Enter to win a copy of "The Well-Tended Perennial Garden" by Tracy DiSabato-Aust

Hort Update for the week of 8/25/08

Current Problems:	Major Symptom:
Lawns
1. White grubs	Good growing conditions for turf resulting in reduced calls
2. Chinch bugs	Browning of buffalograss and zoysiagrass turf
3. Brown patch	Roughly circular patches of brown and dying grass
4. Rough bluegrass, Poa trivialis	Pale green patches of grass; may be starting to turn brown in lawns
5. Yellow nutsedge	Pale green to yellowish, 3-ranked, triangular shaped leaves
Trees & Shrubs
6. Two-spotted spider mites	Speckling, bronzing or scorching of leaves
7. Zimmerman pine moth	Dead and dying branches in upper half of pine trees
8. Cytospora canker	Dieback of branches or tree tops. Resin oozing from cankers
9. Sphaeropsis tip blight of pine	Brown or stunted shoot tips. Branch dieback.
10. Bagworm	Larvae pupating; control with insecticide unlikely to work now
Landscape Plants
11. Aster yellows	Distorted flowers. Remove and destroy plants. Control ragweed.
12. Alternaria leaf spot on rudbeckia	Leaf spots and browning of leaves from base of plant upward
Vegetables/ Fruits
13. Green june beetle (southeast Neb.)	Feeding on decaying fruit in gardens and orchards
14. Blossom-end rot	Leathery to soft brown rot on bottom of tomatoes & other fruit
15. Early blight/ Septoria leaf spot	Tomato leaves yellow and brown from bottom of plant upward
16. Fruit sunscald	White, papery or leathery spots on fruits from sunburn
17. Fusarium wilt of tomatoes	Yellowing and drooping of leaves
18. Watermelon anthracnose	Black spots on leaves. Sunken, brown spots on fruit.
19. Tomato bacterial speck/ spot	Raised, black specks or spots; mainly on green fruit
20. Raspberry cane borer	Cane tips wilt and turn black.

 
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
1. White Grub larvae feed on turfgrass roots causing lawn areas to turn brown and sometimes die once grubs damage a large enough percentage of roots. Most white grub eggs have hatched and their numbers should be similar to past years; however, growing conditions conducive to Kentucky bluegrass is likely preventing or delaying damage symptoms. Turfgrass should continue to be inspected for white grubs. If birds are feeding in a lawn, or browning occurs, roll the sod back to look for c-shaped, cream colored, red headed larvae. If eight (8) white grubs are found per square foot, an insecticide application may be justified. At this time of year, Dylox is the insecticide of choice. Do not apply Merit or Meridian at this time of year.

White Grubs, http://www.ianrpubs.unl.edu/sendIt/g1619.pdf

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
2. Chinch Bugs feed on buffalograss and zoysiagrass by sucking juices from leaves and stems and injecting a toxin while feeding which disrupts translocation of water and nutrients. Damage appears as patchy areas which turn yellow, then dry out and turn brown. Damage is usually heaviest in sunny locations during hot, dry periods. Chinch bug nymphs are red with a white band, then orangish, and finally brown to black. Adults are 1/10 th of an inch long and black and white. Control thatch to reduce chinch bugs. If bugs exceed 20 per square foot, insecticide treatment is justified. Products containing Bifenthrin are effective.

Chinch Bugs in Turfgrass, http://ohioline.osu.edu/hyg-fact/2000/2503.html

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
3. Brown Patch causes roughly circular patches of dead and dying grass. Patch centers may be less affected and remain green. Tan colored, irregularly shaped leaf spots with reddish margins are found on leaf blades. Fungicide applications are often not recommended after August 1. Preventive applications of Prostar (commercial use), Bayleton, and chlorothalonil (Daconil) do a fairly good job of suppressing the disease when applied at monthly intervals (June, July, August). Curative applications of chlorothalonil beginning a few days after symptoms of brown patch develop may do an adequate job of suppressing injury. In many cases, lawns damaged by brown patch will recover in two to three weeks, provided the outbreak is not sustained by continuous hot, humid weather; and treatment may not be necessary.

Brown Patch, http://www.oznet.ksu.edu/dp_hfrr/extensn/problems/brnptch.htm

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
4. Rough Bluegrass (Poa trivialis) is a pale green, stolon-forming perennial grass that forms pale green patches in lawns, especially in shady, moist or overwatered areas. It is not heat or drought tolerant and tends to turn brown about mid August. Control nonselectively with glyphosate and reseed the area. Commercial applicators can control selectively in Kentucky bluegrass with a herbicide containing sulfosulfuron (Certainty).

Annual Bluegrass and Rough Bluegrass Control, http://ohioline.osu.edu/srt-fact/0003.html

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
5. Yellow Nutsedge is more abundant this year. Unfortunately, spraying at this time is marginally effective and often results in stimulation of “daughter” tubers attached to the mother plant resulting in a greater infestation of nutsedge. Note where nutsedge hot spots are in the yard; then apply a product containing halosulfuron next year prior to June 21 st, but after nutsedge emerges for the most effective control.

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
6. Two Spotted Spider Mites infest a large variety of plants. Mites and their webs can barely be seen with the naked eye. Mites feed by sucking plant juices with piercing-sucking mouth parts, causing white or yellow speckling 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 miticides or insecticides when mites are active. Tap a branch over a white sheet of paper to monitor for active mites. They’ll appear as specks moving around on the paper if present. Mites can be in the egg stage so monitoring should continue for one to two weeks. NOTE: Carbaryl (Sevin) can increase mites by killing their predators such as lady beetles.

Spider Mites and Their Control, http://ohioline.osu.edu/hyg-fact/2000/2012.html
Spider Mites, http://www.ext.colostate.edu/PUBS/insect/05507.html

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
7. Zimmerman Pine Moth larvae tunnel beneath the bark of pine trees, especially in branch crotches, causing branches to die or break off readily in wind and snow storms. A pinkish mass may be found at the base of infested branches. Insecticides, such as Permethrin, applied during the second week of April and during the second week of August are required for control. Use the label rate for borers and apply to the trunk and major branches.

Zimmerman Pine Moth, http://bugs.osu.edu/~bugdoc/Shetlar/factsheet/christmasstree/zimmerman.htm
Zimmerman Pine Moth, http://www.ext.colostate.edu/PUBS/insect/05591.html

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
8. Cytospora Canker is most common on Spruce trees and commonly causes branches near the base of trees to die or tops of trees to die. Resin often oozes from branch or trunk cankers. There are no fungicide controls. Prune and destroy dead and dying branches during winter. The fungus of often spread during spring rains. Disinfect all pruning tools such as knives and saws by wiping them with rubbing alcohol. Avoid stress by spacing trees correctly, then mulching and watering correctly. Avoid wounds. Black Hills Spruce is less susceptible to this disease.

Diseases of Evergreen Trees, http://www.nfs.unl.edu/documents/foresthealth/diseasesevergreen.pdf

 """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
9. Sphaeropsis Tip Blight of pines can cause entire branches, usually near the tops of trees, to die after a few years of infections by the disease. Most common symptoms are browning and stunting of shoot tips and fungal spores (black specks) on the bottoms of second year cones. Sphaeropsis tip blight can be controlled with fungicides applications made during the third week of April and repeated in 10 – 14 days.

Sphaeropsis Tip Blight of Pines, http://www.ianr.unl.edu/PUBS/plantdisease/g646.htm

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
10. Bagworms have been causing severe damage to evergreens. At this time of year, bagworms are up to 2 inches long and there is only one larva per “brown bag”. Larvae have or are pupating and insecticide applications are not effective once they pupate. Remove and destroy bags to reduce the number of overwintering eggs. Insecticides, such as Bifenthrin, are best applied after eggs hatch in early to mid June.

Bagworms, http://extensionhorticulture.unl.edu/Current/Bagworm.shtml

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
11. Aster Yellows is a common disease that affects many ornamental flowers. Susceptible plants include asters, chrysanthemum, coreopsis, cosmos, Echinacea (coneflowers), dianthus, gladiola, marigold and petunias. Vein clearing, or loss of green pigment within the veins, is often the first symptom. Stunting, stiff extra bushy yellow growth, deformed or poorly developed flowers which remain green are all common symptoms. There is no cure for infected plants. Remove and discard them to reduce further spread. Control ragweed as these plants harbor the pathogen.

Aster Yellows, http://www.oznet.ksu.edu/library/hort2/MF1086.pdf

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
12. Alternaria Leaf Spot on Rudbeckia Fungal leaf spots have been appearing on Rudbeckia (Black-eyed Susans). This, and other leaf spot diseases, cause spots, or lesions, to form on leaves followed by yellowing and browning of foliage, usually near the bottom of the plant first. These diseases do not kill plants. Control with good sanitation and avoid overhead watering.

Rudbeckia Leaf Spots, http://hyg.aces.uiuc.edu/secure/subscribers/200507c.html

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
13. Green June Beetles have been found feeding on fermenting fruit, mainly in southeastern Nebraska. While the larva is a white grub, it is not considered a turfgrass pest. It is unique in that is crawls to the surface at night and moves across the surface on its back. It can also cause soil mounds in the lawn, similar to earthworm castings. Green June beetles are day flyers compared to our brown May or June beetles which are night flyers. Keeping fruit in orchards and gardens picked and not allowing decaying fruit to remain on plants or the ground will keep green June beetles away.

Green June Beetles, http://iaa.umd.edu/umturf/Insects/Green_June_Beetle.html

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
14. Blossom end rot is a common problem of tomatoes, but is also found on peppers, eggplant, squash and watermelon. It occurs as a flat, dry, sunken, brown rot that is seen on the blossom end of the fruit, opposite the stem end. This problem is not an insect or disease. It is a physiological disorder associated with a calcium deficiency in the developing fruit.

Rarely is blossom end rot the result of a lack of calcium in the soil, but rather occurs when plants cannot pull up calcium quickly enough for developing tissues. Calcium is a nutrient that must be dissolved in water to move within a plant, so water deficits are contributing factors. Drought stress, low daytime humidity, high temperatures and rapid, vegetative plant growth caused by excess nitrogen favor blossom end rot development.

To reduce blossom end rot, use these cultural techniques:

1. Prevent drought stress on plants by providing at least 1 inch of water per week, and greater amounts for plants in sandy soils or during very hot, dry conditions.
2. Use organic mulch like wood chips, clean straw, pine straw, peat moss, compost, or herbicide-free grass clippings to conserve soil moisture.
3. Avoid excess fertilization, especially with ammoniacal nitrogen sources.
4. Foliar applications of calcium have little effect on blossom end rot due to poor absorption and movement of calcium from the leaves to fruits.

Blossom-end rot, http://extensionhorticulture.unl.edu/Current/BER.shtml

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
15. Early Blight and Septoria Leaf Spot of tomatoes are the two most common diseases of tomatoes. Both are fungal and begin as leaf spots on lower leaves first and work their way upward causing foliage to die; often leading to fruit sunscald. Use fall s anitation to reduce the amount of inoculum available for infection the following year. In the fall, gardens should be deep-plowed or tilled to bury tomato debris, or dead plants removed and destroyed. Avoid planting tomatoes in the same area year after year. Both diseases can be controlled effectively with fungicides labeled for use on tomatoes. For best results, applications should begin as soon as symptoms first appear, generally around the time of the first blossom set. Applications should be made every 7 to 10 days.  Severely infested plants are best pulled and destroyed.

Early Blight and Septoria Leaf Spotof Tomatoes, http://www.oznet.ksu.edu/hfrr/extensn/problems/earlblht.htm

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
16. Sunscald causes papery or leathery white or tan spots on the surface of fruit exposed to direct sunlight. Sunburn occurs particularly when plants are defoliated by insects or diseases. Control by maintaining healthy foliage that will shade the fruits.

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
17. Fusarium Wilt of Tomatoes begins as yellowing of older leaves. The yellow leaves turn downward and droop. The fungus infects the plant's vascular system, which carries water from roots to leaves. To help confirm Fusarium, cut the lower or main stem and look at the cross section of the stem for a dark brown discoloration. If found, pull and destroy infected plants. There are no fungicides are labeled for control of wilt diseases. Select varieties with resistance to Fusarium (they will have the initials VFN on their label) and use crop rotation. Most tomatoes are labeled VFN, so Fusarium wilt is not common.

Fusarium and Verticillium Wilt, http://ohioline.osu.edu/hyg-fact/3000/3122.html

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
18. Anthracnose on Watermelon causes small, black spots on leaves and leaf yellowing. Sunken spots can appear on watermelons, but may not appear until after harvest. A combination of crop rotation and fungicide applications are necessary for controlling this disease on susceptible varieties. Protective spray applications should be made when vines start to run and should be continued at 7 to 10 day intervals during periods of humid or rainy weather.

Watermelon Anthracnose, http://plantpathology.tamu.edu/Texlab/Vegetables/wmelon/anth.htm

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
19. Bacterial Speck and Spot are two tomato diseases caused by bacteria that may be seed-borne or overwinter on plant debris and on the roots of plants, including weeds. Bacterial speck is favored by cool temperatures, 60-75 degrees F, and high moisture, while bacterial spot is favored by higher temperatures, 75-86 degrees F, and high moisture. Young fruits are most susceptible to infection. Both diseases reduce fruit quality and are easier to prevent than control.

The most noticeable symptoms are raised black spots on fruits. Bacterial spot causes larger fruit lesions, approximately 1/8 inch, while bacterial speck fruit lesions are approximately 1/16 inch. Brown leaf spots often with a yellow halo occur and heavily infected leaves may fall. Blossom blight and abortion may result in poor fruit set.

Manage these diseases with crop rotation, select disease free transplants, remove green tomatoes showing symptoms, clean up plant debris in the fall, and control weeds. Do not handle or work in tomatoes when they’re wet and avoid overhead irrigation.

Bacterial Spot, Speck and Canker of Tomatoes, http://ohioline.osu.edu/hyg-fact/3000/3120.html

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
20. Raspberry Cane Borers damage raspberry plants from early June to late August. Females puncture two rows of holes in raspberry stem tips and lay their eggs between them. The punctures restrict sap flow resulting in wilting, blackening and death of cane tips. Adults are slender, one-half inch long beetles with a bright orange body and two to three black spots. The larvae are white legless grubs found in the interior of the cane. They move down the cane as they feed. Remove and destroy infested stems several inches below the wilted tip as soon as the damage is found.

Raspberry Cane Borer, http://www.ext.colostate.edu/Ptlk/1478.html