Flatheaded Borer

A Wood-boring Beetle

larvae and adult LCThe flatheaded borer is a metallic wood-boring beetle that can do major damage to your trees, even killing young trees. The adult borer lays eggs in crevices or injured areas of trees. The larvae that hatch immediately start to bore tunnels in the wood just under the surface of the bark, which is what they feed on. As the larvae grow they continue to tunnel through the tree, digging deeper and deeper to reach fresh moist wood.

Recognizing an Infestation

Larvae Excavation LCThe borer beetle is identified by its metallic appearance, but their larvae do the most damage. The larvae’s body has a flat enlargement just behind the head, and are light in color. The tunnels made by the flatheaded borer larvae injure the tree and are filled with finely powdered sawdust. Their digging causes sap to flow and the affected area will appear wet. As these wet areas dry they may crack and expose the borers’ tunnels. The tunnels they create are winding and flattened looking with oval shapes at intersections. When the adult beetle emerges from the bark or wood it leaves a characteristic oval shaped hole.Tree Damage LCProtecting Your Tree Asset

insecticideThe best way to protect your trees is to prevent an infestation. By creating a healthy growing environment for your trees, you remove the opportunity for the borer to lay eggs. Proper pruning and care are essential to having and keeping strong, sound trees that can fight infestation.

If you do have an infestation, prune away as much of the infected area as possible and spot treat it by applying insecticide to the surrounding area. Insecticide will only kill the larvae if the chemicals can reach them just below the surface, but it will help to prevent any future invasions. Bayer Tree & Shrub Insect Control is an example of an insecticide that can be purchased at Home Depot to treat a borer infestation.

From the Case Files: Scale Insect

What are Scale Insects?

Scale LCIf you’re noticing small white bumps or film on your cactus, chances are it’s a scale insect. There are roughly 8,000 known species of scale insects. Though scale insects can be found on many species of plants, they are particularly fond of cacti. The most prevalent species of scale insect found in the desert southwest are those in the Diaspididae family, commonly referred to as the “armored scale.” This nickname is derived from the scale-like protective covering the insects hide under. The most common scale insect found in Arizona is the Cochineal Scale.

Scale insects attach themselves to plant tissue and suck the juices from the cactus. Their attachment is surprisingly strong and when they are removed, they typically leave a scar behind. Though a single scale insect will do very little damage to a mature cactus, they multiply rapidly and could potentially cover the surface of an entire cactus in just a few days. It’s easy to recognize the infestation by the frosty, white appearance of your plants.

How to Treat Scale

The first step in treating a scale infestation is to physically remove the scale insects from your cactus. DLC’s experts recommend simply using a hose with a pressured spray nozzle. A high pressure setting can remove the insects with ease. However, you’ll want to be careful to avoid damaging the cactus. When spraying the cactus, be sure to to get down in the cracks and under the spines to ensure all insects are removed. After removing the insects, remain vigilant of any additional signs of scale insects as they sometimes find their way back to your cactus. To prevent repeated infestations, treat your plant with a systemic insecticide. Systemic means the insecticide is absorbed through the plant’s roots, therefore entering the plant tissue and making it poisonous to any scale insect that dare take a bite. For best results, DLC’s experts recommend applying the insecticide once at the beginning of the growing season.

Until the systemic insecticide has taken effect, you’ll want to continue to monitor your cactus and remove any scale insects. Some products we’ve found available at local home improvement stores labeled for scale insect include:

  • Bayer Advanced Tree & Shrub Protect & Feed Dual Action Formula
  • Bayer Advanced Insect, Disease & Mite Control

As always, DLC recommends that you follow the directions provided on the insecticide label prior to application.

Care For Your Ocotillo

Ocotillo_ImageOcotillo, Fouquieria splendens, is a slow-growing plant native to the Southwest region. Boasting tall slender cane stalks that bloom with bright red-orange, trumpet shaped flowers, the Ocotillo is a popular desert landscape plant requiring little maintenance.

Ocotillo Characteristics

  • A mature plant typically reaches 12 feet high and 10 feet wide, but can grow much larger
  • Thrive in full sunlight and attract hummingbirds
  • Deciduous, meaning they shed their leaves through the winter months and leaf out after periods of sufficient soil moisture
  • Can tolerate low temperatures down to 10° F before suffering serious injury or damage
  • Red-orange flowers blossom in the Spring

Planting Your Ocotillo

Soil LineAccording to the University of Arizona’s Cooperative Extension, transplanting is best done March through May. Plant a bare-root Ocotillo in dry, loose, sandy soil with light to moderate amounts of organic content to ensure root development. If your Ocotillo is marked on the South side, it should be planted facing South. To help the ocotillo from falling over or blowing down in a storm, large stones may be placed over the root area (2-4 inches from the trunk). Ocotillos need full sunlight in open areas where surface water does not collect.

Little Maintenance Required

ocotilloThe Ocotillo is highly drought tolerant and considered a low-water-use plant. It will require irrigation after it has been planted. Avoid over watering the soil, as too much groundwater will cause the roots of the plant to rot. Instead, water by spraying the cane of the plant and keep the soil moist. Water newly planted Ocotillos once a day (typically for 10 minutes) and established Ocotillos every month or so.

The Arizona Municipal Water Users Association (AMWUA) recommends the “Do no harm” pruning method. Essentially, the best method of care for your Ocotillos is to only remove dead or diseased wood. This is particularly true for Ocotillos in the ground for less than three years.

Some degree of growth set-back is expected after planting. Wait patiently – these plants often look like they are dead, especially in periods of drought. With minimal care and watering, most Ocotillos will develop into attractive and healthy plants when left alone.

University of Arizona Cooperative Extension Office
AMWUA Landscape Plants for the Arizona Desert Guide

Cactus Care

Cactus LCWatering Guidelines

Cacti have an amazing ability to store water and adapt to new environments. Over-watering combined with poorly drained soil is a recipe for cacti to struggle. The soil should dry almost completely between watering cycles. Check the root zone about 2-3 inches below the surface. If the soil is still damp, wait until it is dry before applying more water. Regularly checking the root zone before watering gives you a good idea of what your plants’ unique watering needs are.

As a general rule, cacti planted in well drained soil can be watered every 10-14 days for one hour (based on using drip irrigation) during the summer months. That amount of time allows the soil to dry thoroughly between watering, yet gives the plant enough supplemental water to survive the heat. As daylight decreases in fall, water should be reduced. As nighttime temperatures drop below 60 degrees, turn off the water completely. Most cacti can survive on natural rainfall alone during winter months.

These watering guidelines apply to most cacti. The one exception is Saguaro cacti. Saguaros should never be watered. If you have a Saguaro that appears to be suffering, consult with your local nursery that specializes in selling cacti.


There is no need to apply fertilizer to cacti planted in the landscape. Cacti planted in pots do occasionally need some fertilizer. In that case, use tomato food (8-20-10) unless you can find specialized cactus fertilizer at a nursery. Apply the fertilizer once a month during the summer months only.

Cacti Challenges

Cacti suffer and often die from three main sources: soil borne pathogens, insects and animals. Pathogens, mostly fungi, affect cacti in many different ways. Normally you will see brown depressions form at the affected area. In some cases, the affected areas can be treated by a fungicide. If the disease has spread to the point where it is highly noticeable, it is better to remove the cactus before the disease spreads to neighboring plants. Proper watering is the key to preventing the spread of soil borne pathogens.

Proper watering also plays a key role in discouraging insects from damaging cacti. Insects are opportunistic and need moisture to survive. Saturating your soil with water is an open invitation to an insect.

Animals, particularly rabbits, find some varieties of cacti tasty and can cause significant damage. The best way to prevent animal damage is to limit access to the plants. Install wire mesh around cacti, especially while they are young. Or simply find a different location to plant your cacti.