Xtremehorticulture

Xtremehorticulture of the Desert

Wood Chips, Mexican Primrose and Bugs

Leave a Comment / bugs, Woodchips /

Q. I was overrun with Mexican primrose but have completed all my weeding.  I am thinking about putting wood chips around my roses to keep the weeds from returning.  Is this a good mulch for the roses? Or might it attract ants or insects I don’t want?  Mexican Primrose is a pretty ground covered the first year but it starts to get a little scraggly in the following years. It looks like it would be easy to control with weed killers. It’s not. A. Mexican primrose is very difficult to get rid of once it gets established. Many weed killers won’t touch it. An effective control technique is to keep removing the top of the plant as soon as it pops up. It takes lots of repetition and plenty of diligence but it works.             Remove the tops by cutting them back with a hoe. Some weed control chemicals “burn” it back and are essentially chemical “hoers”. The basic idea is to let the plant invest it’s energy into growing new, young tops and then remove the tops after they get only a couple of inches tall. This constant removal of the tops exhausts the energy supply stored in the roots and the plant eventually “gives up”. This is where bugs like to hang out in landscapes. They like water and irrigation boxes are where they can usually find plenty of it. The other thing they do is try to crawl into the house when it gets cold. A foundation spray of an effective insecticide applied in the fall when temperatures cool off and using that same spray in irrigation boxes usually keeps them at bay.             Woodchips are a great mulch for roses, combined with an application of compost on the soil surface underneath the woodchips. In my experience, the woodchips are no worse than rock mulch or gravel applied to the soil surface regarding attracting insects.             Insects like to “hang out” in irrigation boxes where there is water. Spraying the inside of the irrigation boxes with an appropriate pesticide every couple of months usually takes care of this problem.

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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 /

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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Insecticides Applied to Soil Not Good Idea Around Food Plants

Leave a Comment / bugs, control insects, fruit trees, lemon tree, systemic insecticides, whats eating leaves /

Q. Something is eating the leaves on my lemon tree. What can I use to prevent this? I found a product at the nursery and it says you can apply it to the soil to control bugs. A. If something is eating the leaves I would not be too concerned unless it is really eating a lot of leaves. We really have to be careful when we apply these types of poisons on the soil and around the food we eat.             If this insecticide is taken up through the roots and spread through the plant to kill a bug, we might also have small amounts in the fruit as well. The insecticide dissolves in water and moves down through the soil where it is absorbed by the roots. Once absorbed, it moves up through the plant providing protection from insects.             These types of products are called systemic insecticides and move into new growth after the application. The insecticide stays inside the plant and gives it protection from bugs. Rain or water cannot wash off this internal protection and you cannot wash it off by scrubbing the fruit.             There is an old saying, “The dose makes the poison.”  Insects, because they are small, require less of a poison to kill them than larger animals.  Even though insecticides have a label to tell you what you can or cannot apply it on, it does not mean that the product is entirely safe.             If you have to use an insecticide to control damaging insects, then I would recommend something that you spray on the outside of the plant rather than something which is taken up by the plants through its roots. In many cases, these insecticides which are sprayed on the plant will wash off or degrade in the environment.             It is up to you as the consumer whether you want to purchase this product and use it. As for me, I would not eat the fruit from a tree where an insecticide was applied to the soil and taken up by plant roots.

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July Todo: Pick up fallen fruit

Leave a Comment / bugs, infested, insects in fruit, July orchard todo /

Confused sap beetle, one of these varmints that gets into your ripe fruit. He or she is about 1/8 inch (3mm) long. Photo courtesy UC Davis IPM website. Pick up fallen fruit. Decomposing fruit, you could argue, is like composting… it adds nutrients back to the soil so why should I pick up fallen fruit? Well, how does fruit fallen from the tree decompose?           The insects that begin the decomposition process are some of the same insects which can attack the fruit on your tree. You leave your fallen fruit on the ground and these scavengers build communities out of the fallen fruit. Insects like the dried fruit beetle or confused sap beetle multiply their populations rapidly. In a couple of weeks this population of scavengers are looking for new food supplies. More information on these pests, click here.           The food supplies they find are the fruit on your trees and now you have a problem with tree ripened fruit – fug infested fruit.           You thought the birds were bad, at least you could cut around the bird-pecked areas. You can’t do that with fruit infested with these varmints. And watch out for your compost pile. If you add fruit to your compost pile, these varmints will invest the fruit there as well and spread to the fruit on your trees. Make sure fruit that is added to the compost pile is well covered and not exposed.

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