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Sunday, September 14, 2014

Tree Replacement for Ash

Q. I am particularly having trouble with a tree to replace the ash trees that doesn’t grow so tall and does well in our climate. We took out our ash trees because they were giant and the roots were all at the surface. I am now guessing we have a soil issue?

A. I no longer recommend ash trees for our climate. We have had too many problems with them over the years.
There are a number of smaller trees that work well in our climate. It is hard to give you direction without us going back and forth a lot. It is simpler if you go to a nursery and develop a list of four or five trees that appeal to you and I can help you narrow them down.
Shallow roots usually indicate a very heavy soil or shallow irrigations or both. Planting in our desert soil requires a lot of soil preparation where the tree is to be planted. That is a major key to success.
The second major key is irrigation, both the proper amount and the timing when to apply it. Make sure your trees receive enough water each time they are irrigated. Space near irrigations far enough apart so that the soil drains adequately before the next irrigation.
Thirdly, I would include in that using a surface mulch of wood chips after planting. Although not needed for all plants, woody plants that are not from desert climates do much better if a surface would mulch is applied.
I can hardly wait for the criticism on this list! Please, let's make comments constructive. Medium sized tree, tolerant to at least 20F.

Some possible replacements for ash:
Fruitless olive (allergy problem)
Chinese pistache (large tree)
Evergreen elm (large tree)
Carob (slow growing)
Goldenrain tree
Texas ebony
Sweet Acacia (thorns)
Oleander (tree form)

Some Mulches and Plants Bring Bark Scorpions Into Las Vegas

Q. I am hearing that some of the palms and rock are bringing in scorpions. 

Learn About Bark Scorpions and Control Here

A. It is very possible that bark scorpions are being transported here on plants and nursery materials that are coming from desert climates where bark scorpions are common. If plants and nursery materials are coming from places where bark scorpions are not common, then they are probably not going to be a problem.
          I have heard the same comment made about landscape mulches. Those mulches originating from nondesert areas most likely do not contain scorpions. That doesn’t mean they can’t be infested once they arrive here.

Check to see where your plant materials and mulches originate from. If they come from locations that do not have bark scorpions then these plants and materials are not part of the problem.

          If you have some concerns about bark scorpions then investigate your landscape in the evening hours with a black light to see if their present. Many common insecticides used to control spiders are very effective in controlling bark scorpions.
          Now is a good time of the year to make a foundation spray around the perimeter of the house to establish a barrier that these critters are less likely to cross. In the next month outdoor critters will be trying to stay warm and looking for food. Your warm house during the cool evening or night is a magnet for drawing all sorts of critters.

What to Do with Huge Sansevieria in the House

Q. We have a monster Sansevieria plant we have kept for many years.   It’s in excellent health, but threatening to take over the entire room.   It has become so big and heavy that we don’t know what to do with it now. We believe it should probably be re-potted, but an even bigger pot is going to be impossible to move. As it is, we are going to have a rough time getting it out of the house to re-pot. What suggestions might you have as to how to handle, or what to do, with this guy?  It now sits on a table in front of a west-facing window with solar screens.
Sansevieria, Snake plant or Mother in law tongue. This is a huge indoor specimen.
A. You do have a monster plant. It looks like a variety that gets fairly big but if this plant had more direct sunlight it would probably be slightly smaller. However, it's a beautiful specimen. You might have to find a place for it on the floor rather than on a table. It has nice verticality.
The choices you have are to divide it and repot it or to take leaf cuttings and start the plant all over again. As you know you can't really cut it back and still have it look good. I searched online for a video that you could watch on how to divide this plant. Dividing the plant will result in a much smaller plant in diameter but will not do much about the height unless you focus on parts of the plant that you repot that are smaller. I would suggest that you try to get it into a place with more light which should help keep it smaller.
This video should help you in figuring out how to divide it. I am sorry it is in the Czech language but the video is easy to follow without the words.
Notice how he breaks it apart with his hands. You can do that or you can take a sterilized knife and cut it apart into smaller clumps. This plant spreads underground by rhizomes or underground stems. Cutting or severing the rhizome results in separate clumps that you can repot. I would just the cut ends with a fungicide such as Thiram or just let them heal over in a safe place inside the house for about 24 hours. Then you can safely replant them without a lot of fear of disease entering the cut wounds. You can replant as many of the clumps as you want to to fill in the container. You can select the clumps that fit your need and dispose of the others or give them to a friend.
You can propagate this plant very easily with cuttings from the leaves. This video will show you how to take leaf cuttings.

Grape Leaf Skeletonizer Attacks Again!

Q. For the second year in a row, my grape plants were decimated, but starting right before ripening, and continuing throughout the summer.  I sprayed a soap spray on them, but to no avail.  I thought the problem was a slow flying black fly, but then I noticed a blue and yellow caterpillar type bug on one of the leaves.  What can I use to prevent this from happening again, and will they threaten my peach trees (not so far) Attached are a couple of photos.  The match book is for size comparison.

A. This is the grape leaf skeletonizer. Here are some posts on my blog that address this for Las Vegas.
Let me know if you have trouble seeing these.

Ants Now Invading Garden Beds

Q. We have two 4x12 garden beds made out of cinderblocks that we built last fall. We used soil from Viragrow and had great luck with the vegetables that we planted.  The eggplants and strawberries are still producing. Our back yard is just gravel so the only water is the bed irrigation. We have noticed a lot of ants on our property this summer (the tiny red ones).  They have now invaded our garden beds. I'm not sure what to do to get rid of them because i don't want to use spectricide or another harmful pesticide like that in our garden soil like I use in other areas of our property.  What should I do to get rid of them?

A. The best thing to do is to treat the nest where they're coming from. I like a product called Amdro which you can buy in nearly any nursery outlet including Lowe's or Home Depot.
This is a bait which is taken back inside the nest or it will kill the Queen. It must be kept dry and sprinkled close to the nest. Trace back to where he the ants are coming from and sprinkle a tablespoon or less around the mound that enters the underground nest.
Keep this product dry after you apply it or it will not work. It can be used in organic farm operations as long as it's not applied to the crops so it is a relatively safe product to use rather than sprays. Good luck.
Another product that works well as a spray is Prelude or products containing permethrin insecticide.

Why Is the Bark Splitting on My Bottlebrush?

Q. Do you what is causing the bark and stems of my bottlebrush bush to split and die on the East side?  Here are a few pictures.  I don’t see any pests.  Overall, the bush is healthy (except for a few of the branches which have bark that is splitting) and it has a lot of new growth and leaves.  Only the older branches are splitting in some spots and then entire the branch dies (top to bottom). I would estimate that only about 20% of branches/limbs have bark which is splitting. The bush was planted about 4 years ago and was purchased in a 5 gallon container. I haven’t changed the water frequency or the fertilization schedule.

A. From your pictures the splitting does appear to be on the side most open and in this case the East side. To get sunburn it doesn't take that long of intense sunlight, maybe 20 or 30 minutes.
If this damage extends more than halfway around the upright stems then I would consider cutting them back. You would cut them back to remove this highly damaged area. These cuts might be quite deep inside the canopy.
That's okay because the shrub will come back and it will come back quickly to the size before. The roots will be large enough to push a lot of new growth back to its original size, then it's growth will slow down again. I would make these cuts probably around late January or February 2015.
Make sure you have enough drip emitters to provide the water that's needed. This plant does not like to be watered daily, so avoid that.
These plants tend to get yellow or iron chlorosis so I would supply either a soil application of a good iron chelate such as EDDHA or 138 iron chelate.
You can do the same thing with multiple sprays of a less expensive iron product what it might take several sprays to get much greening out of the sprays.

Fertilize after you prune this rub with an all-purpose tree and shrub fertilizer. One application a year is enough.

Palm Trunk Problem at the Base

Q. My palm trees in the back yard seem to have a problem with the trunk next to the ground.  Not sure what is wrong, too much water, bugs, I need help.  These are large palm trees and I would not like to lose them.  I have attached some photos.  I have four large palm trees with this problem.

A. This is typically not a problem for palms because there biology is different from most other trees.
Because palms are monocots a lot of this so-called wood from the outside can slough off without much of a problem. In fact what you are seeing is fairly common.
Make sure when you irrigate these plants that you keep the water away from the trunk and do not water them daily. I would be watering them about 2 to 3 feet from the trunk, not up close to the trunk. These should be watered like any other nondesert tree.

Leaf Cutter Bees Destroying Leaves on Roses

Q. We have six rose bushes in our yard in Centennial Hills that have been attacked by cutter bees. The leaves have been decimated on our rose bushes. While they don't seem to destroy the roses on the bushes, they were leaving a path of destruction on almost every single leaf on our rose bushes. We tried everything but to no avail. In fact, several "remedies" we tried, which we found online, seemed to harm the bushes and didn't even phase the bees at all. We've learned these bees are indestructible and NOTHING works to kill OR discourage them to go elsewhere!! They have somewhat subsided for now but their destructive behavior lasted for several months; from spring through early August. Our rose bushes are starting to recover but we know next spring they'll be back!! Any suggestions???

A. I have talked about these guys on my blog so I would like to direct you there.Yes, they can be destructive but there are also extremely good pollinators for our vegetable and fruit crops. Somehow we need to find a balance between their benefits for ourselves and our neighbors while minimizing or distributing some of their damage. The Leafcutter bees are gathering nesting materials for making babies.

Gardening Classes at Acacia Park in Henderson

October UNCE gardening classes at Acacia Park
Free and open to the public, all classes begin at 9 a.m.

LAS VEGAS, Nev. - Southern Area Master Gardeners—for the 10th year—will offer a series of free classes at Acacia Park in the fall. Classes are offered in partnership with the City of Henderson Parks and Recreation Department and are published in “Henderson Happenings.”  All classes are taught by University of Nevada Cooperative Extension Master Gardener instructors and begin at 9 a.m. Pre-registration is requested by visiting www.cityofhenderson.com/parks and clicking Online Registration.

Native and Adaptive Plants will be presented by Master Gardener Denise McConnell on October 4. Using plants in your landscape that are likely to survive will make your landscape less costly and still be beautiful. This class will include a tour of the Demonstration Garden at Acacia Park. After the heat and wind of the summer, you will be able to see how plants survive and how they can add beauty to your landscape. Master Gardeners will assist with the tours and answer your questions.

The topic for the October 11 class is Crops to Grow by Master Gardener Jeanne Toscano. What edible crops will grow in Henderson? Are there varieties that will grow better than others? Will using seedlings make it easier? Can you still plant tomatoes?  Come and join the discussion and bring all your questions.

On October 18 Master Gardener Novella Holland will talk about Palms, Cactus and Succulents. You can see a variety of palms in the Las Vegas valley and wonder how they would look in your yard.  But even more important is how much work will they require, how long are they expected to live, and what kind of maintenance is required.

Get ready for Trick or Treats on October 25. Master Gardener Loretta Oakes has a few tricks up her sleeve as she introduces kids to festive plant projects as Halloween approaches. All children – young and young at heart – are invited to attend. Early registration is recommended as space fills quickly.                     

Cooperative Extension Master Gardeners will have an “Ask a Master Gardener” table at the Park on class days. Acacia Park is located at 50 Casa Del Fuego (Intersection of 215 and 515) in Henderson, Nev. Master Gardener volunteers are also available to answer questions through the Home Gardening Help Line at 702-257-5555. The Help Line is staffed Monday-Friday from 8 a.m. -5 p.m.                             

Newly Planted Tree Shows Leaf Death and Die Back

Q. About three weeks ago I bought and planted a 12 X12 crepe myrtle tree. I used grow mulch and compost watering it once a day since then. Now the tree branches seem to be losing its leaves. Could I be over watering the tree?  What could you suggest I do to make sure the tree grows healthy? 
Small crepe Myrtle tree, Not the readers

Plant got too dry at the nursery before it was delivered
  • Plant was delivered in an open truck and the leaves were battered by the wind
  • Plant got too dry before it was put in the ground
  • Plant was put into a dry hole and the roots became desiccated or dried out for water was applied. This can happen in minutes.
  • Plant root ball fell apart when it was put into the planting holeSalt levels were too high in the soil or the planting mix or both and not leached with enough water at the time of planting
  • Watering daily after it was planted
  • Not watering often enough or with enough water after it was planted

At the time of planting, the soil in the hole, and all of its contents, should be wet. The soil should be checked to make sure that it drains several inches of water in no more than a few hours. If the soil drains adequately, the hole needs to be dug no deeper than the box.

In our desert soils with extremely low organic matter, it is best to use the soil that was dug from the hole and amend it with a planter mix amendment in a ratio of about 1:1 by volume. To help prevent transplant shock the tree should be planted as soon as humanly possible after delivery.
To help prevent transplant shock further the tree should be planted into a hole that was wet and allowed to drain. The wooden box must be removed from around the root ball at the time of planting.
This is done by leaning the tree over on its side, removing the bottom of the wooden box, pushing it back to an upright position, lowering it carefully into the hole, removing the rest of the box, and adding the backfill.
Box tree planted in the landscape. The bottom of the box is removed before placing it gently into the hole. Sides of the container is removed, the root ball is watered and the amended backfill is used to fill the hole, watering the hole as the backfill is added.

As the amended backfill soil is added to the hole, water from a hose should be running into the planting hole keeping everything inside wet. After planting, a donut shaped basin 4 inches high should be constructed around the perimeter of the planting hole.
Fill this basin twice every time you irrigate for the first two weeks after planting. Fill the basin approximately every three days. I would not rely on a drip irrigation system for delivering the water needed by the tree immediately after planting.
After 2 to 3 weeks you can begin to wean the tree from water applied by the hose and begin to integrate your drip irrigation into your watering cycle. You would do this by putting the drip irrigation on a normal schedule for landscape trees in our climate and continue to fill the basin once a week to supplement the drip irrigation and removal of any high levels of salts from the soils.
Some landscape companies leave the drip irrigation to come on daily to try and accomplish the same thing but that can be dangerous because they don't tell the homeowner to reset the clock or they forget to reset it themselves.

Three things you must regulate when you irrigate: 
how much you apply at each irrigation, 
how often the irrigation is applied and 
the time of day water is applied. 

Make sure your drip irrigation system is applying enough water every time it comes on.
It is difficult to tell you the number of minutes this equals without knowing the number of drip emitters and their gallons per hour rates of water application. The other thing needed is the size of the tree; its height and the size of its container.
How often your irrigation system delivers water depends on the time of year and the type of plant. Trees and large shrubs are watered less often than anything else in the landscape. This time of year we are beginning to cool so applying water twice a week, as long is it is enough water, will be often enough.
Time of day the application is made is the least critical feature. However, ideally the irrigation should come on just prior to the heat of the day.

Prince of Wales Juniper Low Maintenance Solid Green Groundcover

Wednesday, September 10, 2014

Intensive Indoor Crop Production Webcast Today

Presentation today at 4:00 p.m. MST by SPLS student Connor Osgood.  See links below for the Webcast.

"Intensive Indoor Crop Production"
Connor Osgood,  SPLS Student
will offer a special presentation at the
Controlled Environment Agriculture Building (CEAC)
1951 E. Roger Road
Wednesday, September 10, 2014, 4:00 – 5:00 PM

“An Internship Completed:  Experiences in the World of Intensive Indoor Crop Production Using Hydroponics and LED Lighting at a Vertical Farm” 

The presentation will be webcast at:

for attendees without UA ID:

[please allow a few minutes prior to start of the talk  to prepare the Elluminate software]

Contact Dr. Gene Giacomelli, giacomel@ag.arizona.edu  or  Terry Albertson, talberts@email.arizona.edu
520/626-9566 for more information
Organized and Supported by the
Controlled Environment Agriculture Center,
The University of Arizona

College of Agriculture and Life Sciences

Tuesday, September 9, 2014

Why Does My Ash Tree Have Dying Limbs?

Q. I have two, twenty-year-old ash trees that appear to be dying. I have attached pictures. The smaller tree is a Modesto Ash and it started losing limbs about a year ago. The bark is now separating and it looks like an old stump with a few sprouts. The other is a Rayburn Ash. It just began having limbs die this summer but is accelerating. I am also noticing ash trees all over our neighborhood in the same condition. What is happening and what can I do to save these beauties?

A. I'm sorry to hear about your ash trees. This is a fairly common problem with ash trees in our desert Southwest. I have been dealing with this problem, mostly on Modesto Ash, for about 30 years. I no longer encourage people to plant ash trees in our climate.
Plant samples have been sent to several plant pathology laboratories over the years and no one has been able to find a disease problem.
We have been calling it ash tree decline but we do not know why it is happening. Fertilizer applications and increasing the water does not seem to help.
Modesto ash with limb dieback
The trees seem to dieback from a lack of water to some of the limbs but no one is certain why. At this point all I can tell you is to remove them when they get to the point when they become a problem to public safety or they just look bad.
The one in the side yard could have suffered from a lack of water from the picture. Modesto Ash in particular would benefit from wood mulch applied to the surface and given liberal amounts of water.
Check for borers underneath the bark that pulls away from the trunk. I suspect the trees may have been stressed either from the decline or water. This is a prime target for boring insects trying to finish off the tree.Once trees are heavily stressed there is not much you can do to prevent a borer attack to the tree. They will infest the tree and finish it off.

Black Ooze from Eucalyptus Might Be New Problem

Q. I have an ornamental Eucalyptus tree in my back yard that is 20' tall and facing west.  It has been steadily losing leaves and branches the past two years.  There is a black sap that has been oozing sap through the bark. It crystalizes into a hard substances.  Can you provide a diagnosis and treatment?
Not the readers, but this is a eucalyptus and many have a similar form.
A. Your description of this problem about your Eucalyptus bothers me. The loss of leaves, the branches dying back coupled with black sap that oozes through the bark is a very good sign of Eucalyptus borer.
What does Eucalyptus borer look like?

To my knowledge, this insect is not been reported in southern Nevada. It has caused a lot of destruction in Eucalyptus in California.
I would consult this information from California: Information on Eucalyptus borer

I am paraphrasing now from California information:
"Holes in the bark and stains or oozing liquid on limbs or trunks are common symptoms of longhorned borer damage. When this borer is a problem, leaves can discolor and wilt, and limbs can die back."
"Longhorned borers usually attack stressed or damaged plants, leaving vigorous, appropriately watered trees alone. In California, however, many eucalyptus trees are seasonally water stressed during hot summer months, rendering a significant proportion of them susceptible to beetle attack. Tree species with some resistance to these wood borers can produce copious amounts of resin in response to an attack."
"Extensive larval feeding beneath the bark can spread around the entire circumference of a tree, girdling, or completely removing a strip of bark from, the trunk. Trees at this stage of infestation have a thin canopy with wilted or dry leaves, and the bark is cracked and packed with larval excrement. Infested trees usually die within of a few weeks of girdling, although resprouting can occur from the tree base."
What does this borers damage look like?

If you believe this could possibly be the problem I would hope that you would contact the Nevada Department of Agriculture and start asking some questions.They might ask you to send up samples Carson City for identification by the entomologist. This borer usually attacks trees that are not getting enough water or are not being watered often enough or both.

Nevada Department of Agriculture in Las Vegas: 702-486-4690

Don't Pick Pink Lady Apples Yet

Q. I have a Pink Lady apple tree that is very young with about 6 apples on it. They are green.  How do I know when to pick them?
Pink Lady apple in late November
A. The fruit will ripen all on their own. Wait until at least mid-November before picking them for best quality and highest sugar content.
Hopefully you thinned them to get good some size and kept watering them when needed so lack of water does not affect their size or development.
Pink lady Apple fruit stays green for a long time until it's ready to harvest. The brown spot on the green apple is due to a puncture wound

They can hang on the tree until about mid-December but by Dec 1 you should be thinking of harvesting them. Harvest earlier than this if you start to see bird damage.

What Lawn Grasses Can You Grow in Las Vegas?

Here is a chart of turfgrasses that can be grown in southern Nevada at the lower elevations. Not all of them will be available locally but many can be ordered over the Internet. Hopefully this will give you a basis for comparison when selecting a lawn grass.

If you have any further questions on selecting a lawn grass for our area, send me an email at extremehort@aol.com
For instance, be very careful if you are selecting Buffalograss.

Don't Use Containers to Store Plants until You Move

Q. I'm new to Nevada and currently renting a house.  I'm looking for plants that can stay in containers for at least a year, as we plan to take them when and if we move. I tried to grow some herbs, an eggplant, cacti, flowering plants and they all died.  
Strawberry's and vegetables grown in containers at Viragrow
A. If you are renting I would certainly encourage you to focus on annuals that you can use. I would not encourage you to buy fruit trees or landscape trees now and keep them in containers for planting later when you move.
You are better off buying those plants when you are ready to put them in the ground. There is just much too high of a risk that you'll lose them before you plant them.
If you are fond of cooking and focus on some vegetables and herbs that you would be using for cooking. I would not use containers smaller than 5 gallon unless they are cacti are succulents.
The small containers just do not hold enough water for these plants to make it through the summer months. Be prepared to water them daily. Use a good container soil when planting and avoid the cheapest soil you can buy.
Fruit trees and landscape trees never do well stored for long periods of time in containers
Most plants usually do better with an Eastern exposure rather than a southern or Western exposure. In the wintertime annual plants will frequently do better in the south and west exposures.
Take a look at my blog and do some reading up on growing container plants here.

Tricks to container gardening

Red Bird of Paradise Is Poisonous but….

Q. You had a post on your blog about red bird of paradise. posting on my blog
Will this bush hurt my dog?  I don't think she would grab the flowers.  I want to grow a big bush in this area of my back yard as my deceased husband loved the flowers.  I heard the bush is poisonous.
Flower of the red bird of paradise
A. Like so many plants, the dose makes the poison. Yes, this plant if it is taken in large quantities would be poisonous to dogs, cats, humans, etc.
However, I would point out to you that this plant is also sold, the leaves and stems primarily, for Ayurvedic medicine and has been found by researchers to have antiulcer and anti-inflammatory properties.
Please keep in mind that about 80% of all landscape plants are poisonous. Some are more poisonous than others. Take as examples oleander and the castor bean plant.
Many of our houseplants are also poisonous such as mother-in-law's tongue or snake plant and many others.
All I can tell you that in small quantities I would not be too concerned. However if an animal consumed a lot of the plant it might cause harm or worse.
My former floriculture teacher once went on television around Christmas time and demonstrated by eating the leaves of Poinsettia that it is not poisonous in small quantities. The white milky latex found in the plant may cause some burning but it does not kill you as the press has portrayed.
I will not tell you that it is non-toxic and not to have some concern about it but on the toxicity list I would probably put it as mildly toxic and keep your pets away from it if they tend to chew on things. I would also not use the flowers as a garnish for a meal.

Wednesday, September 3, 2014

Tanglefoot and Plant Damage

Q. I recently purchased the product Tanglefoot for ants around my pomegranate tree however after reading the directions, it states not to use it on fruit trees. Is it ok or should I get something else?
Tanglefoot used on Peach tree
A. Tanglefoot is a product that can be applied to the trunks of trees and vines. It is like a petroleum jelly or “grease” that stops insects from climbing the trunk with a sticky barrier they cannot cross.
We have used Tanglefoot on fruit trees with no problems. From the manufacturer, "Do not apply directly to young, thin-barked trees or to bearing fruit or nut trees."
Sometimes Tanglefoot applied to the trunk can cause the trunk to overheat if it is in the sun and scorch and girdle it. It can also prevent thin barked trees from "breathing" through the holes or lenticels in wood that has not yet formed bark.
It can be a problem for young thin barked fruit trees, mostly the stone fruits. Apply to older fruit trees per the label.

Almonds Black On the Inside

Q. I've begun my almond harvest and have found black substance on the inside of some of them. It is almost like soot. Do you know what it is and is it toxic? Should I wash it off or throw them out?

A. You didn’t say if it was inside the nut (kernel) or just on the husk. I am assuming it is only on the husk because this is much more common. If this mold is on the nut, discard these infected nuts and do not contaminate other nuts. This reduces the potential of a mold “toxicity” to humans due to aflatoxins.
Yours is most likely one of the “bread molds” infesting the husk or hull and probably developed due to recent rains and high humidity. The nut is safe to eat if not infected. Normally hull rot, as it is called, is not as common here as it is in more humid climates where it can actually attack fruiting portions of the tree and cause a decline in production.
Hull rot is accentuated if you apply too much water and nitrogen fertilizer to the tree. Let them get a little “hungry” for fertilizer and start applying less water to them 4-6 weeks before harvest (skip an irrigation day). If this problem will probably not continue in future years unless it rains again during nut hardening.
Harvest the nuts, dry them out, remove the husk and inspect the nut when you open it. If the nut is infected, discard these nuts and wash your hands.

Whiteflies Destroyed Vegetable Crops

Q. I am new to gardening in the desert and am surprised at my success thus far!  That is, until the whiteflies came. It is August and they are on EVERYTHING!!  I started with insecticidal soap on the undersides of the leaves and I see dead flies there. I am getting ready to plant all new Vegetable crops for fall but need to get a handle on these flies before subjecting new plants to these insatiable pests.

A. Whiteflies are a very tough insect to control once they get established in the numbers you are talking about. Females lay a couple hundred eggs at a time and these hatch and develop into sexually mature adults in about six weeks.
Whiteflies on pomegranateNoticed they are on the bottom sides of the leaves.
Conventional pesticides have not been very effective on whiteflies due to the development of resistance to applied pesticides. Now we rely on a more integrative approach to try to get a handle on controlling them.
This includes the use of oils and soaps when temperatures permit, yellow sticky boards that are renewed on a regular basis, reflective mulches such as aluminum foil, planting trap crops such as squash, hand picking heavily infected leaves early in the season, hand vacuuming, and others.
Yellow sticky trap in greenhouse.
You need to stay on top of this pest early in the season if you expect some control. Their numbers explode when it gets hot. When plants are still small, remove the bottom leaves close to the ground. These usually get infested first and they are impossible to spray on both top and bottom sides of the leaves which you must do.
Get on a regular spray program at their first sign, alternating with soaps and oils. Spray at least weekly both the underside and tops of the leaves. You will need a backpack sprayer if you have lots of plants or you might consider purchasing a fogger to apply pesticides.
Solo backpack sprayer
Foggers are quite effective but must be used when there is no wind. Use yellow sticky cards supported over the crop and replace it weekly. These can be used to help predict when to spray.
Trap crops that attract whiteflies, like squash, may also help. Squash plants strongly attract whiteflies and help to deter them from infesting other crops in the garden. Sometimes it may be easier to remove severely infested plants and replant.

Crabgrass Control Now?

Q. What steps can be taken this time of year for crabgrass invasion?
Crabgrass, not the readers.
A. It is now August. If you correctly identified your weed as crabgrass, there is nothing that you can do now except remove them by hand or do some hand weeding. Crabgrass will die when it freezes hard this winter. If it is in a location where it does not freeze, or lightly freezes, then it will survive and grow more the following year.

All you can do this time of the year is soak them with water and pull or rogue them out.

You can also burn them back if it is allowed. Propane weed flamers or torches work well if you use them in an area that will not continue to burn. The seed, however, will still be there on top of the soil and unaffected. The seed germinates in the spring around the middle of February in our climate or perhaps earlier if it is warm. I purchased one for weed control on my small farm in the Philippines. The more powerful ones like mine will even weeds that are wet or after a rain. Very important in the Philippines.

Flame weeder I purchased

Pre-emergent herbicides or weed killers can be applied about the middle of January to prevent crabgrass from germinating and getting a foothold. It should be reapplied about six weeks later or when the label tells you to. But this time of the year, all you can do is pull, burn or dig them out.If you buy a pre-emergent weedkiller for crabgrass make sure it lists crabgrass on the label, destroy any crabgrass that survive past the end of January and apply this herbicide by mid-January in our climate.

Controlling Frogeye Disease in Lawns

Q. Can you tell me why lawn grass gets frog eyes and the best way to prevent it? Also why does some of the grass look so yellow?
Summer patch, frequently called frog-eye or frogeye patch.
A. This is the time of year we usually see frogeye disease, or Summer Patch, in lawns. This used to be called Fusarium many years ago, but no longer. The yellowing may be due to a lack of nitrogen or iron fertilizer or both.
This disease is a hot weather disease on tall fescue in the Mojave Desert. It occurs when air humidity increases in the summer months or if we water our lawns early in the evenings.
Consider the disease organism to be present on all tall fescue lawns. The symptoms of the disease appear during hot, humid weather or during a rainy period. The worst scenario is if it rains in the afternoon or early evening and keeps the lawn wet during the night.
If our lawns stay wet for at least six hours at night in July and August, this tends to promote this particular disease. The disease will take about 3 to 4 days to appear when conditions are right.
Apply a preventive fungicide if your lawn has been susceptible to this disease in the past. If it has, you need to plan that it will happen again. Purchase a lawn fungicide that prevents frogeye disease, a.k.a. Fusarium or summer patch and states so on the label.
Apply it to susceptible areas 2 to 3 days after summer rains occur. Follow label directions for reapplication of the fungicide. Lawn fungicides aimed primarily at disease prevention and seldom cure diseases once they start.
Fungicides will stop a disease from spreading once applied but seldom cure it.
Nonchemical control includes aerification of the lawn in spring or fall months. Increase the mowing height or make sure lawns are mowed at 2 1/2 inches or higher. Make sure the irrigation has head-to-head coverage and prevent it from getting water stressed during the heat.
Use organic fertilizers on the lawn including composts and bagged manure products. Compost applied as a fertilizer has been shown to reduce many lawn diseases. Compost should be applied monthly during the growing season. Use mulching mowers and leave the mulched clippings to decompose in the lawn and on top of the soil.
Those of you living in Las Vegas can get compost for top dressing lawns in bulk at Viragrow.
Viragrow website

Globe Willow Is Frequently Short-Lived

Q. I have a five or six year old Globe willow tree that is dying limb by limb.  I just noticed that some limbs are covered with some kind of beetle that are about the size of my thumb. They do fly and are a little green in color. I did started spraying with Sevin insecticide.  Is there something else I can do? 

If you don't know what Globe Willow looks like

The one pictured above is 'Navajo' Globe Willow, popular in the Western states.

A. Globe Willow does not have a terribly long lifespan in our climate. If you look around, you don’t see very many old trees.
Borers are quite common in willow in our climate and cause them to have a short life span. The usual symptom of borers in Globe willow are limb dieback, causing the tree to die further and further each year.
Globe willow is disease susceptible. Slime flux disease is a problem it faces and can attract insects that feed on the sour bacterial ooze that comes from infected limbs. In short, I think you are treating a symptom and not the problem.
I do not suspect that these beetles are associated with the borers but, without a picture, I could be wrong. My best suggestion is to remove it and plant a different tree if you plant one at all.

Horticulture Newsletter for Northeast Clark County, Nevada

Those of you readers that are living in and around East Clark County, Nevada, might consider subscribing to a newsletter that was developed specifically for you by Nevada Cooperative Extension. I provided a link back to its source.

September Newsletter for Northeast Clark County, Nevada

Desert plants: Jojoba

Andrea Meckley, Certified Horticulturist

Description:  Evergreen shrub
Mature size: 6 feet tall x 6 feet wide
Water use:  low
Exposure:  all day sun
Origin: Sonoran Desert
Uses:  Hedge, screen, or foundation plant
Hardy:  to 15 degrees F

Despite its scientific name Simmondsia chinensis, jojoba does not originate in China.  The botanist Johann Link originally named the species Buxus chinensis after misreading a collection label "Calif" as "China".  This hardy shrub has leathery grey-green egg shaped leaves and the female plant produces edible nut-like fruit.  Jojoba provides year-round food for many animals, including deer, javelina, bighorn sheep, and livestock. The nuts are eaten by squirrels, rabbits, other rodents, and larger birds. Only Bailey's Pocket Mouse, however, is known to be able to digest the wax found inside the jojoba nut.  The name "jojoba" originated from the O'odham people from the Sonoran Desert who treated burns with an antioxidant salve made from a paste of the jojoba nut.   In large quantities, the seed meal is toxic to many mammals, and the indigestible wax acts as a laxative in humans. Jojoba nuts contain more than 40 percent “oil,” which is actually a liquid wax. The wax is highly resistant to oxidation and is stable at high temperatures. These properties make it a very high quality lubricant, equal to sperm whale oil. Only sperm whale or jojoba oil is acceptable for some industrial applications. The wax is also used in cosmetics. For these reasons and because sperm whales are endangered, jojoba is being developed as a commercial crop in several countries.

Leaves of Crepe Myrtle Yellowing

Q. The leaves of my crepe myrtle are turning yellow some show signs I think of a specific mold on underside of the leaves. Please advise in your usual expert advice.

A. When yellowing occurs at the tips first it usually indicates a salt problem. This is possibly due to a lack of water or not enough water applied during an irrigation. It is also possible water is not delivered often enough so the soil becomes too dry between waterings. It is also possible it might be watering too often and not letting the soil dry between waterings.
Crape Myrtle growing at the research center with wood mulch, annual applications of complete fertilizer, iron EDDHA and foliar application of Miracle Gro
Look closely at your watering habits. If you are watering by drip make sure you put lots of gallons down every time you water. For trees this is gallons of water applied each time. The number of gallons depends on the size of the tree. As the tree gets bigger it needs more water applied at each irrigation. NOT watered more often.

Make sure when you water that it is not daily or even every other day. This time of year every three days is adequate but put enough gallons down, not a small amount.

Estimate how much water is delivered each time you water. You can use the chart below if you do not know the gph (gallons per hour) of your drip emitters. For instance if your drip emitter delivers 10 ml of water in 9 seconds then you have a 1 gph emitter. Increasing the total water applied will flush salts from the tree.

Number of seconds to deliver gph (3600 seconds/hr) (3785ml/gal, approx. 4000)
Gph     10ml     20 ml    30ml    40ml     50ml    60ml    70ml    80ml    90ml    100ml
¼           36 sec. 72           -           -            -           -           -           -          -            -
½           18       36        54         72
1            9         18        27         36           45       54         63         72
2            4.5       9         13.5      18           22.5
3            3          6           9         12           15
4            2.25     4.5        6.75     9            11
5             -
6             -
7             -
8             -
10           -            -            -           -           4.5      5.4         6.3       7.6        8.1       9.0

If you suspect you are watering too often then increase the number of emitters (this way you do not need to increase the minutes). Increasing the minutes means everything else will get more (or too much) water.

If you suspect you are not giving enough water each time then flush the soil with water several times to remove excess salts and rewet the rootzone deeply. Put a hose at the base of the tree and let the hose run very slowly around the tree near the emitters for several hours. Or build a donut around the tree and fill it several times a few days apart. Or buy a small inexpensive sprinkler that goes on the end of the hose and let it run for 15 to 20 minutes. Repeat every other day three or four times to flush salts.

This could also be from a lack of organic matter in the soil IF the tree is surrounded by rock mulch. Buy some decent compost and apply it to the rocks under the tree and water it in thoroughly. Do this two or three times this fall and repeat it in the spring.