We Have an Ocotillo Competition Going!

Cathy and Bill think they have the largest ocotillo in Las Vegas. Does anyone want to challenge them? It is about 22 feet tall. Keep your eye on this posting. I will update it as I learn more.

Orange Tree Dropping Fruit

Q. My orange has lots of blossoms, they begin to set the fruit, but when the fruit becomes the size of a pencil eraser, the fruit drops off the tree. What is going on? I watered it, and applied fertilzer.

 

A. I have two questions that might shed more light: 1. Is this tree planted less than three years ago? and 2.  Is it a Navel type orange?

Sometimes it takes a few years for the plant to come into enough maturity to set and hold the fruits. . . . And dropping fruits is a common complaint with Navel Oranges. . . They set fruits and when the heat hits or the first dry wind and they slough off most, if not all their fruits. . . With time more and more will fruits will make it to maturity. . .. Most people are disappointed with the quantity of Navels but not the quality.

 

Terry Mikel

Yellow Vomit-Like Thing Could Be Mushroom Related

Q. I found this thing in the picture I sent to you under my Joshua tree this morning. It is about 6 inches long?  Is it mold?  I only water three times a week for 5 minutes

Yellow "Thing" Under Joshua Tree

A. I get a picture of this once a twice a year, usually in the spring when it is cooler, there has been rain and there is plenty of wood chips for it to feed on. This is called a slime mold. Kind of resembles vomit.

Slime mold on wood mulch at the orchard.

They can range in colors from yellow to orange and are related to mushrooms in a very loose sense. Like mushrooms they are a decomposer and feed off of decaying organic matter like wood mulches or undecomposed organic matter in the soil. We see them in the orchard a lot feeding off of decaying wood mulch.

Slime mold in a lawn. It is feeding on decaying grass either as thatch or clippings or both.

No treatment is necessary. It is a good guy since it breaks down woody debris. Does not attack living plants. If you want to be an industrialist, destroy it with the back of a rake and rake it into the mulch and soil. It will probably come back at some time but like a pest would but it is a pest only because we are afraid of it. I will post pictures of some on my blog.

Fungus Gnats Can Be Controlled With Special Bt Formulation

Q. I recently transplanted two house plants and now  have gnats coming out of the soil and infecting my entire house.  Is there any way to kill these little buggers or do I have to get rid of all the dirt and start over? 

 

A. Fungus gnats can be a serious problem with houseplants as they can feed on plant roots as well as the decomposing organic matter left in potting soils. The life cycle of fungus gnats (egg, larva, pupation and adult) are fairly short, perhaps two to three weeks.

The destructive stage is the larva or worm stage. The pesky stage is the adult which can fly and be bothersome. These stages are overlapping so they will not all be flying at once but some will be in the egg stage, some in the larva stage, some pupating and some flying.

You can attract the larva living and feeding in the soil to decaying vegetable pieces like small pieces of potato. You can lay pieces about the size of a French Fry on the soil surface and these larva will start feeding on them. You can collect these pieces and dispose of them and it will help get rid of a few of the buggers.

Let me point you in the direction of an organic product that may work for you. This is supposed to be available at hardware stores and home improvement stores. It was originally labeled for controlling mosquitos but is now approved for fungus gnats.

This is an “organic” product made from Bt (a bacterium) with a homeowner trade name of “Mosquito Bits”. There have been a few other homeowner products made from this Bt for indoor plants in the past but they have disappeared from many marketplaces I assume because the homeowner didn’t know about them and how to use them.

Mosquito Bits is a formulation of a special Bt for controlling fungus gnats.

A word of explanation. As I said, this is a Bt product. I have mentioned Bt in the past but this one is a DIFFERENT form of Bt so it will not work to use the Dipel or Thuricide product that you would use for grape leaf skeletonizer, tobacco hornworm, tomato fruitworm and other garden pests.

This form of Bt is rather unique to certain types of insects such as mosquitos and fungus gnats. The commercial formulation of this product is called Gnatrol. Apply this product according to the label directions.

 

Below I have pasted a document that explains the different types of Bt and how they might be used.

Since We Cannot Burn Bermudagrass in Early Spring Anymore We Are Forced to Use Equipment to Keep it Looking Good

Q. (Response to an eariler posting I made regarding a bumpy bermudagrass lawn). I have a TruCut reel mower. I think the lawn is flatter than the impression I gave you in my earlier question. The bumpiness might be more from uneven thatch, thus thin spots. I aerated it several times last year. Maybe I need to feed and mow more often. It can also be due to weight imbalance with speed of the mover, thus with a front throw, I notice that when the basket is fuller, the bouncing is less. The lawn has never been as nice as I want. I feel the peak season is short in this climate.

 

A. Las Vegas sits in what educated turfgrass professionals might call the "Transition zone". The US has three major turfgrass growing regions; climate suitable for cool season grasses like bluegrass, a climate suitable for warm season grasses like bermudagrass and this odd area in between these two climates we call the "transition zone". The transition zone is capapable growing both warm and cool season grasses equally POORLY. Kind of reminds me of those tools that are 8 in 1; they can do eight different jobs but none of them very well. Kind of like a Swiss Army knife or a Leatherman.

 

I was just looking again at your response to my eariler email and question on bumpy lawns.  One benefit of overseeding is that the process of overseeding helps to eliminate some of the thatch because you must dethatch the lawn sufficiently so that the seed used in overseeding can make good contact with the soil for good germination.

 

Burning a berumudagrass hayfield primarily for weed control at the Batesville Station of the University of Arksansas.
Photo courtesy of the University of Arkansas Cooperative Extension (http://batesvillestation.uark.edu/3_.jpg)

Many years ago common bermudagrass would be burned in the winter to get rid of the dead surface grass and in the process any thatch accumulation. It is still recommended that bermudagrass hayfields be burned for numerous reasons including thatch removal and reduction of insects and diseases.

Years ago bermudagrass lawns were also burned in the rural areas of Nevada and probably still are in some places. This is smart for several reasons that I will not get into here. We didn’t have thatch when bermudagrass was burned in the winter. Because we cannot burn dead grass any  more due to local ordinances and safety issues, this dead grass remains and adds to the thatch layer.

Dethatcher, vertical mower or verticutter. It can be used for several things but commonly used to remove thatch from
thatchy lawns or turfgrass areas. Bermudagrass can be a heavy thatch producer.

We now substitute a gasoline-driven machine (called a dethatcher, vertical mower or verticutter depending on who you are talking to) instead of burning the dead grass. This of course uses petroleum, adds pollutants to the air and leaves this bermudagrass thatch that we have harvested for dumping somewhere. Or burning. Aren't we smart?

Lots of Variabilities in Garlic Size Could be Due to Many Things

Q. My last load of mushroom compost with chicken poop had redwood chips in the load.  The guy who delivered it didn't clean his truck bed before hauling over my load of compost.  So, I've no idea if this contributed to the smaller garlic bulbs OR if i did something wrong OR if was the early 90 degree weather W/ the cold/freeze snap we had 4 times this spring. Spacing was 4"/6" apart in a  triangle grid; the other bed was 6"/6". I used a tape measure to mark off the beds.

The garlic was screaming to be pulled; some of the bulbs had already begun to split. The Polish White (no photo) usually grows medium bulbs; I have small and extra small bulbs.  Just a few with normal size. Since the size of the bulbs was consistently inconsistent in both beds, I bet you anything it was the compost.  I found out much too late that the 'organic' fertilizer store I used was not the correct place.  There are two in town.  One with high quality compost (I used it the year before.  Last years harvest was exceptional), and the other with inferior compost (I used this year by accident).  Live and learn.

Oh, and when I was prepping the beds, I forgot to use the blood meal.  May have been better that I forgot.  I have others tell me they've gone out and found their beds torn from animals smelling the blood.  We have all sorts of wild life out here.



Readers garlic. Good quality but some irregularities in size. This can be caused by many things.
 

A. This was a question submitted from Texas. Okay. Here's the deal on size of garlic. Planting larger cloves results in larger bulbs. Use the smaller ones for cooking or drying.

                       Spacing. They should be no closer than 4 inches apart if you are pushing size. I use drip tape and I plant on either side of the drip tape in triangular spacing to give them more room.

                       Bulb size is diminished with salinity. If your chicken manure was pretty hot or the compost was somewhat saline expect smaller bulb sizes.

                       C:N ratio. If the carbon to nitrogen ratio (amount of nitrogen in the compost) is too high it will diminish bulb size. Ideal C:N ratio is around 20:1. If it gets above 40:1 you have to supplement with additional nitrogen.

                       Harvested too early. I couldn't tell from the pic but what told you to harvest the garlic? What are the indicators you use to harvest? The bulbs look a bit young but what I could see of the tops there appeared to be some dieback. In northern California they let the tops fall over. We can't do that in Nevada but harvest when about 1/3 of the foliage is brown which is early for other places.

                       Not enough phosphorus in the bed. Did you apply phosphorus at the time of planting? I supplement with nitrogen through the growing season by sidedressing with my favorite N fertilizer. If organic you can use blood meal or guano or fish emulsion. If not organic then sidedress with ammonium sulfate.

                       You should know the quality of your compost. They should provide a copy of the test results. Usual problems with compost are salts too high, C:N ratio wrong or too high, high concentrations of toxic minerals such as boron, compost unfinished and needs time to finish. It should not be hot in temperature when delivered. Compost is finished when it has cooled down and the microorganisms have begun to die off.

                       A little bit of redwood shouldn't hurt. However, it does have a stunting affect. We see this in redwood beds when flowers are grown close to the boards.

                       Remember to supplement the planting hole with phosphorus...bone meal...not blood meal. Then sidedress with nitrogen every 30 days. Others will say not to sidedress. Try both. Apply nitrogen (blood meal or equivalent) every 30 days along the row a few inches from the bulb on half the plantings. Liquid would be better such as compost tea if you are organic. If animals are a problem maybe use compost tea applications.

 

Lots of Nutrients are in the Soil and Water But Sometimes the Plants Can't Get to Them

Q. Are there any micronutrients in our hard Vegas water of significant quantity?   I ask because I'm wondering if say a fertilizer I use lacks a certain nutrient (say calcium), could it be made up for through regular waterings alone (assuming we remove soil from the equation and all things being equal)? Can we definitively conclude our water is calcium-rich or sulphur-rich or whatever rich?

 

A. Micronutrients are kind of a funny thing to try and predict. Yes, there are lots of many nutrients (micronutrients as well as major nutrients) present in our soils and water as well as calcium, magnesium and other major or macro elements but not a sizable amount of nitrogen, hopefully.

This chart shows the effect of how acid or alkaline soil water is on 12 nutrients available for plants through their roots.
Take iron in the center of the chart, for instance. The grey bar that iron resides in is wider on the left side and becomes
narrower as we follow the bar from left to right. The wide part of the band means there is plenty of iron available to the plant. As the band decreases in size, its availability to plants decreases as well. Also notice that the pH scale on the
 bottom increases from left to right. From this we can conclude that as the pH increases (becomes more alkaline) the amount of iron that the plant can get from the soil is smaller. Even though the total AMOUNT of iron is unchanged, what the plant
can get from the soil decreases as the soil (or water) becomes more alkaline. This breakeven point for the plant varies
but is basically a problem starting around a pH of 7.5. If we know the pH of a soil or water, we can get a rough idea
which nutrients, in general, will be a problem for plants or not.

 

Just because the micronutrients are present does not mean they will do the plant much good. They must be in a form available to the plant to use. Micronutrient (and major nutrients as well) availability to the plants depend on how alkaline or acidic the water is (pH) as well as what is called the oxidation/reduction (redox) potential of the water. As alkalinity rises (pH increases) the availability of iron, manganese and zinc become more limited. So in our soils, not just in our water, the alkalinity affects whether the plant can take up these micronutrients.

The quantity of iron in many of our soils is more than adequate for plants BUT because the soil is alkaline the plant can’t use them efficiently. By making the water or soil more acidic these micronutrients convert to a more available form and the plant can take them up. Thus we have those iron fertilizers that are mixed with sulfur to help make the soil more acidic (e.g., Ironite) and we have chelates which bind the iron in an a form available to plants and release it in this form so the plant can take it up and use it (EDDHA, EDTA, DTPA). Unlike Ironite, for instance, the chelates do not affect the acidity of the soil making the iron (or any of the other micronutrients) more available to plants.

Ironite is a product that combines sulfur and iron in a single application.
The reasoning is that the sulfur will lower the soil pH as it is "consumed"
by soil microorganisms. This lowering of the soil pH will then make
the iron residing in the soil close to it, more avaible to the plant.

Sprint 138 is an iron chelate. Chelates work on the priniciple
that this chemical "claw" protects the iron from chemical reactions
and allows the iron to be used by the plant. The chelate is EDDHA.
The chelate is then called Iron EDDHA or FeEDDHA.

Those are the two methods used to make micronutrients available to plants;

1. increase acidity, or
2. chelate (protect) the nutrient in a form available to plants.

So are the micronutrients in adequate supply in our water? No, but they are in high enough quantities in MOST soils in the valley to satisfy most plant requirements IF the soil were more acidic. So we end up applying a liquid calcium (usually calcium chloride) to the fruit in multiple sprays (usually five or more) as the fruit is developing to alleviate corky spot and bitter pit in a highly productive orchard. But our soil is LOADED with calcium and you would think…no… that’s impossible, it should never happen.

Just because there is a lot of something in the soil or water does not mean the plant can get to it. Sometimes, besides the pH being a problem, these nutrients may be “bound up” either as secondary minerals (calcium in the form of calcium carbonate = limestone).

Calcium carbonate does not dissolve quickly. So if crops have a high demand for calcium over a fairly short period of time (March through August) they may not be able to get enough of that mineral (calcium) from the bound form (calcium carbonate or limestone). For instance, on some cultivars of pears and apples their demand for calcium can be very high over a relatively short period of time during development and the soil cannot release enough calcium to keep up with this large and quick demand. Thus the plants become calcium deficient (from this deficiency we develop disorders like cork spot on pear and bitter pit on apple; they are the same problem, a lack of calcium, but given different names on different crops).

Bitter pit in Mutsu apple grown in the Las Vegas valley.  Even though it looks like a "cork spot" which is the name
given to this disorder in pears. The brown spot may "erupt" on the surface as a blemish like this and/or it may also
cause discoloration of the white flesh under the skin. Sometimes it does not appear until after harvest.

This is cork spot on Comice pear. Notice the green "dimples" on the outside of the skin. Also notice the brown discoloration just under the skin and reaching into the fruit. Both corky spot and bitter pit are due to a lack of available
calcium from our calcium rich desert soils of southern Nevada. Calcium sprays (in our case using calcium chloride)
sprayed on the fruit during development helps to alleviate these problems.

 

Golf course superintendents see this problem too in our arid West. These very expensive golf course greens and tees are built totally on sand. The grasses on these spots sometimes develop calcium deficiency even though the water contains LOTS of calcium but the sand may not. They must apply calcium to their greens and tees even though the soil surrounding the greens and tees and the water they are applying is saturated in calcium in bound up forms. Because they cannot return the clippings to these spots (interferes with play) the nutrients are carted off these areas and dumped after mowing. If they could return the clippings and let them decompose back into the grass it would lessen the problem.

If turfgrass clippings are removed from the lawn area, this does not allow the nutrients to be recycled into the lawn area.
Mulching mowers are used to cut up the clippings into tiny pieces so that they decompose rapidly and release the
nutrients back to the soil where they were in the first place.

 

So a long winded answer to your question. Yes, there are lots of these nutrients around but often times they are unavailable due to the chemistry of the water, the soil and interactions with the plants.

 

Can I Prune My Shoestring Acacia Now?

Q. I planted a shoestring last Spring, and it is doing well. It has five lower limbs off of the main trunk and one of them is all most as long as the tree is tall. I was wondering if I can cut them off this Fall? They are so low they will be removed eventually any way. If I remove them will it help the main trunk to grow faster? Will it hurt the tree to cut them off now?

A. There are several things you can do about this. You will not hurt the tree to remove a few limbs (particularly lower ones) now. When I went to school and studied arboriculture, my professor would say two things I will never forget; the best time to prune is when the pruners are sharp AND if you know how to prune, you can prune using only your thumbnail. I have always strived in learning how to prune, what he meant by that. As time passed, I slowly learned.

 

In the desert we have to be a bit more careful in pruning because our environment is so harsh but the principles he taught me are still valid.

            Remove tree limbs very close to the trunk, making the cut with a sharp, clean and preferably sterilized pruning shears. Make the cut leaving a tiny bump (called the shoulder) intact on the trunk. Don’t cut flush to the tree trunk.

The shoulder of a limb attached to the trunk and where to make the cut in relation to the shoulder.

            Let me explain better where to cut. If you look at the limb, where it attaches to the trunk, you will see that it flare (become wider) at its base, at a point where it attaches to the trunk. Cut with the smallest cut possible but as close to this flair as you can. Do not leave a stub. Leaving this flair intact on the tree trunk is NOT leaving a stub.This type of cut, not cutting into the flair, will heal much faster than if you cut or remove the flair. You do not need pruning paint.

            If limbs are too long, yes, go ahead and cut them back now. Not a problem. You just do not want to make major cuts that change the basic structure of the tree now which opens it up to sunlight that might damage the limbs and trunk through sunburn.

            The fewer side branches or limbs you have (within reason), the faster the tree will grow in height. So remove smaller, weaker limbs or branches at the trunk. You can do that now as well.

 

Update on Grape Leaf Skeletonizer from Reader

I big thanks to Powell Gammill from Phoenix, Arizona, for sending these pictures along with his comments on grape leaf skeletonizers.

Attached are two pics I took last year that capture a female laying eggs (note precise characteristic pattern)

Grape leaf skeletonizer laying eggs on the grape leaf surface.
Picture courtesy Powell Gammill.

and a pic of newly hatched 1st instar larvae (and one 2nd stage) in uncharacteristic (non-line) feeding pattern (which I hope may indicate a viral infection is established around my vines) and a couple of organized egg clusters.  You can reprint them if you wish.

Grape leaf skeletonizer eggs laid (right bottom) with larvae hatching from eggs at center, bottom.
Photo courtesy Powell Gammill.

In addition to the Btk and spinosad, you can use dormant oil before leafing and horticultural oil to try and kill the molting larvae under the vines (but this would kill any emerging parasitic wasps as well).  By rotating treatments you can hopefully prevent resistance.  I have found a easy method of reduction is to look under the leaves and remove any infested leaves before they hatch or get large enough to move on.  They strip a leaf at a time and are not too hard to spot if they are still young and on a leaf.  Also the adults can't fly very well and look inelegant in flight.

Grape leaf skeletonizer adults.
Photo courtesy Powell Gammill.

As you said, if you pick the 3rd and 4th instars off manually do so with gloves and remove them as if you just drop them unharmed they may either find their way back to a vine or go to ground and cocoon. 

I think these were drying out getting ready to start flying.  Note, ours (Phoenix, AZ) have an orange head.  They too are reportedly irritating (cyanide?) to the skin...I know the larvae have irritating bristles.

Beautiful Moth Now, Deadly Assignment in Your Garden

I was working in the garage the other night, cleaning out some things and holding a small box. The overhead light was on so I could see the small box in front of me. Startling me, this flew in and landed on the box, attracted to the light.

Of course this is not my picture but can be found at

http://www.fs.fed.us/wildflowers/pollinators/pollinator-of-the-month/images/hawkmoths/eumorpha_typhon_lg.jpg This is the sphinx moth, hawk moth or sometimes we call them the hummingbird moth because they can pause in mid-air in front of a flower and sip up its nectar. However, my moth was gone as soon as I tried to get my camera. But the feds site will let me use their picture.

You will see them flying now, usually around dusk although they feed on the nectar of flowers and serve as very good pollinators, particularly of flowers with very long "throats". This is because their "tongue" is so long. But....there is a problem for gardeners.

This is the hornworm and it is the larva or immature (baby) of the sphinx/hawk/hummingbird moth. You will see them devouring grape leaves (one of their favorites), tomato leaves and other garden crops. They can be devastating this time of year and you might see them again in the fall.

 

It is your call but if  you want to control these "caterpillars" or larvae then use Bt (Dipel or Thuricide) or Spinosad for organic control. It will not harm the adult moth but will help in controlling the eating by the larvae. This will of course prevent the larvae that you kill from becoming more moths.

Watch for Grape Leaves Disappearing - Skeletonizer Flying

Q. I just sited my first grape leaf skeletonizer moth. I’ve learned that Bt will control the worms.   I’d like to try and minimize the larvae if I can by eradicating as many moths as possible. Can you recommend the best course of action, if any, to control the moth itself?

Grape leaf skeletonizer adult moth

A. Not a lot of people know what they look like. They are a dark, blue-black moth that resembles a wasp more than a moth. I will post a picture of the moth, eggs and damage on my blog for all to see. If you have grapes, everyone should start looking for these guys.

Grape leaf skeletonizer larva feeding ont he underside of grape leaf. This picture courtesy University of Arizona
and can be found at http://cals.arizona.edu/yavapai/diagnostics/Assets/Images/Insects/grapeleafskeletonizer1.jpg

            The adult only lives for about three days. Pretty much its sole purpose is to reproduce. The damage comes from the larvae eating the leaves, not the moth eating the leaves. The eggs are laid on the bottom of the leaf. The life cycle of the insect is about 60 days (two months). It takes about 7 days for the larvae to hatch from the deposited eggs.

            I know you want to control the adult in an attempt to control the young but it probably is not the best approach since the adult will be hard to kill. Soap and water or insecticidal soap will work IF the soapy water comes in direct contact with the moth. But since the adult does not eat the leaves, you would have to actually spray the adults to kill them.

            The larvae are fairly easy to kill since they eat grape leaves. You must spray it on the bottom of the leaves. Do this by pointing your applicator so it sprays up, on the bottom of the leaves. The Bt (Dipel, Thuricide) has about a one week residue on the leaves.

            Spinosad will also work and has about the same staying power but is a little harder on bees.

 

A word of caution: These larva are nasty critters. If a larva falls on your skin it will feel like you were burned by a matchhead.

Pruning Fruit Trees at Planting

Q. I planted some barefoot fruit trees earlier this year and unfortunately several did not survive. This was my fault since I didn't get them planted right away and the roots may have dried out.  I want to replace them with container nursery stock. The problem is that I want to prune the trees to knee to height per your ladderless orchard recommendations. All the nursery stock trees have limbs well above this height.  If purchased and planted now, can these trees be cut back to the lower height when planted and survive?

 

A. They can be pruned back provided the stems are not too large in diameter. Pick smaller container plants that are in good health. They will catch up or even surpass the size of larger container stock.

            I would make sure that the stem or trunk is well under an inch in diameter so you can cut them back. This should produce several new stems about 8 to ten inches below your cut.

            Some fruit trees sucker better than others. Peach and nectarine, for instance, have a harder time sending new shoots up after they have been cut if the diameter is too large. You should not kill the tree if you do this provided the diameter is small.