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