1. Rocky Mountain billbug (also known as Denver billbug) causes damage to Kentuckty bluegrass lawns in western Nebraska. Billbug injury can be mistaken for white grub or sod webworm damage, disease, or drought stress. Newly-hatched larvae tunnel in grass stems, hollowing out the stem and leaving fine sawdust-like debris and excrement. Infested stems discolor and when pulled, readily break away at or near the crown. Subsurface feeding by older larvae can damage root systems, causing lawns to appear drought stressed. Larvae are cream colored, legless with reddish heads. They look like a puffed up rice kernel. Under heavy billbug pressure, turfgrass turns brown and dies. When control is needed, insecticide applications need to be timed for when adults are present in May and June. Rocky Mountain billbug adults are 1/3 to 1/2 inch long brownish-black weevils. They may be observed on sidewalks or monitored using pitfall traps (see link).

How to Sample for Insects in Turfgrass, University of Nebraska-Lincoln
Billbug grubs, University of Nebraska-Lincoln
Billbugs and White Grubs, Colorado State University

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2. Bluegrass billbug is the species that damages turf in eastern Nebraska. When control is needed, insecticides also need to be targeted at adult weevils present from April into June and September into October. Bluegrass billbugs are smaller at 1/4 inch long and also brownish-black. Pit-fall traps are the best way to monitor.

Billbug Bluegrass Billbug, University of Nebraska-Lincoln

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3. White grub preventive insecticides- On turfgrass with a history of white grub damage, the preventive insecticides imidacloprid (Merit) or halofenozide (Mach 2) are recommended applied by mid-July. With our above average early temperatures this year, the recommended application timing this year is slightly earlier. This year, these products are best applied from June 14 (Flag Day) to the 4th of July. Correct irrigation is important to effectiveness.

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4.  Chinch bug damage has been reported in Zoysiagrass in the Omaha area. Buffalograss can be infested as well. Chinch bugs injure grasses by withdrawing sap from plant tissues in the crown area. While feeding, they may inject a salivary toxin that damages plant tissues and inhibits the translocation of water and nutrients. Initially, this feeding results in reddish-purple discoloration of the leaves. In turfgrass, damage appears as patchy areas which turn yellow and dry to a straw-brown color as feeding progresses. For information on detecting and controlling chinch bugs, see:

Chinch Bugs in Buffalograss and Zoysiagras Turf, University of Nebraska-Lincoln

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5. Perennial broadleaf weed control- Homeowners need to avoid applying herbicides when temperatures exceed 80°F as a rule of thumb. However, this is dependent on the species, age of turf, and herbicide. Read and follow label directions for safe and effective applications. The optimum time to apply herbicides for perennial broadleaf weeds is during fall when plants translocate herbicide throughout the plant for increased control. Use spot treatments when treating broadleaf weeds. This is a “greener” option compared to blanket applications of weed and feed products applied to an entire lawn.

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6. Chemical control of winter annual broadleaf weeds like henbit, speedwell and shepardspurse is best done with a postemergence herbicide applied in October. Fall is when the majority of these weeds germinate. By late spring/early summer, they have gone to seed and will soon die. Maintaining a well-managed dense turf and hand-pulling early, prior to seed set, are cultural control methods to use now.

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7. Preemergent herbicide applications- If the first application of preemergence herbicide for crabgrass control was applied prior to mid to late April; or if a turf area has a history of severe crabgrass infestation; a second application at this time will be beneficial in controlling crabgrass. This is true in all years, but especially important this year when we are recommending sequential applications on almost all turf areas given the extended season.

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8. Dollar spot is a fungal disease. It causes four- to six-inch, straw-colored patches on taller cut lawns. Hour glass shaped, bleached lesions with reddish margins on each end are present on leaf blades in or near blighted turf. Shorter cut turf (greens and fairways) develop small (1 to 2” diameter), round, bleached spots about the size of a silver dollar. Dollar spot is most often seen on turf that does not receive adequate fertilization. To limit dollar spot, provide sufficient nitrogen, irrigate correctly to maintain plant vigor and avoid drought stress; irrigate in the early morning hours; and limit traffic and mowing on wet turf. Fungicides are recommended on professionally managed turf, but usually not for home lawns.

Dollar Spot Disease in Turfgrass, University of Nebraska-Lincoln

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9. Summer Patch symptoms are one to two foot, tan colored, circular, crescent, or serpentine shaped patches that usually appear during summer in full sun areas. Tufts of healthy green grass may remain in patch centers. No leaf spots will be found on grass blades. The fungus attacks turfgrass roots in spring. Infected plants may have dark brown to black roots. Control includes proper lawn care practices to reduce stress, overseeding with resistant cultivars, and fungicide applications made in April and May.

Necrotic Ring Spot and Summer Patch, University of Nebraska-Lincoln
Managing Patch Diseases, University of Nebraska-Lincoln
Information on resistant cultivars, National Turfgrass Evaluation Program

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10. Efficient lawn watering involves watering in the early morning when it is less windy and temperatures are cooler; watering at a rate that allows water to infiltrate the soil and not run off: and, moistening the soil to a depth of 4 to 6 inches at each watering cycle and then waiting until the turfgrass shows signs of needing water (footprints left in the grass, bluish-green cast) before irrigating again.

Watering Home Lawns, University of Nebraska-Lincoln.

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11. Leaf scorch in trees appears as a uniform yellowing or browning of leaf edges. Browning may extend between the veins. Scorch indicates leaves are transpiring moisture faster than it is replaced by the roots. We have seen an increase in leaf scorch this year, most likely due to above average temperatures and windy conditions. Leaf scorch occurs for a variety of reasons.

• Young trees with large leaves (i.e. maples) and unestablished root systems, especially those growing on exposed, windy sites, often show leaf scorch.
• Young tender growth, especially lush growth promoted by nitrogen fertilizer, can scorch during hot, windy days even with established root systems.
• Leaf scorch may be a symptom of a root and/or trunk related problem.

Both over-and underwatering may lead to leaf scorch. When this symptom appears, avoid fertilization; check soil moisture for dryness or saturation; then use correct irrigation practices to encourage recovery.

Leaf Scorch, University of Nebraska-Lincoln

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12. Spider mites affect a wide variety of plants from trees & shrubs, to ornamentals & vegetables. Mite populations are promoted by hot, dry conditions. Mites and their webbing can barely be seen with the naked eye. 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 appear as specks moving around on the paper. NOTE: Carbaryl (Sevin) can increase mites by killing their predators.

Spider Mites, University of Nebraska-Lincoln

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13. Ash leaf curl aphids cause the leaves of ash trees to become curled, puckered and sticky with honeydew. When unfurling curled leaves, hundreds of small, soft-bodied, pear-shaped insects may be found. Aphids feed by sucking sap from buds, leaves, and twigs. While the damage is unsightly, leaves continue to photosynthesize. Insecticide control of aphids is not needed for the trees overall health. Aphids are usually controlled effectively by adverse weather conditions such as rainfall; and fungus diseases, insect predators and parasites keep aphids in check naturally. On smaller trees, try washing aphids away with a forceful stream of water before using insecticide sprays.

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14. Soldier beetles on Lindens are massing in very large numbers as they feed on flower nectar and pollen. These beetles are dull orange to dark gold with two black spots on the ends of their wing covers. They are not harmful to plants and no control should be attempted. Soldier beetles also feed on insects such as grasshopper eggs; hence they are beneficial. There are typically two generations per year.

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15. Red-headed ash borer can attack weakened ash, oak, maple, walnut and hackberries. The adult is a reddish brown beetle with horizontal yellow stripes on its wing covers. Larvae are round headed borers. Adults emerge in spring and egg-laying takes place from May until August. Like most borers, red-headed ash borer attacks stressed trees. Reducing stress on trees is the best prevention against borers. If chemical control is used, products containing bifenthrin or permethrin can be applied to trunks and larger branches during the egg laying period or systemics containing imidacloprid can be applied as a soil drench. Imidacloprid needs to be applied about 60 days prior to egg laying to allow time for uptake.

Insect Borers of Shade Trees, University of Nebraska-Lincoln

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16. Oystershell scale attack a variety of plants and are common on lilac. Scale insects attach to twigs and branches, and grow a waxy covering that camouflages them as they feed on plant sap. Branch dieback occurs when high populations of scale are present. Prune and destroy heavily infested branches. Insecticides such as bifenthrin, malathion or Orthene need to be applied to young crawlers soon after egg hatch, usually starting in May, to be effective. Monitor plants in August for a second generation of young crawlers.

Oystershell Scale, University of Nebraska-Lincoln

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17. Needle browning on Spruce is being reported, and there are several possible causes.  In some cases, it is desiccation/drying due to hot, windy conditions this spring. It is another example of leaf scorch. If this is desiccation rather than a disease, needle browning will be uniform from needle tips back and most browning is likely to be seen on the south or west side of the trees. Avoid fertilization and irrigate correctly to encourage recovery.

Rhizosphaera needle cast also causes discoloration and shedding of older spruce needles. Second year needles turn greenish-brown to purple and drop. Disease usually starts at bottom branches and moves up. Treat with chlorothalonil or Bordeaux mixture fungicide in late May or when new shoots are ½ to 2 inches long. Repeat spray in four weeks. Trees that suffered damage in last year's hail storms especially need to be watched.

Finally, Sirococcus Shoot Blight of Spruce causes death of new foliage, and causes branch tips to turn brown and drop needles. Last years’ growth, and sometimes one year old growth, will turn reddish brown and needles drop off leaving branch tips bare. Infected tips may curl into a hook shape. Small black fruiting bodies can be seen on infected shoots. To control, apply chlorothalonil fungicide to infected trees in May when new shoots are one-half to two inches long. Repeat application 3 to 4 weeks later.

Rhizosphaera Needle Cast of Spruce, USDA Forest Service
Sirococcus Shoot Blight, University of Nebraska-Lincoln

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18. Small holes in Cottonwood leaves are mostly likely due to feeding by any number of beetles or beetle larvae, such as a cottonwood leaf beetle. Small holes in leaves are not harmful to trees. The leaves still have enough green tissue for photosynthesis to occur.

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19. Replenishing tree mulch is needed since organic mulch like wood chips decays over time. To replenish mulch, lightly rake through remaining mulch to fluff it; then, apply additional mulch over the top. Mulch layers should only be two to four inches deep and kept six to 12 inches away from the trunk. The wider the mulch ring, the better. Avoid deeper layers of mulch as this reduces oxygen exchange with the soil. Also, fine roots tend to grow in deeper mulch layers and the roots are then killed when the mulch becomes too dry, leading to tree stress.

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20. Watering trees is beneficial when done correctly. Ideally, the soil will remain moist but not saturated to a depth of about 8 to 12 inches when trees are watered correctly. Moisture is critical to root establishment, root function, as well as reducing drought stress; however, adequate levels of soil oxygen are also critical to root growth and function. How much and how often to water depends on the soil type, site conditions, age and species of the tree, and environmental conditions. For wise watering tips, see:

Watering Tips for Trees and Shrubs, University of Nebraska-Lincoln.

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21. Hollyhock rust is caused by a fungus that, unlike many other rust fungi, completes its life cycle on one host. The fungus survives winter in infected plant debris. In spring, spores are rain splashed or wind-blown to leaves. Initial symptoms are yellow to orange spots on upper leaf surfaces; then red to brown pustules develop on lower leaf surface and release orange spores to infect nearby leaves throughout summer. Hollyhock rust can be managed during dry years with cultural controls. Remove all plant debris in the fall to reduce the amount of overwintering fungus. Use healthy transplants or start disease-free seeds each year. Keep plants growing vigorously in a sunny location with good air circulation. Avoid overhead watering. Routinely check hollyhocks for leaf spots and remove infected leaves as they appear. Rust can become severe during wet seasons and can require chemical control. Fungicides like Myclobutanil or Propiconazole must be applied early and applications repeated according to label directions to protect leaves from rust infection.

Hollyhock Rust, University of Minnesota

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22. Phlox Plant Bug feeding occurs on upper leaf surfaces of young phlox leaves and buds. Injury appears as white or pale-green spots that later become yellow-stippled areas. Blossoms may be deformed. In extreme cases, plants become stunted and die. Adult bugs generally have contrasting colors, i.e. orange and black or red and black, sometimes gray and white or yellow; all with black legs. Nymphs are orange or bright red. This insect overwinters in the egg stage with nymphs emerging in early May. Remove infested plant parts. The use of insecticidal soaps, horticultural oils, or systemic insecticides will reduce damage.

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23. Slugs are soft, slimy, slender mollusks, not insects. During the evening, slugs feed on leaves and flowers causing various sized holes. During the day, slugs hide beneath plants, pots, weed mats, boards, or in the soil. Traps are helpful to reduce slug populations. Beer traps, shallow containers of beer sunk in the ground so the top edge is level with the soil, are only moderately successful. A better method is laying moist news-papers, shingles, or boards on the ground overnight. Check beneath these the next morning and kill the slugs. Gritty materials, such as diatomaceous earth, can be scattered on the soil surface to reduce slugs. For chemical control, baits containing metaldehyde or iron phosphate are available. As with all pesticides, label directions must be followed carefully. For best control, apply these products on a warm, clear night during dry weather. Place them under boards or traps to help protect birds and pets. Two or more treatments at 5 to 7 day intervals may be needed for adequate control.

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24. Hosta Virus X (HVX) is a virus infecting many Hostas. Symptoms range from stunting to leaf puckering, ring spots and other odd leaf colorations. While this disease does not kill plants, it spreads prolifically and infected plants should be destroyed. The virus is transmitted primarily through propagation of the plants or mechanical injuries.

Contact of the infected plant's sap, with sap of a healthy plant will infect the new plant. This can happen whenever cuts are made and tools or hands are not disinfected afterwards. Dividing hostas, removing bloom scapes, removing leaves, stepping on them, even accidentally mowing over them can spread the virus. There is no control. Plants suspected of having HVX should be destroyed.

Hosta X Virus, Ohio State University

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25. Water wisely & timely to avoid overwatering which wastes water and stresses plants; and to avoid underwatering which also stresses plants. For wise watering practices, see:

Landscape Water Conservation, University of Nebraska-Lincoln

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26. Flower beds & lawn irrigation- Most flowers do not require the same amount of water, or as frequent irrigation, that automatic lawn irrigation systems are set to apply. If a lawn irrigation system is also watering flower beds, overwatering is occurring. Overhead irrigation can also lead to fungal diseases and root rots. Zone watering is a wise watering practice. This involves grouping plants with similar watering needs together and then watering that “zone” for the needs of those plants. Also keep in mind that perennial and annual flowers have different water needs. For the most part, established perennial flowers require less frequent irrigation than annual flowers. Ideally, perennials are watered separate from annuals.

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27. Hardiness zones indicate the coldest temperature a plant can survive during winter. It is important to know what hardiness zone you live in and to select perennial flowers, trees and shrubs hardy to that zone. Most experienced nursery and garden centers will only carry hardy plants, but some exceptions may occur.  It pays for gardeners to do their own research to make sure the plants they buy will be able to survive in their landscape.

Hardiness Zone Map

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28. Mums are setting blossoms early this year. To delay blooming, and to increase the number of blossoms, pinch out the top three to four inches of each stem. This will remove flower buds that are developing, increase branching, and the number of blooms. Stop pinching mums by the end of June or blooming will be delayed too long in late summer or fall.

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29. Divide perennials in fall- Most perennial plants need periodic division to maintain their vigor and achieve maximum flower production. This may need to be done annually, as with hardy chrysanthemums, but is usually only necessary every three to four years. Some perennials, such as babys breath (Gypsophila paniculata), should never be divided. Plants that bloom from mid-summer to the fall, like chrysanthemum, aster, or coneflower, are best divided in the early spring, before much new growth has begun. Perennials that bloom in the spring or early summer, such as peony or creeping phlox, should be divided in the fall, or after the foliage dies. The exceptions to this rule of thumb are iris and daylilies, which should be divided immediately after flowering.

The time of year when perennials are divided is a major factor in determining the success of this procedure. Summer conditions have gotten too warm, in most cases, for successful division to be done now.  Instead, gardeners should wait until September to divide spring-blooming perennials. 

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30. Indicator plants for herbicide drift are plants that are more sensitive to herbicides. Some indicator plants in Nebraska are tomatoes, grapes, hackberries and Eastern redbud. Often, herbicide damage in the form of leaf curling, cupping and vein distortion is noticed first on these plants. If herbicides are the cause of the damage, less sensitive plants will show similar but less severe signs of herbicide damage. Avoid herbicide damage to nontarget plants by only using herbicides when they will be effective in controlling weeds, spot treating weeds rather than making blanket applications, and following all label directions for application. Do not apply herbicides when temperatures are too high and windy conditions exist. Applying herbicides on extremely calm days is unwise either, because herbicide particles may hang in the air for extended periods of time.  Very light wind movement is ideal for managing herbicide drift.

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31. Tomato early blight is a fungal disease that begins as tan leaf spots on lower leaves, then works its way up the plant causing leaves to die. To reduce early blight, select resistant tomato varieties. Avoid overhead irrigation and increase air circulation around plants with proper spacing and caging. Mulch around plants to reduce fungal spores splashing from the soil onto lower leaves. Avoid planting tomatoes in the same area each year and practice fall sanitation to reduce overwintering fungus. Severely infected plants are best pulled and destroyed. This disease can be reduced with fungicides labeled for use on tomatoes. For the best results on susceptible plants, applications need to begin as soon as symptoms first appear on lower leaves and applications repeated every 7 to 10 days.

Early Blight and Septoria Leaf Spot of Tomatoes, Kansas State University

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32. Bacterial stem rot, caused by the bacteria Erwinia carotovora subsp. carotovora, is becoming active in vegetable gardens, particularly on tomatoes and potatoes.  Plants usually become infected through wounds caused by removal of suckers, staking, trellising or pruning.  Symptoms are often first seen as wilting of affected plants.  The pith of affected stems disintegrates, resulting in hollow stems.  Pinching the stems can locate the hollow section.  Stems develop a wet, slimy rot.  

This bacteria has a wide host range including most fleshy vegetables.  It survives easily in the soil and in surface water. A related bacteria, Erwinia carotovora subsp. atroseptica, affecting potatoes only survives in the soil for one year unless they are contained within diseased tubers or other plant debris.  Disease development is favored by high humidity and warm conditions.

Plant only certified disease-free potato tubers in spring.  Avoid irrigating with surface water or wounding plant stems.  Rogue out infected plants.

Blackleg, Aerial Stem Rot and Tuber Soft Rot of Potato, Ohio State University
Erwinia Hollow Stem and Soft Rot,  University of Florida

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33. Blossom end rot is a common problem of tomatoes, but also affects peppers, eggplant, squash and watermelon. It appears as a flat, dry, sunken, brown rot on the blossom end of fruits caused by calcium deficiency in the fruit. Rarely is there a lack of calcium in the soil. Blossom end rot occurs when plants cannot pull calcium up quickly enough for developing tissues. Calcium must be dissolved in water to move within a plant, so dry soils can increase the problem. Drought stress, low daytime humidity, high temperatures, and rapid vine growth favor blossom end rot. Applying calcium to the soil or to the plant is not beneficial. Instead, maintain a consistently moist but not saturated soil; use organic mulch near the base of plants; and avoid excess nitrogen fertilization.

Blossom end rot, University of Nebraska-Lincoln

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34. Vegetable garden weed control includes tillage, hoeing, hand-weeding and the use of mulch. In cases where a gardener has difficulty keeping up with weeding, mulch is especially important. In some cases, the use of Preen labeled for vegetable gardens may be justified. Preen needs to be applied to weed- and mulch free soil and watered in to be effective for about four weeks in controlling seedlings as weed seeds germinate.

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35. Common stalk borer- tomato, pepper.  Common stalk borer attacks over 100 species of plants including flowers, tomato, pepper, corn, rhubarb, hibiscus, and broadleaf weeds. The stalk borer adult is a dull, grayish-brown moth. Young larvae are brownish-purple with three prominent white stripes at the front and rear ends of the body. The stripes are interrupted by a dark purple to black area at mid-body. Full grown larvae are a uniformly dirty gray color and up to 1 1/2 to 2 inches long. Plant symptoms include stunting, wilting or dieback. Control by controlling weeds and using good sanitation practices. Insecticides are only effective if applied before the borer enters the stem.

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36. Squash bugs are the most damaging insect pest of pumpkins and winter squash. The adult is a brownish, shield-shaped bug about 5/8 inch long and 1/3 inch wide. Adults are very difficult to control; hence plants must be monitored closely for squash bug eggs and young nymphs to effectively control this insect. Eggs are brick red and found on leaf undersides in the V made by veins. Young nymphs are gray and tear drop shaped. Scout plants often for adults, eggs and young nymphs. Hand-pick adults and squish egg masses. When nymphs are present, carbaryl (Sevin) or permethrin can be applied for control in home gardens.

Squash Bugs, University of Nebraska-Lincoln

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37. Strawberry bed renovation is important to promote fruit production and reduce diseases. Once harvest is complete, leaves can be mowed to within one inch of the crown and plants thinned by narrowing rows to 10 to 15 inches wide and thinning plants by removing older plants and very young plants. After thinning, there should be about three plants per square foot. Once thinning is completed, fertilize with an all-purpose fertilizer and water adequately for the remainder of the summer. If needed, thin plants again in September.

Renovation of Strawberry Plantings, University of Nebraska-Lincoln

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38. Strawberry leaf spot symptoms begin as round, purple spots about 1/8" to 1/4" in diameter. Leaf spot centers become white to gray in color as the disease progresses. Spots may eventually coalesce, causing large portions of infected leaves to appear red or purple. Leaf spot does not usually cause serious damage to plants. If infection is severe, the disease could kill leaves, weaken plants, or reduce fruit production. Control of leaf spot involves using the following cultural practices. Planting disease resistant varieties in full sun and where there is good air circulation to reduce leaf moisture. Maintain row widths from 18 to 24 inches and thin beds to avoid dense plantings. Avoid overhead watering. Remove all infected plant material after harvest to reduce fungal spores, and renovate beds annually. Fungicides such as Captan or copper may be used if leaf spot has been a problem in previous years. Read the label carefully and apply only as directed.

Leaf spot and Leaf Scorch of Strawberries, University of Minnesota

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39. Bed bugs and bat bugs are very similar in appearance and easy to mistake for one another without training on how to distinguish between them. Both bugs can be found in Nebraska. Bed bugs feed on humans. Bat bugs feed on bats and some birds. It is important to distinguish between the two as control methods and the cost for control differs greatly. Ideally, take suspected bed or bat bugs to a local Extension office for positive identification. The following is a link to information about how to distinguish between the two.

Managing Bed Bugs, University of Nebraska-Lincoln

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Seasonal information for Nebraska's green industry professionals.