Tag insect activity

The recent explosion of aphid activity in North Texas caused frustration and concern among tree owners and anyone who has encountered the sticky mess that aphids cause. When aphids have matured and are feeding (and producing honeydew), best practice guidelines do not recommend using chemical controls. Introducing natural aphid predators can help reduce the population, but the best course of action, especially with a fall aphid infestation, is simply to wait about a month for the aphids to die off and cooler weather to prevent another generation from maturing.

Are There Any Natural Ways to Get Rid of Aphids?

Chemical pesticides are not the only way to control aphids. One of the most effective and long-lasting ways of reducing aphid activity is to introduce natural predators of the aphid into the environment. With an autumn infestation, however, there is limited time to act and leaves may drop and temperatures fall before any aphid control has a chance to make a difference.

While lady beetles are a welcome addition to the garden, some non-native species can invade our homes during winter. These lady beetles often have an “M” or “W” mark on their shells, just behind the head. To keep your home lady beetle-free:

• Keep trees and bushes trimmed back from structures
• Avoid stacking firewood next to the house
• Seal up cracks around windows
• Use wire mesh to screen large vents

Taking a few precautions will not only keep lady beetles out of your house, but block larger and harmful pests as well!

Lacewings

• Two major varieties: green lacewings and brown lacewings, in order Neuroptera
  • Lay distinctive single eggs on stalks
• Larvae often called “aphid lions”
  • Can consume up to 200 aphids a week
  • Adults can feed on aphids as well
• Take about two to three weeks to hatch and mature from eggs

There are species of lady beetle and lacewing that are active in the spring and in the fall, so there is a potential for year-round aphid control. Introducing lady beetle larvae can have a serious effect on aphid activity, but keep in mind that, depending on the species, the predators may not survive winter and may need to be re-introduced in the spring.

In addition to predators, simple physical controls, such as using water to remove aphids from plants, can also help in the short term. Avoid using high-nitrogen fertilizers as these can stimulate rapid growth and attract more aphids. Luckily, with fall aphids, once the leaves drop and their food source is removed, the pests will die off quickly.

Why aren’t Chemical Controls Effective for Fall Aphids?

There are several chemical insecticides that target aphids. These products generally break down into two categories: systemic and non-systemic.

• Systemic Pesticides
  • Absorbed into the the plant they are applied to and transported throughout the plant’s structure
    • Can take up to a month for chemical to become present throughout mature trees and reach full effectiveness
  • Generally effective for longer than non-systemic
    • Resistant to being diluted or washed away by rain
  • While present in plant, can protect both new and old growth
  • Can be applied before growing season or anticipated increase in pest activity
• Non-Systemic Pesticides
  • Cling to the surface of treated plants
    • Effective immediately
  • At risk of dilution or removal by rain, sprinklers, etc.
  • May not protect growth after application
  • Can be applied preventatively, but timing more important due to risk of dilution/loss
  • Difficult or impossible to apply to large trees/plants
    • Large-scale spraying may lead to environmental contamination

Comprehensive pest management often uses both systemic and non-systemic chemicals to provide maximum protection. Before a growing season, in late winter for example, it is common to apply a surface spray and a systemic insecticide to crape myrtles and other trees that are susceptible to insect infestations in the spring. The surface spray provides protection while the systemic product has time to come to full effectiveness.

In the case of insect activity in fall, chemical controls should not be applied as they would be before a growing season. Non-systemic pesticide sprays can be effective against current pest activity, but in the case of large, mature trees, such as the pecans and oaks infested with aphids in the fall of 2022, applying sufficient quantities of external pest control is not only expensive, but is potentially hazardous to the surrounding environment with the high potential for overspray and excess application. Furthermore, as fall in North Texas often brings rain, any product applied may be washed away quickly, and possibly end up in the groundwater.

Systemic insecticides carry a much lower risk of environmental contamination, but take about a month to become effective. In the case of a fall application, systemic controls may take even longer, as trees begin going dormant and dropping leaves, slowing the uptake of both nutrients and chemicals. In general, it is not recommended to use any systemic insecticides in the fall, as the likelihood of their becoming effective before the pests naturally die off is low.

In summary, be wary of service providers who claim that they can control fall aphids chemically; they may be able to reduce activity, but full eradication is nearly impossible and runs a high risk of contamination and waste of chemicals, time, and money.

At Texas Tree Surgeons, we love trees and we love our community! These fall aphids have been a real nuisance, and we want to give our customers the best advice so that money and time is not wasted on ineffective treatments. While we don’t recommend chemical application for fall aphids, we are big fans of introducing some aphid predators while you still have time! As a woman-owned and women-led company, we are partial to lady beetles :-), but lacewings are great, too! Share this article and spread the word about aphids, and let us know if you have any other tree questions!

We have discussed the relationship between aphids and the sticky residue seen on patios and cars before, but the Fall of 2022 has seen an explosion in aphid populations and the resulting mess. While there is little that can be done to reduce aphid activity this season, it is unlikely that the aphid infestations will have a lasting negative effect on trees in North Texas.

Why Is My Tree Dripping Sticky Stuff? Is It Sap?

While it may be confused with sap, the sticky substance we are seeing dripping from trees is most likely honeydew, which is produced by aphids. Aphids are attracted to many different species of tree, but are most commonly seen in North Texas on crape myrtles, pecans, hackberries, and certain oaks.

• The aphids feed on sap and produce honeydew, which accumulates on the trees, eventually dropping.
  • Since honeydew is essentially sugar water, it can cause surfaces it comes in contact with to become sticky.
  • The sugary residue can also attract ants and other animals.
  • In large enough accumulations, honeydew can lead to the growth of molds and fungi, such as sooty mold, which is commonly seen on aphid-infested crape myrtles.

Why Is This Happening Now?

Like the trees they prey on, aphids are greatly affected by seasonal weather patterns and changes to their environment. In 2022, we had a long, dry summer that ended with heavy rainfall. The abundance of moisture at the end of the season combined with still-elevated temperatures caused rapid growth of many plants, blooming of flowering trees and bushes, and a resurgence in the insect population. The abundance of new growth late in the year was able to support many more species that feed on plants, like aphids, than the previous year’s late summer. While this is not the first time this has happened in North Texas (see our post about this same topic from October 2018), it happens rarely enough that it can be surprising when it occurs.

Is There a Spray or Other Treatment for Aphids?

• Foliar sprays to control insects are not recommended for large trees (such as pecans and oaks), and have a very limited window of effectiveness.
  • Additionally, any product that is applied to a tree rather than used systemically is subject to being diluted or washed away entirely by rain.
• Systemic insecticides can be used in trees of all sizes, but take about a month from application to be taken up by the tree’s vascular tissue and reach full effectiveness.
  • Because of this timing, systemic insecticides are best applied before a growing season or an expected surge in insect activity.
• Be wary of service providers who claim to be able to control an active aphid infestation quickly.
  • They will either not be able to deliver on that promise, or will use a wasteful, excessive, and potentially dangerous insecticide spray that could be rendered ineffective in the next rainstorm.
• Effective treatment takes time, and if the aphids are already active, they will most likely die off naturally before any chemical controls could make a difference.

What Can We Do About the Current Activity and Sticky Mess?

• Depending on the size of the host tree and the number of aphids present, it may be possible to spray some of them off the tree with a garden hose.
  • Ladybird beetles (laybugs) and some other insects are natural predators of the aphids, but trying to introduce them into the environment late in the season may not be effective.
• The sticky honeydew is water-soluble and easily cleaned up with a mild detergent solution or a mixture of vinegar and water.
  • If possible, avoid parking under infested trees and cover patio furniture until the activity dies down.
• Once their life cycle has run its course, the aphids will die off naturally.
  • With a lifespan of between 20 and 40 days, by the time the current generation of aphids dies, the weather will have cooled enough to prevent further activity until the next growing season.
• To help prevent future infestations, and stop current ones from getting worse, avoid using high-nitrogen fertilizer that stimulates rapid plant growth, as this will only serve to make your trees more attractive to pests like aphids.

Will the Aphids Cause Long-Term Issues in My Trees?

While an active aphid infestation can cause irritating honeydew production and unsightly mold growth, there are most likely no lasting effects on large trees. Increased insect activity late in a season is less likely to cause long-term damage. Additionally, even large populations of aphids rarely have any serious effect on mature trees. Once the aphids die off, any secondary issues, such as mold, will clear up.

At Texas Tree Surgeons, we love trees and we love our community! We hope that spreading the word about the current aphid issue will help put tree owners’ minds at ease. While nothing can be done to reduce aphid activity right now, there are preventative measures that can be taken in the winter to help reduce pests in the spring. We offer year-round plant health care programs that can help make sure your trees are prepared to handle issues at any time and bounce back from damage and stress. Ask one of our certified arborists to evaluate your trees today!

Another installment in our series of posts where Texas Tree Surgeons answers your tree questions. Are you having problems with your trees and want to know what’s wrong? Let us know!

My cedar tree has bagworms. Can you treat for that?

Bagworms are a common pest in North Texas, especially on cedars, junipers, cypresses, and other evergreens, although they can attack broad-leaf trees (like oaks, maples, and elms) as well. While they are common, they may not always be noticeable, especially on evergreens, as they use material from the trees they infest to camouflage their casings. Like other insects, bagworms have a year-long life cycle, and control measures depend on the growth stage of the pest.

What Are Bagworms?

• Bagworm is the common name for several different species of insect which are actually a type of moth (order Lepidoptera, family Psychidae).
• The bagworm caterpillars are very small (about 1/25 of an inch long), and spin silk thread which they use to attach themselves to plants and to weave into their bags.
  • Unlike a typical cocoon, the bagworm’s casing functions as a moveable shelter, with the caterpillars exiting to find food and climb up the plant.
• Once the caterpillar has matured, it undergoes a metamorphosis period before emerging as an adult.
  • Male bagworms resemble small moths while the females are flightless.
• Male bagworm moths seek out females during mating season, and the female uses her bag to lay eggs.
  • The exact times of caterpillar and adult emergence varies from species to species and is dependent upon the weather.

Can You Treat For Bagworms?

While bagworms are not prevalent every year, once they have infested a tree, they will continue to live there unless controlled.

• The simplest control method is to remove the bags.
  • They can be pulled off by hand or sprayed off with high-powered water.
  • It it important to dispose of the bags or destroy them, and not just leave them lying on the ground, as the eggs they contain can hatch and re-infest the tree.
• Insecticide sprays can be used to control bagworms, but are most effective when the caterpillars are small, and can be completely ineffective if the bagworms close their bags, as they do to molt or over the winter.
  • Systemic insecticides may be used in some cases as a preventative measure. Consult a certified arborist to see if this may be a good option for you.

At Texas Tree Surgeons, we love trees and we love our customers! Bagworms are a widespread nuisance and, while one or two may not harm a mature tree, can cause large-scale defoliation if left unchecked. It is a good idea to remove any bags that you see, whenever you see them. If you have bagworms, and want to see if there might be a chemical treatment option, contact us to set up a visit from a certified arborist. We offer full-service plant health care, including fertilization to help trees stressed by bagworms recover. We look forward to hearing from you!

Another installment in our series of posts where Texas Tree Surgeons answers your tree questions. Are you having problems with your trees and want to know what’s wrong? Let us know!

As we move into summer, there are several tree health issues that can present themselves. One of the common questions we get around this time is about bumps on pecan leaves. The bumps are the result of insect activity that may or may not affect the pecan fruits themselves. Unfortunately, once the bumps appear, there is no effective control for the pests. Still, knowing what is afflicting the tree means you can make preparations for treatment next year.

Pecan Phylloxera

The insect that causes the bumps to appear on pecan leaves is called pecan phylloxera (Phylloxera devastatrix). Pecan phylloxera is a small, aphid-like insect that feeds on the shoots, leaves, and buds of the pecan tree. There are two main types of pecan phylloxera: one that affects leaves only, and one that affects leaves and nuts. The leaf phylloxera can cause defoliation but generally do no greater harm to the tree. The other kind, however, can cause severe leaf drop and inedible fruits. As both kinds of phylloxera cause leaf bumps, called “galls,” it can be hard to tell which one is affecting your pecans. However, if you have a lot of leaves falling, there is a good chance that it is the more invasive phylloxera.

No matter what particular kind of pecan phylloxera is present, the insects follow a similar life cycle. In the summer, eggs are laid in the bark of the pecan tree. The eggs hatch in the spring and the young insects move to the shoots and buds, where they begin to feed, forming galls on the new leaves for protection. Once the phylloxera have matured, they emerge from the galls to mate and lay eggs for the next year.

Treatment for Pecan Phylloxera

Because of their life cycle, the only effective time to treat for pecan phylloxera is in the spring, just as the leaves are budding. Applying insecticide at bud break can prevent the phylloxera from becoming established in the new leaves. Once the galls have formed, the insects are protected from pesticides, and cannot be effectively treated.

Pecan phylloxera moves slowly and may not affect every tree in an area every year. Variations in weather and tree growth can greatly affect the ability of the insects to survive. Still, if you have bumps on your pecan leaves, it is best to plan for insecticidal treatment for pecan phylloxera the following spring.

At Texas Tree Surgeons, we love trees and we love our customers! We know it can be frustrating to find out about a problem too late to do anything about it. Hopefully, learning about pecan phylloxera now will help you be prepared for treatment in the spring. If you have questions about bumps on your pecan leaves, let us know, and a certified arborist can confirm what is affecting your tree and what you can do about it!

Another installment in our series of posts where Texas Tree Surgeons answers your tree questions. Are you having problems with your trees and want to know what’s wrong? Let us know!

Dear Texas Tree Surgeons,

I’ve been hearing about the emerald ash borer, and it seems pretty serious; should I be worried?

-J.G.

You may have seen recent media coverage of the discovery of the emerald ash borer (“EAB”) in Texas. The emerald ash borer (Agrilus planipennis) is a small, green beetle that feeds on ash trees. Though native to Asia, EAB first appeared in North America in 2002. In 2016, EAB was found in northeast Texas. In July 2017, suspected EAB specimens were found in Tarrant County. In early December 2018, the Texas A&M Forest Service confirmed that several ash trees near Eagle Mountain Lake had been killed by EAB infestation. In May 2020, Texas A&M confirmed presence of EAB in the Denton area.

Should I be Concerned About Emerald Ash Borer?

The threat from EAB is a serious one, as ash trees make up between 5-13% of the DFW urban forest, and are important providers of shade and clean air. If you do have ash trees, however, EAB infestation can be prevented.

Emerald Ash Borer Prevention Tips

• If there are diseased or damaged ash trees, consider removal before they have a chance to be infested.
• If there is EAB activity within a few miles, consider preventative systemic insecticide treatment.
• Keep an eye out for signs of EAB activity:
  • Dead/dying branches in upper crown
  • Shoots/suckers along trunk
  • Splitting bark with insect trails underneath
  • Increased woodpecker activity
  • D-shaped exit holes

Can Emerald Ash Borer be Treated?

Unfortunately, once an ash tree has been infested by EAB, there is little that can be done. Insecticide treatments can help slow the decline of the tree, but once more than 50% of the canopy is gone, treatments are not effective. EAB generally kills infested trees in two to five years.

So, yes, the emerald ash borer is a serious threat to ash trees, but education and awareness now can help mitigate its effects. If you have ash trees, take note of their appearance, and contact your arborist if you see any signs of decline. If you don’t have any ash trees, you do not need to worry about EAB at all.

For more information on EAB, visit the Texas A&M Forest Service. For help identifying your trees, visit Trees of Texas.

At Texas Tree Surgeons, we love trees and we love our community! The spread of emerald ash borer, while a threat to a small percentage of North Texas trees, is a threat that we can all help to fight against. If you have ash trees or know someone who does, let us know, and one of our ISA Certified Arborists will be happy to evaluate the trees for EAB risk factors and provide options to keep them safe and healthy.