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Frequently Asked Questions

GROW GREEN FACT SHEETS are available to download or you can also pick hard copies from many sites around Austin that distribute Grow Green materials.

Other Common Pests and Grow Green Recommendations

The landscape problems listed below occur in Austin but we do not have the same demand for information about them as the pests that have GROW GREEN FACT SHEETS.

Bacterial Leaf Spot

Problem
Leaves yellow and may drop. Plants lose vigor and produce less chlorophyll. Bacterial Leaf Spot is caused by wet plant foliage and injury. This is commonly seen on:

Greens
Turnips
Cauliflower
Cabbage
English Ivy
Tomatoes
Fruit trees
Several ornamental shrubs and trees

Least Toxic Solutions

  • Avoid wetting foliage when watering.
  • Space plants to allow adequate air flow.
  • Do not injure foliage. Bacteria enter plants through wounds or natural openings.
  • Remove infected plant sections.
  • Carefully consider use of chemical controls— they are often only marginally effective.
  • If you must use a chemical control, apply a copper hydroxide product such as Kocide®.

Cotton Rot/Root Rot

Description: Fungal plant disease that attacks the roots of plants, turning them brown rather than a healthy white. Cotton root rot is common in soils with a pH over 7.2 and in areas with high summer temperatures. Problem: Plants wilt, dieback and lose vigor. Control is difficult because symptoms normally appear after damage to the stem or root is severe. Cotton Root Rot moves through the soil from plant to plant, with symptoms usually occurring in July and August.

Attacks: More than 2,000 species of plants including:

Cotton
Ornamentals
Fruit trees
Nut trees
Shade trees
Most landscape plants

Least Toxic Solutions

Cotton Root Rot

No treatment available once plant is infected. Mulch plants to keep soil cool. Add organic material to clay soils. Use resistant plants, natives and grasses. When practical, acidify soil in the root zone of the plant.

Root Rot

Ensure proper drainage and allow excessively wet soils to dry. Plant in raised beds if drainage is marginal. Avoid crowding plants in beds. Place plants at the same soil depth as they were in the container you purchased them in. Because there are several different fungi that cause root rots, have the disease diagnosed at the Texas A & M Plant Disease Lab or by Extension personnel before applying fungicide.

Fire Blight

Description: Bacterial disease that causes rapid blackening and desiccation of blooms and foliage. Affected shoots bend at the tip in a "shepherd's hook". Black, sunken twig and branch cankers develop later. Problem: Fire Blight causes twig dieback and blossom blight in up to 2-24 inches of twig length. The bacterium stays in the cankers over winter and in the spring, oozes from the cankers and is carried by wind, rain and insects to healthy foliage.

Attacks:
Pears
Apples
Pyracantha
Quince
Loquat
Indian Hawthorne
Photinia

Least Toxic Solutions

Avoid high nitrogen levels and excessive pruning. Vigorous growth is much more susceptible to fire blight. Prune four inches below visible cankers. pruning equipment between cuts with one part household bleach to nine parts of water. Clean and oil equipment after pruning. Select fire blight resistant varieties and species. Contact the Extension office at 854-9600 for a list. With the exception of Kocide® and streptomycin sulfate, chemical controls are usually ineffective.

Oak Wilt

Description
Fungus that plug water-conducting vessels, reducing flow of water up the stem of the tree. Often causes leaves to wilt and fall prematurely. Live Oaks: Tree appears weakened. One area of the tree dies at a time. Areas around leaf veins are often brightly colored.

Red Oaks: Die in a flash of fall color in early summer.

Problem
Disease spread by beetles feeding on tree wounds. Also can travel from tree to tree through interconnected roots. Oak Wilt travels 75 feet per year in all directions. Live Oaks die quickly one tree at a time.

Attacks

  • Blackjack Oak
  • Live Oaks
  • Schumard Oak
  • Spanish Oak/Texas Red Oak

Least Toxic Solutions:

  • Prune oak trees only in the coldest part of winter and hottest part of summer.
  • Use a pruning paint to protect cut or wounded areas immediately after pruning or wounds are discovered. Sterilize tools after pruning.
  • Contact Chris Dolan, City of Austin Oak Wilt Suppression Program at 512-974-1881 for information.
  • Trench 4' deep and at least 100 feet from infected and susceptible trees to sever root connections.
  • Only use old, dry wood if you use oak firewood.
  • Certified applicators can inject ALAMO® into tree roots. This method is best used as a preventative.

Thrips

Description
Description To the naked eye, they look like tiny threads; with a hand lens, their narrow, fringed wings are visible. When holding an infested rose bloom you can see that they are very active. They may even bite!

Infestation
Tattered flowers, deformed flowers, silvery spots or streaks on leaves - by the time damage is visible the infestation is already severe.

Attacks:

  • Roses
  • Daylilies
  • Iris
  • other flowers

Lifecycle
Adults lay hundreds of eggs in plant tissue. In Roses, the eggs hatch inside the flower bud. The resulting nymphs scrap plant tissue, then, suck the sap, damaging the flower before it opens. There are many generations per year.

Least Toxic Solutions: Thrips are notoriously very difficult to control, so early detection is important when trying to keep the populations in check.

Aim for control rather than eradication. The only way to completely get rid of thrips is to destroy the infested plants - not an option most want to consider

  • Remove and dispose of infested blooms
  • Clean up leaf litter
  • Always read and follow pesticide labels
  • Alternate the following treatments:
    • Spray with Neem oil. For best results the spray needs to come in contact with the insect, but Neem oil is also slightly systemic; meaning some of it will absorb into the plant tissue and help weaken the insect after it feeds on the plant
    • Dust plants and immediate area with diatomaceous earth Use a light weight horticultural oil

Viruses

Description
Sub-microscopic infectious particles that multiply only inside living cells. Viruses enter plants through wounds and by insects that feed on plants. Symptoms vary but include abnormal color, vein patterns, shape, mottling, ring spots and mosaic patterns in leaves; Can include abnormal flower color and fruit size, shape and color.

Problem
Seldom lethal to plants, but severely affect the quantity, quality and longevity of the host plant.

Attacks
Many types of plants.

Least Toxic Solutions:

  • Chemicals do not effectively control virus diseases.
  • Select plant stock that is free of viruses.
  • Cover susceptible annual garden plants with a row cover fabric to keep sucking insects away from healthy plants.
  • Diseased plants should be removed and destroyed to prevent infection of other plants by sucking insects that move from plant to plant.

Additional Links

Learn more earth-wise gardening tips at www.GrowGreen.org

In 1990, the City authorized this program to review and regulate City pest control activities.

The IPM program has the following responsibilities:

Developers
If an IPM plan is required, developers should be informed during the development review process. It is then their responsibility to submit, and comply with, a plan. If the land is then sold, it is their responsibility to communicate the need for the new land owner to abide by the plan.

Submit an IPM Plan

Homeowners
If you own an individual parcel of land that requires a site plan review and no developer or previous owner has submitted an IPM plan, then it is your responsibility to do so.

 

If you purchase a property that already has a plan, then it is your responsibility to abide by the plan.

The Save Our Springs Ordinance (SOS) was adopted in 1992 and differed from its predecessors because it became law by citizen initiative. Two ordinances worth noting preceded the SOS Ordinance: the Interim and Composite Ordinances. These ordinances addressed development in the Barton Springs Zone, which includes Barton Creek and the other creeks draining to, or crossing, the Edwards Aquifer recharge zone. Highlights of these ordinances included: the first requirements for non-degradation (based on stormwater discharge concentrations) and provisions that excluded variances unless a demonstrable improvement in water quality was shown. Variances, which made departures from an ordinance permissible, were a general feature of watershed ordinances up until this time.

The SOS Ordinance, applied throughout the Barton Springs Zone, required: non- degradation (based on total average annual loading), and lowered impervious cover to 15 percent NSA for all development in the recharge zone, 20 percent NSA for development in the Barton Creek portion of the contributing zone and 25 percent NSA for development in the remaining portions of the contributing zone in Williamson, Slaughter, Bear, Little Bear and Onion Creeks.

 

IPM Plans for Water Quality Protection are required when one or more of the following conditions exist:

Regulatory

  1. When land is developed in the Barton Springs Zone (required since 1992 under the Save Our Springs, SOS, Ordinance); homes and businesses built before the ordinance are grandfathered and do not require IPM plans although voluntary compliance is encouraged
  2. When a City Board or the City Council requires an IPM plan (usually occurs when a developer request a variance from regulations)
  3. When the requirement is written into an agreement, such as for a PUD or to qualify for Green Building certification credits
  4. Per the Environmental Criteria Manual (ECM), when specific water quality treatment systems are used on commercial properties, including:
    • Wet ponds (1.6.6)
    • Retention/Irrigation (1.6.7.A)
    • Vegetative filter strips (1.6.7.B)
    • Biofiltration (1.6.7.C)
    • Rainwater harvesting (1.6.7.D) if used in conjunction with vegetation
    • Disconnection of Impervious Cover to Vegetated Filter Strip (1.6.7.F)
    • Non-required vegetation (1.6.7.G)
    • Rain gardens (1.6.7.H)
  5. On intensive landscape management sites such as athletic fields and golf courses. These require customized IPM plans because the anticipated pests are more likely to be specialized

Developers

If an IPM plan is required, developers should be informed during the development review process. It is then their responsibility to submit, and comply with, a plan. If the land is then sold, it is their responsibility to communicate the need for the new land owner to abide by the plan.

Homeowners

If you own an individual parcel of land that requires a site plan review and no developer or previous owner has submitted an IPM plan, then it is your responsibility to do so. If you purchase a property that already has a plan, then it is your responsibility to abide by the plan.

Submit an IPM Plan