a small mite feeding on the leaves as they develop in spring. Like most leaf galls, maple bladder gall does not threaten tree health. Control is not practical or needed.

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15. Tent caterpillars- Eastern tent caterpillar, and similar species, can be found feeding on the foliage of flowering fruit trees (plum, wild plum, hawthorn), and other shade trees such as maples and oaks.  These dark-colored caterpillars have a white stripe down their back, and are the larvae of reddish-brown moths.  Egg masses overwinter in affected trees, and caterpillar hatching occurs about the time wild cherry buds turn green in the spring. The larvae stay in groups, and build a small silken web "tent" in a tree crotch for protection from the elements and predators. Almost blind, they leave the tent to feed on leaves during the cooler parts of the day, leaving a silk dragline as they move about the tree.  Caterpillars feed for about 6 weeks, followed by pupation and emergence of adults that lay eggs for the following year's insects.  There is only one generation per year.

Defoliation injury is most damaging to small trees, and is rarely more than an aesthetic problem in larger trees.  Defoliation stresses trees, increasing their susceptibility to secondary pests and diseases and reducing fruit production. Small trees may be weakened only after 3 plus years of greater than 50% defoliation.

Prune egg masses out of trees in fall, or break up webs with a broom in spring when they appear.  In tall trees, break up web masses with a strong jet of water.  Removing webbing makes the caterpillars vulnerable to predation, and usually provides good control.  Pesticide applications can be made, but will have limited effect unless it penetrates the web.  Recommended products include BT (Bacillus thurengiensis) and permethrin.

Eastern Tent Caterpillars, University of Nebraska

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16. Iron chlorosis causes tree leaves to turn yellow while the veins remain green. Browning along leaf edges and between veins, and twig dieback are additional symptoms. In the Great Plains, iron chlorosis is most often due to an alkaline soil pH. In such soils, iron becomes less available to some plants like pin oak, silver and red maple, and ornamental pears. Other causes of chlorosis are over-watering, over-fertilizing, root damage, and manganese deficiencies. The addition of iron to the soil or through trunk injection can temporarily correct iron chlorosis.

For recommendations, refer the Nebraska Forest Service pamphlets on correcting chlorosis.

• Chlorosis of Trees in Eastern Nebraska
• Chlorosis of Trees in Western Nebraska

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17. Hail damaged trees- If hail stripped leaves from trees, otherwise healthy trees will develop secondary leaves and most will be fine in the long term. Avoid fertilizing storm damaged trees.

Storm Damage Series, Nebraska Forest Service

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18. Wind tatter on tree leaves- Warm, windy conditions during spring can tear young tender leaves causing them to appear torn and tattered. This may be confused by some homeowners for insect damage. It is important to confirm the presence of an insect pest before applying an insecticide for treatment. Do not assume torn leaves are due to insect feeding. Wind tattered leaves are not a health threat to trees. If needed, healthy trees will produce additional leaves.

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19. Scouting for borers- Several species of wood boring insects damage trees and shrubs. Many of these require carefully timed management programs. To aid in identification of borers and/or their damage, know what signs and symptoms to look for and when to look for them. A new publication is available and covers the biology and management of wood borers in Nebraska along with colored photos of borers.

Download a copy at: Insect Borers of Shade Trees and Woody Ornamentals

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20. Rose slugs cause rose leaves to become skeletonized and turn brown. Slugs are the larvae of rose sawfly, a small, dark, non-stinging wasp. Sawfly larvae are light green with yellowish-orange heads. Look closely to find larvae. If not found, there is no reason to treat as they have already moved on. Most garden dusts or sprays will work. Insecticidal soaps, the low risk control option, must contact sawfly larvae to be effective.

Rose Slugs, University of Nebraska-Lincoln

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21. Black spot of roses causes small black spots on leaves with yellowing and defoliation. Severe defoliation can eventually lead to plant death. The best control for black spot is planting resistant cultivars in an area with good air circulation and full sun, avoiding overhead irrigation, and practicing good sanitation in the fall. If a fungicide is used, they need to be applied from leaf emergence in spring through July. A low-risk control option research has shown to be effective is the application of a baking soda and insecticidal soap mix. Cornell University found that using 1 tablespoon of baking soda per gallon of water and a few drops of insecticidal soap helped to prevent black spot. They cautioned to use it on a trial basis as some plants may be sensitive to the baking soda resulting in leaf injury. Apply it on few leaves to test its phytotoxicity. If used, apply the mix about once every 3-4 days.

Black Spot of Roses University of Nebraska-Lincoln

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22. Rose rosette is a disease found on multiflora (wild) roses and cultivated roses. It is thought to be caused by a virus although this has not been confirmed. The pathogen is transmitted in sap through grafting with infected plant material and by pruning. Eriophyid mites are also suspected as vectors, but this also has not been proven conclusively. Plants infected with rose rosette may show a combination of symptoms including rapid stem elongation, leaf distortion, leaf reddening, yellow mosaic patterns on leaves, thickened stems, smaller than normal leaves and excessive thorn production. Plant death occurs within one or two years of infection. There is no control of rose rosette. Removal and destruction of infected plants is the only means of control in ornamental plantings. When pruning, clean pruners with a disinfectant between each plant.

Rose Rosette Disease, Kansas State University

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23. Leaf cutter bees on roses- Perfectly round holes in rose leaves or on leaf edges are made by leaf cutter bees gathering leaf material for nest making. These holes are harmless to the roses. Leaf cutter bees are a very important pollinator. Do not apply insecticides to roses when these round holes appear. On a few occasions, the bees may tunnel into canes and cause stem dieback; however, the damage compared to the benefit of these pollinators does not justify control. To prevent tunneling into rose canes, seal the pith (stem center) after making pruning cuts with a drop of white glue.

Leaf Cutter Bees, Colorado State University

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24. Rose chafers are scarab beetles about 3/8 inch long, slender, and light tan to grayish. Adults feed on rose flowers and foliage. Inspect roses for skeletonized leaves and adult beetles. Hand pick beetles if the infestation is light. The insecticides carbaryl (Sevin) and acephate (Orthene) will control the beetles. However, these beetles are quite mobile and new beetles may replace those killed by insecticides.

Leaf feeders of roses, University of Minnesota

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25. Spider mites affect a wide variety of plants from trees and shrubs to ornamentals and vegetables. Red spider mite populations are encouraged by hot, dry weather and we could see increased damage if conditions remain warm and dry. Mites and their webs can barely be seen with the naked eye. Monitor for mites by watching for symptoms. Mites feed by sucking plant juices with piercing-sucking mouth parts, causing white or yellowish specks on leaves; then off-green to bronze discoloration. Controls range from hosing down plants with a strong spray of water (syringing) to using insecticidal oils or soaps; or using insecticides such as Kelthane, malathion, Cygon or Orthene when mites are active. Tap a branch over a white sheet of paper to monitor for active mites. They will appear as specks moving around on the paper. NOTE: Carbaryl (Sevin) can increase mites by killing their predators. Avoid the use of Carbaryl or Permethrin for controlling mites.

Spider Mites and Their Control, Ohio State University
Spider Mites, Colorado State University

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26. Botrytis blight is a wide-spread fungal disease affecting many ornamental plants. Occurring in wet or humid weather, a tan to gray fuzzy mold develops on affected plant parts. Blight of coneflowers and peonies is common. Sections of the affected flowers become brown or black and fail to develop. Avoid overhead irrigation and provide maximum air circulation around plants to minimize the problem.

Botrytis blight or Gray Mold of Ornamentals, University of Illinios Extension

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27. Thrips are very tiny, sap-sucking insects that get inside flower buds and cause damage. Infested buds do not open or open partially with damaged petals. Thrips are difficult to control once inside unopened buds where insecticides cannot reach. Malathion and insecticidal sprays control thrips on leaves and opened flowers. A systemic insecticide may help. For best control, apply an insecticide before or just as flower buds form. Thrips infest many flowers including gladiola, rose, coral bells, iris, and many more.

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28. Hail damaged perennials- High winds and hail result in shredded leaves of Hosta and other perennials. While the damaged leaves of most perennials can be pruned away and will be replaced by new growth, this is not the case with Hostas. While these leaves are not as attractive, as long as they remain green they are photosynthesizing and benefiting the plant. It is best to leave torn Hosta leaves in place. If they turn yellow or brown, then prune out these individual leaves.

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29. Grass control in flower beds- Perennial weedy grasses, such as brome grass, are difficult to control in flower beds. Other than hand-pulling and mulching, the herbicides sold as Grass-Be-Gone or Over the Top can be applied post-emergence to weedy grasses and provide decent control. Note these products contain a surfactant and it is not necessary to use a surfactant, commercial or dish soap, with these products as burning of desirable plants may occur. Be careful in mixed beds with ornamental grasses, contact of these products to desirable ornamental grasses will cause injury or death.

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30. Hardening-off bedding plants- After buying transplants, do not abruptly introduce them from indoor to outdoor growing conditions. Gradually harden or toughen plants before planting them in the garden. Harden off gradually, so that seedlings become accustomed to strong sunlight, cool nights and less-frequent watering over a 7-10 day period. On a mild day, start with 2-3 hours of sun in a sheltered location. Protect seedlings from strong sun, wind, hard rain and cool temperatures. Increase exposure to sunlight a few additional hours at a time and gradually reduce frequency of watering, but do not allow transplants to wilt. Avoid fertilizing. Once transplants are hardened off and planted outdoors, use a weak fertilizer solution to get transplants growing again and to help reduce transplant shock.

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31. Grass clippings as mulch in the vegetable garden- Read the label. Many herbicide labels now have more conservative recommendations; stating grass clippings from lawns to which a herbicide has been applied should never be used as mulch. If this is stated on the label, it must be followed. If the label does not state this, our general recommendation has been to wait until after at least 3 to 5 mowings before using the clippings as mulch; however, it would be safest not to use clippings as mulch

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32. Asparagus beetles- Two types of asparagus beetles may damage plants in Nebraska gardens.  The common asparagus beetle is about 1/4" long, bluish-black with 6 creamy-white spots on it's back.  The spotted asparagus beetle is 1/4" long, reddish-orange in color with black spots.  Both overwinter in sheltered locations, such as loose bark flaps on tree trunks, or in the hollow stems in old asparagus stems. 

• Common asparagus beetle adults appear in the garden as new asparagus spears emerge in spring, and lay dark brown, oval-shaped eggs on the tips of spears.   After feeding, larvae fall to the soil to pupate.  The second generation adults emerge in about a week.
• Spotted asparagus beetles emerge slightly later, being active from mid-May to late July, laying oval-shaped, greenish eggs. Only one generation occurs each year. 

The larvae are light gray slug-like caterpillars with black heads, and  feed on the developing spears for about two weeks.  Feeding causes browning or scarring of leaves and stem sections, and may cause spears to bend over like a shepard's crook.  Severe defoliation can weaken plants. 

Minimize overwintering sites through good garden sanitation.  Handpicking adults and larvae can be effective in small plantings, or scout and remove eggs.  Heavy infestations may warrant a pesticide application.  Refer to the publication below for chemical recommendations.

Asparagus Beetles in Home Gardens, University of Minnesota Extenion

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33. Cole crop insects- Cole crops such as cabbage, cauliflower, broccoli, kohlrabi and kale are often attacked by imported cabbageworm and cabbage looper as well as other insect pests. After planting, inspect plants at least once a week. Check both sides of leaves. When caterpillars or their feeding damage are found, controls include hand-picking the caterpillars and dropping them in a bucket of soapy water, applying the low-risk insecticide Bacillus thuringiensis (Bt), Neem or Spinosad when caterpillars are small, or applying a conventional insecticide such as permethrin, carbaryl (Sevin), or bifenthrin. These are generally longer lasting but kill a variety of insects, including natural enemies. Practice good fall sanitation. Floating row covers can also prevent adult moths from laying eggs on plants; however these lightweight fabrics must be put into place prior to the presence of moths.

Caterpillar Pests of Cole Crops in the Home Garden, University of Minnesota

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34. Squash bugs are a serious pest of winter squash and pumpkins. They feed on leaves and fruit with piercing-sucking mouthparts leading to wilting and browning of leaves and entire plants. Overwintering adults, brownish-black, 5/8 inch long shield shaped bugs, emerge in spring. They lay red eggs in cluster on leaf under-side. These hatch into nymphs that are grayish and tear-drop shaped. Monitor plants closely for all stages of squash bug. Early control is vital to preventing plant damage. Hand-pick eggs and adults when found. Home gardeners can spray or dust leaf undersides with Carbaryl (sevin) as soon as vines begin to run and repeat application as recommended on the label. For control in commercial vegetable production , see the publication below from University of Minnesota. 

Controlling Squash Bugs, University of Nebraska-Lincoln
Squash Bug Management, University of Minnesota

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35. Grasshoppers- As long as conditions remain warm and dry, there is a good chance grasshopper populations will be high this summer across the state. Effective control includes treating egg hatching areas (roadsides and weedy areas) at egg hatch when grasshoppers are young. Adult grasshoppers are difficult to control. Be prepared by reading the Grasshopper Control NebGuide.

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36. Spring miller moths- Millers are abundant around homes this time of year. They are most likely one of the spring miller moths, such as armyworm moths, that typically feed at night on the nectar of flowering trees and shrubs. They do not cause damage, unless you smash them on the wall and create a stain. They are usually around in large numbers for a short period of time as they migrate west, but can become a nuisance. Other than turning off night lights, no control is needed or recommended.

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37. Sustainable Pest Control may be referred to as organic gardening. Interest in environmentally friendly control methods are increasing. Sustainable pest control follows Integrated Pest Management (IPM) which UNL Extension promotes. It is not achieved with the use of one “organic” product or method, but rather a combination of cultural, mechanical, biological and low impact chemical controls. Sustainable pest control starts by selecting the right plant for the location; then providing best management practices for healthy plants that are less susceptible to pest damage. Plants must then be monitored often and closely for early signs of disease or insect pests. When pests are found, positive identification is important to determine if the pest is harmful and if control is even needed. When control is needed or desired, the best control options are usually a combination of methods including:

• Mechanical or physical, i.e. hand-pulling or hoeing weeds and syringing plants with a spray of water to knock off mites
• Cultural, i.e. the use of disease resistant cultivars and correct care practices such as avoiding overhead irrigation to reduce disease infection
• Biological, i.e. encouraging and/or introducing beneficial insects in the garden or the use of products like Bacillus thuringiensis, (Bt).
• Chemical, i.e. conventional products like Carbaryl or permethrin or low impact products such as horticultural oils and insecticidal soaps

Integrated Pest Management, Ilinois State University

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