Feeding Damage on Agave sp.

The feeding damage on the agave leaf shown in the photo is the latest of several similar examples that have come into the Cooperative Extension office here in Casa Grande, Arizona, USA.  The leaf shows hollowed out sections on the inner surfaces and missing sections at the leaf's margins.

The temptation, of course, is to blame an insect for the damage, but there are no known insects that would cause this kind of damage to agave species here in the Sonoran desert.  The agave snout weevil larva is a known pest on agave here but it is an internal feeder and causes an entirely different set of problems.  Typical agave snout weevil damage causes the drying and collapse of the entire plant.

The damage shown here is probably caused by a small mammal, such as a ground squirrel or more likely a small plant feeding rodent.  While we have not been able to positively identify the animal causing the damage through direct observation, we are fairly sure that we are on the right track.

Plants showing this kind of damage are typically younger and smaller plants, so it may be that as a plant ages and matures, the leaves become less attractive.  If we can get some growth on the plants, we should obtain relief from the feeding.

One way to protect the plant from further damage is to build a frame over the plant and drape the frame with bird netting.  Wire fencing is sometimes recommended to protect plants from vertebrate damages, and it works particularly well with rabbits, but fencing seems to be less effective against smaller animals because they tend to climb over the barrier.  Bird netting appears to work better, perhaps because they fear becoming entangled in the clingy mesh. As the plant matures, the netting can be removed.

If you would like to discuss this further, call one of our Master Gardener volunteers at 520.836.5221 extension 204. 

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Ten Signs That A Tree Is Planted In the Wrong Place

Planting a tree in a location where it will fail to thrive, or where it will become a nuisance, can be a costly mistake.

Trees, shrubs and bedding plants provide many benefits to a residential landscape, including beauty, shade and a welcoming feel to outdoor living areas.  A handsome, functional landscape also adds value to the home and can put extra money in the pocket when the home is sold later on.  In order to maximize these benefits, it is important to properly plan, install and care for the landscape.

Unfortunately, far too many mistakes are made at planting.  In horticultural terms, it is a mistake to plant a tree where soil or environmental conditions will not favor good growth, where it will eventually need regular and heavy corrective pruning or where it may need to be completely removed within a few years.

Heavy corrective pruning destroys the natural form and beauty of the tree and opens it up to possible infection by plant disease organisms and insect pests.  Removing and replacing a tree results in the loss of the plant’s immediate value.  It also means a loss of the valuable time required to bring the tree to maturity.  By taking the time to do the project right the first time, the owner or manager of a valuable landscape can save both time and money.

Here are ten common signs that a tree has been planted in the wrong place.  If you are getting ready to install a landscape, a good first step would be to take a drive or walk into any residential or commercial area and learn to recognize these mistakes. Then, as you plan your landscape, make sure that they do not show up in your yard.

Sign number one: the tree is growing into a power line.  Tree limbs growing into electrical lines strung from power poles can be dangerous hazards to people and property.  Maintenance crews regularly trim out branches that grow into and around these lines.  Trees that have been trimmed for safety often have their natural form, and their value, either seriously damaged or destroyed.  Many times these trees end up being removed completely.  When siting a tree, place it in a location where it will can grow in its natural form without danger of growing into power lines.

Sign number two: the tree branches grow into the street.  Planting a tree too close to the street will cause the tree eventually to spread its branches into a place where bicycle, car, and truck traffic will either hit, or swerve around, the branches.  In either case, the tree becomes a safety hazard that will need to be severely pruned or removed.

Sign number three: the tree limbs and branches grow over the fence into the neighbor’s yard.  If the neighbor doesn’t mind the tree or the shade that the tree provides, this may not be a problem.  More frequently than not, however, the people next door would prefer that a tree not invade their space.  The hassles, problems and potential conflicts that could occur are easily avoided  by planting the tree in a location where it will not cross property boundaries.

Sign number four: the tree branches rub on the exterior walls or the roof of the house.  Branches blowing too and fro in the wind can scrape and damage brick, paneled, or stucco walls.  They can also rip asphalt shingles or break tiles on the roof.  Plant the tree away from the home to avoid expensive repairs.

Sign number five: the trees grow into each other.  Trees planted too close together compete for water, air, nutrients and sunlight.  A lack of proper nutrition or sunlight will often stunt plants and weaken their trunks and branches. Branches that cross and rub against each other can easily be damaged and ruined.

Sign number six: the tree is damaging water, sewer, or natural gas lines.  Some trees have aggressive, fast-growing roots that can overpower and damage underground utility lines.  Sewer pipes are particularly vulnerable, for example, to the invasion of mulberry tree roots.  Depending upon the type of line, the damage can range from a mere frustration to one of real danger.  It is important to know where the lines are on the property, and avoid them.

Sign number seven: the trees shade out lawns and flower beds and make them unproductive.   Dense shade from large trees will often prevent lawn grasses, bedding plants, shrubs, vines and other trees from properly growing as they shade out their smaller competitors. 

Sign number eight: the tree is in a place where it can heave and buckle sidewalks and fences.  The roots of large trees, if they grow too close to the surface of the soil, can push up sidewalks and fences.  This type of structural damage can be difficult, as well as expensive, to repair.

Sign number nine: a caliche layer or structural hard spot in the soil causes the roots of trees to grow up close to the surface of the soil.  Shallow, improperly rooted trees can more easily blow over in a windstorm.  This problem can be avoided by checking the percolation of water through the soil prior to planting and by properly preparing the planting hole.

Sign number ten: the tree cannot be properly irrigated in a timely manner because water on the property is unavailable or is too expensive for the budget of the person paying the water bill.  Trees will become seriously damaged, or even die, if they do not receive the proper amount of water during the growing season.

Planting a tree in the wrong location is one of the more obvious and expensive mistakes that is all too commonly made during landscape planning and installation.  By taking the time to plan and install trees properly, major landscape mistakes can be avoided.  This will result in savings of both time and money.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, extension 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Mending Drip Irrigation Tubes

Ever cut through a drip irrigation line?  I have and it is not a good feeling.

There are few disconcerting, even sickening, feelings than to be shoveling merrily away in the garden and suddenly feel that distinctive “crunch” when you cut through a drip irrigation line.  When this happens you have three choices: 1) give up on gardening completely, walk away from the site of destruction, and find another hobby; 2) call someone to come fix the line, or 3) get out the tools and supplies and repair the damage.  Most of us, after having gone through the “Oh, no!  What have I just done!” stage, select number three and get it done.

Even if you are one of the lucky ones and have never sliced through a drip line, it is still a good idea to regularly make sure that all is working properly and, if not, conduct regular maintenance.  Because plants depend upon the irrigation system for life-giving water, the overall success and health of our plants is dependent upon how well the system functions.  Good maintenance is a key to garden and landscape success. Finding plugged emitters, broken lines, or clogged filters during the heat of summer is no fun, and regular maintenance during cooler weather will often prevent these mid-summer hassles.  Still, accidents happen and damage occurs.  With plastic drip irrigation systems, repairs are usually fairly simple. 

First, locate the exact site of the problem. If the tubes are underground, a sure fire test for cuts or tears in the delivery system is to look for water soaked areas on the surface of the soil.  Water escaping from a line under pressure will soak through to the soil surface and create a boggy area that is much more moist than other areas around it.  Excavate the irrigation line by digging carefully down to the tube and search for a cut or slice.  If you have an above ground system, look for geysers spraying into the air.

Once you have found the exact site, you next have to decide how best to repair it.  For simple slices or nicks, couplers are the best way to go.  To save time traveling back and forth to the store for the correct parts, it is a good idea to plan the repair job first and then assemble a parts list.  This is also the time to decide on what tools you will need.  Hunt them all up and have them ready to hand before starting the project. 

The biggest challenge to quick and easy repairs is to have the correct-sized parts on hand.  It does no good to have a three-eighths coupler to fit a half-inch line.  It just won’t work.  However, most drip tubing is of a uniform size which makes it easy to find the right parts.  It is always a good idea to double check everything before getting down on elbows and knees in the mud to do the actual repairs.

Once you have all the parts together, it is time to start the job.  At the point where the damage has occurred, use a sharp knife or small hand saw to make a straight up and down cut through the tubing.  This will make sure that all of the fittings will match evenly and seal tightly.  A cut that is uneven will leave a side with less plastic to plastic contact resulting in locations where leaks may occur.

Just about any plastic tubing can be easily repaired with slide on, or in, couplings that join the two ends of the tube in a water-tight fitting.  These couplings are available at any hardware or garden store that services drip irrigation systems. 

The barb coupling has concentric ridges on the outside and around each end of the coupling.  The barb coupling slides into the plastic tubing as far as the coupling will allow.  The barbs grasp the inside of the tube to provide the necessary tight fit.

A compression coupler is different in that it slides over the top of the plastic tubing.  Both compression and barb couplers take a little work to move them into the right position for a strong, water-tight fit.

Those who are experienced in making repairs generally agree that the compression coupler is the better way to go.  Even though they are almost double in cost over the inside-the-tube barb couplers, they seem to have a better track record of success.  This is probably due to the water pressure inside the tube.  As pressure builds, the tube expands or swells in diameter slightly.  For compression couplers, the increased pressure pushes the tube  even tighter against the coupler, and thus, creates a tighter fit.  On the other hand, the pressure tends to loosen the connection between the inside-the-tube barb couplers.

If the damage is in thicker-walled PVC pipe, slide-on PVC couplers will work for small breaks, but extensive damage may require the replacement of sections of pipe.  Remember that PVC must be glued together with an approved adhesive.

Damage to above-ground feeder lines or emitters are fairly easy to repair.  Most systems are designed to add or remove emitters easily.  Holes created for emitters or spaghetti tubing can be plugged by snapping in “goof plugs,” attachments that are designed to correct mistakes in the assembly process.

Sometimes drip system filters will become plugged with precipitated salts, algae, or sand.  Most filters can be removed and rinsed to ensure good service.  If the screen inside the filter is damaged, replace it. The filter is a critical part of the system and scrimping and “making do” can cause you many headaches down the road.

All drip irrigation systems need to be flushed out regularly to get rid of accumulated contaminants that might collect at the end of the tube.  At the end of each line, there should be an access point which can be opened to allow the water to flow freely.  Once opened, the water pressure should push out any contaminants that might be inside.

With a little know-how and some time, your labor-saving system can be back up and running just like new, that is, until you cut it again.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, extensioin 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Minimizing a Heat Island Effect

We live in the Sonoran Desert.  Because of that we are accustomed to hot summer temperatures.  Have you ever noticed that the temperatures in Phoenix always seem to be several degrees higher than in the smaller communities around?  This is often referred to as the heat island effect.

The heat island effect is a natural phenomenon that causes daytime temperatures within cities to increase by up to 6 degrees F. over temperatures in rural areas at the same time of the day.  Nighttime temperature differences can be as much as 9 degrees.

Are you finding yourself a little skeptical?  Let’s look at an example.  If the daytime temperature in rural areas hits 106 degrees, which we would say is a pretty nice day for late June and July, the addition of another 6 degrees turns a tolerable day into a 112 degree scorcher.  If the rural temperatures are higher, as we know that they will be, ... well, you can do the math.

Heat islands are caused, pure and simple, by urbanized development and growth.  Roads, buildings and other hard surfaces, especially dark-colored surfaces, absorb and retain heat.  Surface temperatures fifty to seventy degrees hotter than normal soil surfaces are not uncommon.  It is the accumulation of this heat, and its subsequent release back into the atmosphere, that leads to higher ambient temperatures in urban areas.

In a 2002 article in the scientific journal Urban Ecosystems, 6: 183-203 named “Urbanization and Warming of Phoenix (Arizona, USA): Impacts, Feedbacks and Mitigation”, the authors found that at Sky Harbor Airport, urbanization has increased the nighttime minimum temperature by 5 degrees C., or 9 degrees F., and the average daily temperatures by 3.1 degrees C, or 5.6 degrees F.  Additional studies have recorded temperature increases in other cities.

High temperatures affect us in many ways.  In addition to simple heat stress to you and I, other effects, proven or implied, include increased crime rates, higher cooling bills during the summer, additional stress on landscape plants and higher insect pest activity. 

Crime rate increases in warmer weather versus cooler weather have been seen and documented in many places.  A mathematical formula has even been developed.  Plugging in the 3.1 degree C. increase in Phoenix into this formula tells us that the higher temperatures could mean an increase of an additional 25 violent crimes per 100,000 annually.  There is some controversy over whether there is a downturn in the temperature-crime relationship at very high temperatures, so this effect needs more study.  

Higher temperatures bring on a greater need for power to cool our homes, businesses and public buildings to comfortable levels.  Increasing demand generally means higher prices, and in times where the stress is severe, the imposition of a “brown-out” or even a complete short term loss of power is possible.   

In our gardens and landscapes, increased heat can affect the overall health of plants and lead to specific problems, such as water stress, sunburn and leaf tissue damage.  Insect pests, such as whiteflies, whose life cycle is temperature driven, can cause significant problems when their fast growing populations overwhelm a plant’s natural defenses.

The increased heat can also affect local food and fiber production.  Examples include the adverse effect of heat stress on dairy cows and the potential for heat injury to cotton boll production.

So, what can be done?   Houston, Texas has an interesting program called ‘Cool Houston”.  In their program, they advocate the use of cool roofs, cool paving and trees and other vegetation.  You might want to check out their website at http://www.harc.edu/harc/Projects/CoolHouston/. 

Roofs of buildings generally are completely exposed to the harsh sunlight, unless they are protected by the shade of large trees.  The use of highly reflective, lighter colored roofing materials can help reduce temperatures by reflecting sunlight back into the atmosphere instead of allowing it to heat the roof, the interior of the attic, crawl spaces and even the interior of the building.  Most roofing companies recommend this type of covering, especially for flat roofs.

Dark surfaces of streets and parking lots absorb considerable heat during the bright, sunny days and re-radiate the heat back into the atmosphere when the sunlight ends at sunset.  Light-colored pavements tend to reflect sunlight and do not heat as much as darker colored pavements.  There is a need to give these hard structure alternatives some thought.

Trees and shrubs are sure to help minimize heat gain in both public areas and in our home yards.  Not only do they shade surfaces, they also give off water vapor.  This process is known as transpiration and it cools not only the plants but surrounding areas as well.  Most of us have noticed the difference in temperature at night as we enter agricultural zones from bare desert areas.  It is the water vapor given off by plants as part of their essential life processes that cause this cooling effect.  Even most low water use plants transpire water. 

Not only do we need to plant more trees, but we can also take better care of those trees and shrubs that we already have.  Healthy thriving trees give much better shade and transpire more effectively than those that are stressed or dying.  Good management now, including the proper care of trees and shrubs, can give us huge returns later in lower cooling bills and in more comfortable living conditions. 

To finish up, let me boil this discussion down into the basics.  Urban warming affects us all.  The key effects include increased minimum daily temperatures throughout the year, a longer warm period and shorter cool period within a given day and an extended hot season. 

While some warming may be impossible to avoid as urban growth overtakes the communities of Pinal County, there are some steps that can be taken to minimize the effects.  Now is the time for all of us to get involved.

If you have questions, you can visit with one of our Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, extension 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Whiteflies in the Fall

Some people tell me that they haven’t seen any whiteflies in their gardens this year, but I can tell you from my own observations that those pesky critters, like the principle villains in a horror movie, are out there right now.

If you are new to the area and unfamiliar with the beasts, look for tiny white insects fluttering in the air during the early morning hours.  The heavy fall flights haven’t quite started yet, but there are plenty of young ones storing up energy and getting ready to do their thing.  We start looking for them as the long summer starts drawing to an end.

The sweet potato whitefly usually becomes noticeable to most people towards the end of the August or early September as they flutter around in the early mornings.  Large numbers can usually be seen through September, depending upon how long the hot weather hangs around.  White, greasy stains on the car or truck windshield are often one of the first signs of heavy whitefly populations.  These small insects eat by sucking plant juices up a tube-like mouth part. Feeding by large populations can seriously damage, stunt or destroy a large variety of garden and landscape plants. 

The sweet potato whitefly was first identified as a serious plant pest about twenty years ago.  A tropical, heat-loving insect, it seems to thrive under desert conditions and is a serious threat to many area plants.  It damages plants by removing fluids and nutrients from the plants faster than the plant can replace them.  When susceptible plants are heavily infested, it is important to water and fertilize more frequently to help offset the feeding damage.  Whiteflies also cause feeding disorders in some plants.

These insects have yellow bodies with white wings covered with a waxy powder.  Other types of whiteflies found in Arizona include the greenhouse whitefly, which thrives in greenhouses, and the ash whitefly, which is found mainly on ash and citrus trees, none of which is as serious a threat to good plant health as the sweet potato whitefly.

Sweet potato whiteflies are small insects, about the size of a pinhead, and while they do not fly as gracefully as other insects, they are adept at moving from place to place.  Their style of flight is a simple flutter that serves to suspend them in the air while they either stumble upon a new host or are blown by the wind to a hospitable spot.  Airplane pilots have reported the impact of whitefly insects on windshields as high as 1000 feet above the ground, sometimes in relatively large numbers. 

Temperature is important to these animals.  Cool weather slows its reproductive rate while warm temperatures speed it up. That is why so many are seen at the end of summer and not during the winter.  They are here in the winter, but not in numbers that can easily be seen.

These particular whiteflies feed on a number of different kinds of plants.  Their host range is fairly large, ranging from vegetables, like lettuce, melons and squash to cotton where they contaminate open bolls of lint with their excrement; a clear, sweet liquid that reduces the quality of the cotton fibers by causing them to become sticky.  They also feed on many ornamental plants. 

Plants growing in the fall, however, are the most devastated when sheer numbers of whiteflies overwhelm the defensive mechanisms of many plants and leave them weak and stunted.  There is good news, though.  If the plants can survive through the summer into periods of cooler temperatures, they will quickly recover as the populations decline.

Whiteflies begin their life as they emerge from eggs laid by adults.  The immature nymphs are the most damaging forms because of the amount of nourishment they need to mature, but all stages, including the egg, pull fluids from the plant tissue upon which they rest.

When the adult whiteflies find a suitable host, such as lantana, hibiscus, grapes, annual flowers, herbs, or vegetables, they lay their eggs on the underside of the leaves, particularly along the veins of the leaves.  The eggs hatch into “crawlers” that move around until they find a good place to feed.  Once they have settled down, they molt and become what look like tiny transparent scales.  The immature nymphs continue to feed by sucking juices from the plant.  Eventually the insects emerge as the winged adults, which fly off to new plants.

Some plants are definitely more susceptible to damage than others.  When whiteflies are numerous, they may be found resting on virtually every plant, but they are not necessarily causing damage.  To determine which plants may have a problem, examine the underside of the leaves for immature nymphs or other signs of these insects.  Although the eggs and nymphs are difficult to see with out the aid of microscope or hand lens, the underside of the leaf will have the texture of sandpaper, and probably will have tiny droplets of sticky plant sap.  Plants heavily infested with immature whiteflies may turn yellow and wilt.  Sooty molds may grow in the excrement, called honeydew, causing the plant to turn an unsightly gray or black color.

Whiteflies have been shown to carry a number of virus diseases of annual plants, but they do not seem to infect trees and shrubs.  If an annual plant becomes infected with a virus, little can be done except remove and destroy the plant.

Control requires a series of steps to suppress the populations.  A good first step is to spray regularly the underside of the leaves on susceptible plants with a strong stream of water.  This helps wash off the young immature stages and even some of the adults.  Now is a good time to start doing that because most susceptible plants are starting to show heavy immature populations.

Insecticidal soap sprays are also a good way to kill the young insects.  The soap clogs up their breathing tubes and melts away the waxy outside layers.  If it doesn’t kill them outright, they eventually die from dehydration.  There also insecticide options available.  If you choose one of these, be sure to read the label carefully because some materials cannot legally be sprayed onto edible fruits and vegetables.  Okay, let’s be real here.  It is pretty tough to control whiteflies and even a combination of these options may not give complete control.  The best we can do is to help our plants limp through to the end of the season.

Perhaps the easiest way to avoid whitefly damage is to simply not grow those plants that are most sensitive to whiteflies, or if they are annual plants, when whitefly populations are greatest.  For example, delay planting fall vegetable gardens and annual flower beds until the second week in October, or until the whitefly numbers have dropped off.

While we do not have a really good method to control these garden and landscape pests, we can take hope that the cooler weather that is coming will slow them down once again.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, extension 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Plants Provide Many Benefits In Our Lives

In a hurry up world where life seems to constantly accelerate and the day-to-day challenges appear to bring ever more stress, plants can impart a sense of needed stability and well-being in our lives.

Not surprisingly, recent scientific studies indicate a strong relationship between healthy people and exposure to plants, both indoor and out.  Here are some examples taken from a series of articles published in the January-March 2000 edition of  “HortTechnology”, a quarterly journal for horticultural professionals.

The first example comes from one of the earliest studies looking at the beneficial effects of plants.  Patients having a room with a view of trees rather than a view of a brick wall spent almost a day less in the hospital, used fewer doses of strong pain relievers, and received fewer negative comments from hospital staff on their charts.  The study instantly attracted the attention of both the medical community and horticultural researchers. 

In another study, people in an experiment viewed slides of nature scenes with water and vegetation, slides of nature scenes with only vegetation or slides of urban scenes without vegetation.  When people viewed either of the nature scenes, they exhibited higher alpha brain wave amplitudes than when viewing urban scenes. 

Now stay with me here.  Higher alpha brain wave amplitudes are generally associated with lower levels of physiological arousal and higher levels of attentive relaxation.  In other words, they were judged to be under less stress.  That is a good thing.  The subjects also reported that the nature slides held their attention better than the urban slides, even though all of the slides were judged to have similar informational content.
           
One study focusing on college students showed that those performing tasks that required deep mental concentration performed significantly better on some tests when they enjoyed a window room that opened out onto a nature scene than those who had views of scenes dominated by buildings and sidewalks.  Nature scenes seemed to enhance mental attention and reduce fatigue.

A 1996 study asked apartment complex residents about domestic violence.  Respondents lived in public housing and could not choose their apartments.  Some were assigned to live in complexes surrounded by trees, while others were assigned to buildings without green surroundings.  When asked if they had engaged in violence during the past year, 22% of the women interviewed from the apartments without trees said “yes” while only 13% of the women in the apartments surrounded by trees said “yes”.  When asked if they had hit their children in the past year, 14% from the non-green apartments said “yes”, while only 3% living in apartments near trees said “yes”.  

The list of studies goes on and on, here in the U.S., and around the world.  The evidence is quite clear.  Scenes associated with plants can reduce stress, speed healing, enhance workplace productivity and improve the human outlook on life.  

These results have not gone unnoticed.  Around the world, plants are showing up more and more inside public buildings, in malls and in hospitals and long term care centers.  School gardens are being planted and cared for.  Adults working in the court systems assign juvenile offenders to work in community gardens.  Horticultural therapy has become a viable tool in the medical field. 

These real benefits, however, are sometimes masked, covered up, if you will, by the very challenges of life that make our involvement with plants so essential.  The bottom line is that we are becoming too busy to garden, to care for house plants and to plant trees and shrubs. 

If we do install landscapes, we often give in to the temptation to make them so labor-free that we do not find the need to interact with them in any way other than in the most brief of encounters.  This may be helpful in our busy worlds, but it is expensive in terms of the very real benefits that could possibly be ours.

So, what can you and I do?  There are several ways to enhance our interaction with plants and to improve the surroundings in which we live.

First, bring plants indoors.  Look around the interior living space and search for locations where an indoor plant might fit.  Identify  locations where light, humidity, and temperature conditions fit the needs of the plant.   For example, do not place a boston fern in an area where the cooler or heater vents would blow on the plant and dry it out.  Ferns like moist, humid areas such as in the shower or bath. 

Group indoor plants into natural appearing arrangements that give a sense of the outdoors from which they came.  Such arrangements help create a peaceful, natural feeling similar to that experienced in native environments.

Second, search for ways to make outdoor landscapes user friendly.  Arrange and install outdoor landscapes with the intent that they will encourage human interaction.  Select plants that fit the specific needs of the landscape and of the people that will use it.  Let the landscape be an extension of the home so that it will be an easy and natural step to exit the home and immerse oneself in the outdoors.  A well designed and maintained landscape will entice people indoors to move outside.

Consider placing benches or chairs in strategic locations that invite a passerby to linger and enjoy the setting.  This may be tucked away between trees or behind shrubs away from busy traffic areas, or it may simply be next to favorite flowering shrubs or garden areas.  Such locations encourage introspection and relaxation from busy schedules.

Third, notice the use of plants and natural environments in public places and recognize them for what they bring to those who visit those areas.  Many malls, for example, spend considerable resources to bring the natural environment inside for a peaceful, if not restful, shopping experience.  Encourage businesses and other establishments that you frequent to consider installing plants into their decor.  Tell them about the potential benefits that could come both to them and their customers from the practice.

Fourth, become active in neighborhood and community beautification committees, school garden projects and community garden efforts and encourage the proper use of landscapes and indoor plants in all areas.  Volunteer time not only lifts those served, but also reaps benefits to those serving.

Finally, become informed about plants and the potential benefits that come from human interaction with plants.  Know how to properly select, install and care for indoor and outdoor plants in our harsh, desert environment. 

Healthy plants in our living environment can help all of us accrue actual emotional, physical and psychological benefits each and every day.  The bottom line is, plants help us live better lives.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

The Tecoma Leaf-Tier

Last year was the first year that we saw the Tecoma leaf-tier here in Central Arizona.  It came as quite a shock to us at that time because samples started coming in from all over the county, all at the same time.  Not only that, they were also being seen in Phoenix and Tucson.

We were able to identify the insect and learn about its biology.  We also were able to work out management recommendations.  We wondered if the insect would be able to become established in our climate and decided to take a wait and see approach.  That question has now been answered.  They are still here and doing their thing.  You guessed it.  Samples are coming in as we speak.  If you are growing one of the Tecoma species, let me provide a little background information on this insect pest, what to watch for and what to do if you find the feeding damage.

The insect pest is commonly know as the leaf-tier.  Antigastra catalaunalis is the scientific name.  It is a member of the pyralid family. 

It is important to know that the insect feeds primarily on yellow and orange bells, Genus Tecoma. 
Are you familiar with the tecomas?   “Landscape Plants for Dry Regions,” by Warren Jones and Charles Sacamano, recommends four separate species of Tecoma for our area.  Tecoma alata is commonly known as orange bells or orange-flowered tecoma.  The Argentine tecoma is Tecoma garrocha.  Tecoma stans angustata is the narrow-leaf yellow bells, sometimes called the narrow-leaf trumpet bush; and the fourth is Tecoma stans stans, or the Mexican yellow bells.  All are shrub-like plants.

The tecomas are fairly common in area landscapes.  We like them because they are drought resistant; produce large, showy flowers and, until last year, were pretty much problem free.

The samples are all the same. Instead of a healthy green, many of the leaves are a pale tan where the leaf tissue has been eaten down to a thin, almost transparent layer.  On some plants, the damage can be fairly heavy; in some cases as many as one-half of the leaves showing symptoms.  Some leaves are folded over and sealed with webbing.  No, not spider webs.  The webbing is more dense, like a protective covering that some moth larvae use to protect themselves.  The webbing is speckled with small, black fecal droppings.  In the business, the name we use to describe these droppings is frass. 

The webbing and the frass are a dead giveaway that the insect is a moth and the treatment of first choice for these caterpillars is pretty straight forward.  In almost all cases, we recommend the use of an environmentally safe and organically approved bacteria-based insecticide called Bacillus thuringiensis, or “Bt” for short.

Bt is the active ingredient of a pesticide approved not only by the Environmental Protection Agency but also by organic standards for moth larvae feeding on landscape, ornamental and vegetable plants.  It causes a bacterial disease in the larval stage of the insect’s development.  Once they pick up the disease organism, and it begins to work, the animals stop feeding, get sick and die.  It is generally pretty effective and altogether safe for other animals and plants, including humans.  We use it in many situations and, like I said, it is usually a good choice for moth larvae pests.

If you find symptoms on Tecoma, first determine the amount of damage that you are seeing.  If it is only one or two leaves, you may want to hold off on taking action.  I recommend that you take a "wait and see" attitude. Plants can take a lot of feeding damage without significant harm.  If the symptoms of damage continue to get worse and you need to use a  chemical control, use a Bt subspecies kurstaki product at the maximum labeled rate. The caterpillar's habit of protecting itself with webbing and folded leaves means that contact insecticides, insecticides that you spray onto the insects themselves, will probably not work.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, extension 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu