insects – Xtremehorticulture

Cure Yellowing Eucalyptus Tree

Leave a Comment / borers, disease, EDDHA, insects, iron, water / xtremehorticulture

Q. I have a 20 plus year old eucalyptus tree. The leaves are very yellow. What is the cause of this? Its not a simple answer when it comes to yellowing eucalyptus. Could be anything. Judging from the plants around it and recent water restrictions I am wondering if it is water related. A. Yellowing leaves can mean many things. It could be a nutritional problem, watering issues, or damage from insects or disease. I need more information as well as leaf and tree pictures. Make sure it gets an iron application to the soil in the spring. To be on the safe side, apply an iron chelate such as EDDHA. This is the iron chelate called iron EDDHA. Because of its chemistry it performs well in all soil pH if applied in the spring. Check for a watering issue or a leak that floods the soil in that area. Eucalyptus is “mesic” in their water use so an application frequency for large trees should be used. When water is applied it should be deep and wide or large shrubs that receive water should be located under its canopy. Once a tree is chosen its increasing water use as it gets bigger has also been chosen.

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More “White Fuzzies” in Landscapes

3 Comments / cotton, disease, insects, white, wooly / xtremehorticulture

Q. I live in the central Las Vegas Valley and noticed a creep of linear white deposits on the stems of plants in my raised vegetable garden that has recurred in some desert-adapted plants elsewhere in the yard. It first appeared on sunflower stems, then lacinato kale, some basil, tomatoes and their stems, and now on new growth from a Vitex tree and turpentine bush. It seems to be spreading, in other words. Can you advise what this is, and any way to remedy it? A. Those “white deposits” are probably tiny “cocoons” of tiny insects in the landscape. I reorted these on my blog in previous years, calling them “white fuzzies”. I didn’t know what they exactly were either, but I knew that they were insect related. A horticulturist in the Phoenix area guessed that they were sharpshooter (insect) pupae, and he may be right. In any regard, these insect pupae “were just passing through” the landscape where they were “incidental” and probably not damaging these plants. Generally speaking, when we see white deposits on many different kinds of plants it’s usually not disease-related but may be related to insects. If guessed that these white deposits in this case are “insect related” then look at the plant and note any damage you might see. If there is no damage, then these insects are “incidental” to your plants. If you see insect damage to the plants, then they might not be “incidental” and it’s best to use your favorite least toxic insect spray and see if that stops the problem. Soap and water is usually a good first, least toxic spray and readily available. You can always try something more toxic as your second spray if that doesn’t stop the damage.

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Brown Spots in Lawn Probably “Frogeye” Disease

Leave a Comment / disease, Fusarium, grass, insects, irrigation, lawn, turfgrass / xtremehorticulture

Q. I have some large dead areas in my lawn. I don’t think it’s an insect problem. Watering is at 2 AM and 7 AM. This was my first lawn problem in 16 years! Unusual pattern for dead grass. Too random for irrigation I think. This picture you start to see the “frogeye” disease pattern. Looks like it could be a chemical spill. Here is where “frogeye” starts to make an impression. But its over. A. I looked at the pictures you sent, but the last picture was the most “telling” to me. I think your lawn had a disease problem that is now finished. Don’t do anything now! Let me tell you why I came to that conclusion. Insect problems here are not like those “rolling back like a carpet” problems described in books and online. Those descriptions apply to Kentucky bluegrass damaged by white grubs. We have grubs, but we don’t have much bluegrass anymore. Our lawns are 95% tall fescue and tall fescue reacts differently to insect damage. It pulls out like loose hair from an old animal skin. Plus, the pattern of dying grass does not resemble insect damage. Rolls Back Like a Carpet I first thought the brown spots were an irrigation problem, but the pattern doesn’t fit an irrigation problem. With irrigation problems, dead or damaged areas are in a pattern that relates to the location of sprinkler heads. I didn’t know where the sprinkler heads were, but the damage was irregular, so I ruled out irrigation. Irrigation problems are nearly always easy to see how they connect to the sprinklers. The pattern does, however, resemble a chemical spill flowing downhill and damaging the grass in its path. It was a possibility, but the last picture looked like advanced stages of a disease problem. We used to call this disease Fusarium blight or “frogeye”. This disease has since been renamed Necrotic Ring Spot. I thought “frogeye” was much more descriptive. Seldom will you see it this obvious but this is frogeye. See how it got its name? In advanced stages these dead areas can become one but you still look for little patches of green grass that would still be there. Sometimes its hard to see them. What led me in the direction toward disease were the small patches of green grass still alive but surrounded by dead grass. These small green patches of grass are how “frogeye”, now Necrotic Ring Spot, got its name. From the pictures, it looks like the disease has run its course and the grass that’s alive is healthy. I say this because the grass surrounding the dead areas appears healthy. This is the way lawn diseases usually work. They have a window of opportunity, when the weather is right for the disease to spread, and it takes off. The weather changes and the disease stops. You would be wasting your money to apply a fungicide now that it’s over. But, don’t disturb the brown, dead grass and leave it alone until fall. If you remove it now, it opens the soil to invasion by Bermudagrass. Bermudagrass loves sunshine, bare soil and water. It hates shade. Wait until the weather cools in late September or October, remove the dead grass and either seed or sod these areas.

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Spider Mite Problem from Nursery Tomato Transplants

Leave a Comment / disease, fruit trees, insects, nursery plants, transplants / xtremehorticulture

Q. Two years ago, you correctly diagnosed our tomato plants with spider mites from pictures we sent. Last year we got spider mites again. We started most of our tomatoes from seed last year but bought a few plants from a local nursery and planted them in each of the vegetable beds. Is it common to get spider mites from nursery plants? A. I don’t know how common it is for pests to be brought in from plant nurseries but I know it is more common than I would like. I have personally witnessed and identified disease and insect problems coming from nursery plants (houseplants, transplants, fruit trees and landscape container plants) before they were planted. Some disease problems on locally purchased container fruit trees. Sometimes insects and diseases can be problems when purchasing nursery materials. This disease infection may have started in the wholesale nursery first and passed on to the local consumer by the retail nursery.Avoid buying problem plants and introducing them into your home garden or landscape. Some plant problems are easy to see and others are not and don’t develop fully until later. Growing plants free of insect and disease problems requires knowledge about the pests, a clean growing area and a regular prevention and treatment program. Off-color leaves and spotting of leaves can be indicators that they are not healthy or they were poorly cared for. Purchasing nursery transplants can sometimes bring problems into the garden. It can be a problem when low prices are an expectation by the nursery or garden center which may encourage a lack of care or over application of pesticides by the greenhouse producer. Inspect your plants before purchasing and avoid buying those with problems at the get-go. If possible, put plants in isolated areas until you are sure they are “clean”. This is a common recommendation when buying houseplants. Houseplants are frequently loaded with disease and insect problems and infest other plants once inside the house. Fireblight disease was brought into this planting of apples and pears by introducing an infected Bartlett pear tree from a retail nursery. Once established, this disease spread to other European and Asian pears causing a lot of destruction and loss of plant life. When bringing home plants, spray them with oils and soap and water sprays before planting. Don’t bring home “bargain bin” or dumpster plants thinking you’ve got a deal. You are asking for trouble unless you know what you’re doing. Don’t risk contaminating pristine plants by mixing them with plants unknown to you.If you must do it, keep them isolated from other plants until you are sure they are healthy. As far as spider mites on tomatoes are concerned, inspect plants using the “white paper method” and a hand lens. Remove weeds growing in the containers, remove dying or damaged leaves, spray plants with soap sprays, and alternate with neem and other oils when you see them. Inspect plants

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Desert Green Presentation on Fruit Tree Pest Update for 2013

2 Comments / annual conference, bob morris, bugs, desert green conference, diseases, horticulture conference, insects, pests in fruit trees, what to spray, when to spray / xtremehorticulture

Fruit Tree Pest Update 2013 Notes for the PowerPoint presentation Robert Ll. Morris University of Nevada, Emeritus Desert Green is a conference held each year in Las Vegas for landscaping industry professionals. Here is a summary of my presentation on PowerPoint and my notes for my presentation. Slide 2.The UNCE Orchard was established in 1996 in North Las Vegas at UNLV’s Center for Urban Horticulture and Water Conservation. The center is located 100 yards east of the intersection of North Decatur and Horse Drive. Visiting hours are every Tuesday and Saturday morning from 8 AM until noon. Volunteers at the Orchard are welcome. The Orchard was established as a research and demonstration facility through Cooperative Extension. Slide 3. Fruit growing can be very successful in the desert because of our isolation from commercial orchards, our low humidity which helps to suppress diseases, and our high light intensities which helps to produce high levels of sugar in the fruit. Much of our plant material comes from Dave Wilson Nursery in northern California which produces high quality fruit trees for commercial orchards and nurseries. All of the fruit trees are planted by bare root, usually in late January or early February. We produce our own compost using local horse manure and green waste. The facility is a distribution center for wood mulch which is recycled urban green waste, primarily chipped trees removed from urban landscapes diverted from being buried at our local landfills. Our principal supplier of green waste is First Choice Tree Service, a Las Vegas based company. The management of the Orchard is focused on none or reduced pesticide applications, integrated pest management and ET-based irrigations. Slide 4. Whitewash reduces borer damage. We use whitewash painted to the outside of our trees to reduce sunburn damage. Sunburn damage to the trunk and limbs can attract boring insects such as the flatheaded Apple tree borer and the Pacific flatheaded borer which are problem insects in Las Vegas landscapes. By spraying the trunk and limbs with whitewash we can reduce the surface temperature of the trunk and tree limbs by five or 6°F. Whitewash is made by diluting white latex paint, or off-white latex paint, with an equal amount of water. In some cases more water can be used but the resulting whitewash should leave the trunk and limbs white in color. The most important sides of the trunk and limbs are West and South facing as well as the top sides of limbs. These areas receive the most direct and intense sunlight and usually show the most damage from boring insects. The whitewash will need to be re-sprayed or renewed every 3 to 4 years. Slide 5. Compost at planting enhances growth. This planting is nopal cactus which is used in Mexican culture as fresh vegetable, the fruit and animal fodder (feed). Once a pad is planted in good soil, harvesting of fresh vegetable from young pads can occur the following year. In three years, cactus fruits are ready to harvest. Cactus pads were planted in 2006 on the right side of the picture using compost applied to the soil after planting. The following year, 2007, pads were planted on the left side of the picture by this time the same amount of compost was mixed with the planting soil. Irrigations were every three weeks during the summer. Fertilizer applications were identical. Cactus pads that were planted with compost mixed in the soil exceeded the growth and production of cactus planted with compost applied to the surface only. In our desert soils it is very important to properly command soil at the time of planting for good growth, even of cactus. Slide 6. Staking equals faster establishment. It is important to stake newly planted trees to immobilize the roots so the tree can become established more quickly. If trees are not staked properly and the roots are not immobilized, movement of the plant due to wind can cause slower establishment. As trees begin to leaf out in the spring their canopy acts like a sail and can catch the wind causing the trunk to bend and possibly moving the root ball. Stakes should be driven into solid soil beneath the planting hole and not just the loose soil used for backfill. Trees should be tied to the stake so that the roots are immobilized but allowing the canopy and upper trunk to move. If the stake is not driven into solid soil, the root ball can move and root damage can occur with us slowing establishment. Slide 7. Wood mulch improves tree growth and health. Applying wood mulch to the soil surface has many benefits. Mulches help to keep the soil cool, moist, suppress weeds, improve soil quality, provide nutrients as it decomposes, fosters animal decomposers such as earthworms, lower soil pH and other benefits. Many plants in the landscape prefer to grow in improved soils rather than raw desert soil. Improved soils contribute to improved plant health. The best wood mulches come from a mixture of different types of trees. Bark mulch is pretty to look at but does not break down easily and contribute to the improvement of the soil and plants. Bark mulches easily blow in light winds and move in surface water. Wood mulch that has been chipped from trees does not blow easily in the wind and interlocks because of its rough surfaces. Wood mulches should be applied to a depth of 4 to 6 inches. These mulches should be kept away from the trunks of young trees, a distance of about 12 inches, until these trees are at least five years old. Wood mulches can be created from chipped landscape trees removed from local urban landscapes. When this wood has been chipped it will not contribute any disease or insect problems to landscapes where it is applied. Slide 8. Wood mulches were applied to fruit trees immediately after planting and the growth of these trees was compared to trees that did not receive any

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What Do I Do? My Lawn Has Dead Spots in Summer

Leave a Comment / brown spots, disease, insects, lawn, turfgrass / xtremehorticulture

This lawn is starting to recover. Just the dead spots remain. Wait until mid September or even October before you begin to remove dead grass. Leave it there for mulch to prevent weeds like bermudagrass from getting started. If you had dead areas develop in your lawn and you are pretty convinced the damage has passed then it is time to wait until fall to repair it. Three types of problems lead to dead spots in the lawn: insects, diseases and irrigation problems. It is pretty easy to determine if the problem has passed. If it has passed, the grass surrounding the damaged area and throughout the rest of the lawn area will appear healthy and rapidly growing. All that will remain of the damage are the brown spots surrounded by healthy, vibrant, green grass. Whatever you do, DON’T rake up the dead grass now and reseed or resod. Dead spots in a lawn are ugly. But what can be worse if you are not careful is to open up your lawn to a weed invasion, particularly bermudagrass, if you try to clean up these dead spots now. Wait. Wait until Fall, around mid September to mid October, to rake it up and reseed or resod. If you try to reseed it now you will fail. Even laying sod right now will be difficult to keep alive. But if you rake up that dead area and expose the bare soil to sunshine and irrigation, bermudagrass WILL seed itself right into those spots. And then you WILL have a problem. Leave the dead grass alone and let it “mulch” or cover the dead area, protecting it from invasion by bermudagrass.

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