Xtremehorticulture

Xtremehorticulture of the Desert

Elm Leaf Beetle on Siberian Elm, not a Chinese Elm

Leave a Comment / chinese elm, elm leaf beetle, leaf damage, Siberian elm, skeletonized /

Q. Looks like elm leaf beetle or leaf miner damage in the picture I sent. What to do? Let the tree flush a new set of leaves after the larval feeding frenzy? These are trees cared for by volunteers and found in Spring Mountain Park near Blue Diamond. I would rather have the volunteers not use any systemics. Any thoughts? This is elm leaf beetle damage to Siberian elm. To my knowledge the elm leaf beetle only attacks Siberian elm. Siberian elm is different from Chinese elm. A. That’s elm leaf beetle (ELB) damage on Siberian elm leaves. We used to see a lot of it when there were more Siberian elms in our community. If you can catch them in the larval stage, they are easy to control by spraying the leaves with any type of insecticide. Any insecticide works including soap and water and salt sprays. You just need to kill them. That’s elm leaf beetle damage taken from a slide over fifty years ago in Colorado.             The problem is the act of spraying which means specialized equipment because the trees can grow 40+ feet tall. Soap and water sprays kill on contact. They don’t have any residual, so you must spray the leaves until the level of control you want is achieved. Otherwise, you must use a systemic insecticide as a soil drench or have it absorbed through the tree trunk. Larvae of elm leaf beetle adults (don’t confuse them with adult cucumber beetles) taken from a slide over fifty years ago. They are ephemeral, meaning they last only a few weeks and they are gone. This is a nearly mature form of Chinese elm, maybe evergreen elm. Notice how tall Chinese elm can grow. Don’t confuse them with Siberian elm which is a trash tree.             I just ignore them and tell people not to plant Siberian elm when I see it. Recovery of this tree from single feeding by ELB is not a problem. I have only seen ELB eat the surface of Siberian elm leaves, not any of Chinese elm types including lacebark elm. Plus, ELB has only one generation each year while other insects, like the great leaf skeletonizer, is more destructive and mates multiple times each year.             I consider Siberian elm a “trash” tree and ranks about 2 out of 10 in desirability. Chinese elm, on the other hand, is a much better tree and I would give it an 8 or 9 out of ten. By the way, Siberian elm is no longer sold as a landscape tree. No great loss. Siberian elm removed with a telehandler…aka forklift… at Aherns

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Parts of Drip Irrigation System

Leave a Comment / arrows, closed loop, drip irrigation, flush, irrigation design, water pressure /

Q. When installing drip irrigation, what irrigation parts do I need? Drip irrigation must have a filter and a means to regulate the pressure, a pressure regulator. https://www.digcorp.com/wp-content/uploads/digcorp/DripZone-1.pdf accessed on August 1, 2023. A. Make sure there is some sort of filtration, a pressure regulator to lower water pressure, and a way to “flush” the irrigation lines of debris, algae, and bacteria. Many people forget the flush part because they are used to using city water which is very clean. Every drip irrigation system needs these parts. It makes no difference if the filter or pressure regulator is first but drip systems need lower pressure. It works either way (pressure regulator first then filter or vice versa) but the arrows of water flow are important. A flush valve can be as simple as a ball valve connected to the irrigation circuit but it must be buried so it can be found and used. https://www.landfx.com/docs/item/202-land-f-x-drip-irrigation-design-and-graphic-conventions.html accessed on August 1, 2023.             The flush valve (oftentimes just a ball valve or on and off valve) is placed farthest away from where water first enters the “system” and hidden from site but easily found and used. The “flushing operation” involves cleaning the filters as well as cleaning the lines of algae and bacteria with the flush valve.             Cant say how often to flush the lines but drip irrigation MUST have clean water to operate. Well water is a “dirtier” water than city water. Wells pick up sand and other sediment that needs regular and periodic flushing. Once you get into a “rhythm” for how often to flush (every other time you water or every fifth time you water??) it doesn’t change much. Just plan on it when you use well water. Hunter screen filter and pressure regulator in a bag.             Lower the water pressure with a pressure regulator. Water pressure from a municipality fluctuates depending on how close you are to the municipalities water pump or reservoir. A plastic pressure regulator helps lower the water pressure into the “normal range” to operate drip irrigation. The pressure of water from wells may vary. For most homeowners, the water pressure range for smaller drip systems is approximately 25 to 30 psi. For larger drip irrigation operations (half acre and above), water pressure of drip systems may need to be more than this. All PE tubing specifies its operating pressure and other important information such as emitter distance, size of the emitters, etc.             Water used in drip irrigation needs to be particle free. Clean it before it comes in the drip lines. Drip irrigation relies on small holes that can plug, to deliver water. Clean water requires filtration. Even though water from municipalities has been filtered, filtration is still needed for drip irrigation. Most commonly and inexpensively, screen filters (screens are 120 -130 “mesh”, which means 120 to 130 holes per each square inch) are used. The filter is added, usually after an irrigation valve. Pressure regulators must be used to protect the drip tubing from operating at too high of a pressure. If incoming pressure is to great or fluctuates, a more substantial pressure regulator (such as brass or more permanent type) should be used. Incoming water pressure should not exceed the PE or fitting operating pressure. Rainbird pressure regulators https://www.evergreen-irrigation.co.uk/product/rain-bird-water-pressure-regulator/             Regular flushing cleans the lines of debris, algae and bacteria. It is important to flush the lines every time repairs are made as well as regularly. Part of the “flushing operation” requires a separate “flush valve”. This is particularly true if using a fertilizer injector.             When designing drip irrigation, I prefer the “closed loop” type of irrigation system design. That’s where there is a header and footer that “close the loop”. Closed loops minimize the number of places where you have to flush and “evens-out” the water pressure of the system. It costs a bit more to install but the benefits are worth it in my opinion.

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Plant Roots Prefer Water and Nutrients Applied to the Same Place

Leave a Comment / drip irrigation, plants, roots, vegetables /

Q. I have read that plants grow better with water delivered to their roots, at the same spot, over and over again. Is this true? Eggplant growing with drip irrigation in a raised bed without sidewalls. A. Yes, it’s true but you probably won’t notice the difference. Why? Unless you compare plants growing with water applied to the same spot, over and over, with plants watered at different places you wont see much difference.              Plant roots get used to the amount of water and air when water is delivered to the same spots and depth, over and over. That is one reason why drip irrigation, along with the proper spacing of emitters, is so successful as long as the plant “wets its roots” to the appropriate depth each time. Watering with a hose will not as consistent.             Water should wet the roots to the same depth every time. Small shrubs need to wet their roots to a depth of 12 to 18 inches, medium sized trees and shrubs 18 to 24 inches deep, and tall trees or shrubs should have wetted roots to a depth of 36 inches deep. This water should be applied to at least half the area under the plant’s canopy. Obviously then large plants need more water applied to them, and this water applied to a larger area, than the smaller plants.

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Yellowing Container Cycad in the Summer

Leave a Comment / adding epsom salt, container plant, magnesium deficiency, pot plant /

Q. My cycad (sago palm) is yellow. I had read that it needs magnesium. What do you recommend? Sago palm (cycad) yellowing in container. A. Make sure the soil in your container drains and the plant is not watered too often. Repot or replant the sago palm when temperatures are cooler. Either wait or take it inside your house where it’s cooler when you replant and the plant reacclimates to the repotting in a week or so. Use a soil moisture meter when watering to make sure it’s not watered too often. Sometimes watering too often and poor container drainage of the soil can cause plant yellowing. Repotting sago palm (cycad) and watering as it gets hot helps cycad stay green.             Judging from your picture, your plant yellowing may be a fertilizer (plant nutrient) or watering/drainage problem. Iron shortages in plants are notorious for yellow foliage. Try applying an iron chelate to the soil when growth is first starting. Applying iron to the soil works if the plant is still growing. Once the plant stops growing then iron applications to the soil don’t work very well. There can be two reasons why nutrient deficiencies appear in soils of any kind; a shortage of a nutrient (you are suggesting a shortage of magnesium and you could be right) or the pH of the soil or its level of alkalinity. The reason I focus on iron so much is because a shortage of iron is very common to our soils and due to our tap water. Iron is probably the most common plant nutrient shortage due to our soil and tap water alkalinity. So try iron first. If that fails to “green the plant up” then try a different container soil (repot it with a different soil mix). This chart shows you the shortage of different plant nutrients with alkalinity (soil or water pH). https://extension.wvu.edu/natural-resources/soil-water/soil-testing/soil-test-nutrient-needs accessed on August 1, 2023. Putting sago palm in container in the correct landscape exposure can help.             After around June or July 1, iron applications must be sprayed on the new leaves and stems. In some cases, multiple spray applications a week apart are needed during that time. Before new growth starts in early spring, apply this same iron chelate mixed into the soil. It’s much easier. If in doubt, use an iron chelate containing EDDHA. Search for it online if you can’t find it. Magnesium deficiency, University of Florida,              Magnesium deficiency (which you suspected) is usually a speckling of leaves or fronds. It’s not usually yellowing. There is an abundance of magnesium in most of of our soils, but maybe not container soils. It is hit and miss. If you want to try magnesium (can be like whack-a-mole with plant nutrients), Epsom salts contain magnesium so apply 1 to 2 tablespoons of that mixed or the potting soil. Most plant nutrients won’t hurt the plant. Additions of boron is an exception so be very careful applying boron, chlorine or sodium. Higher levels of that can damage plants. (It is safer to repot with a different potting soil or, if that fails, put it in the ground.) After replanting, water the plant until water comes out of the bottom of the container. Even though sago palm or cycad is not a “palm”, lightly apply palm fertilizer to the soil once a year in the early spring.

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