Xtremehorticulture

Xtremehorticulture of the Desert

Grape Bunch Disease Need Applications of Fungicides in the Spring

Leave a Comment / botrytis, bunch rot, control, grapes, mildew /

Q. I am a big fan of your RJ newspaper column, but I haven’t seen any answers about what’s happening to my grapes. Please advise. This the stuff isn’t on all my grapes. I have four plants and maybe 10-15% have this white stuff on certain bunches. This is from the reader and I would call it a “bunch rot” a bunch disease that must be controlled in the spring, according to the fungicide label. Most homeowners use a “copper based fungicide for control. A. It’s a disease of the bunches; a “bunch disease”. I thought this might happen mostly because of our wet spring. Bayer tells us, when treating for grape bunch diseases, that about half of the improvement is due to better air circulation and the other half using a copper-based fungicide. They are right! Collectively, both downy and powdery mildew are called “bunch diseases”. The fungicide must be applied right after a rain or during high humidity days just after it flowers. Grapes flower in mid March in Las Vegas. One of the bunch diseases later in the summer (about May) from about three or four years prior. To late for the first application of most fungicides but give it a try.             This looks like one of the grape diseases, probably grape downy mildew. Try removing bunches and leaves so that you have one bunch every foot. If it is tight with leaves, remove some of the leaves as well to improve air circulation. Don’t remove too many leaves so that you get direct sunlight on the grapes or limbs. You want to improve the air circulation around the bunches and the berries but without putting the bunches (and limbs) in direct strong sunlight for any length of time in the desert. One of the grape bunch diseases from a few years ago in Las Vegas.             You can apply a spray mixture of a copper-based fungicide according to the label. Liqui-Cop and Bordeaux sprays come to mind, but any copper-based fungicide (a fungicide that includes copper in the ingredients) should work. You may have to repeat the application. Read the label.  Warning. Grapes must be on the label of a fungicide because of testing and recommendations concerning the rate of application. One of the many copper-based fungicides. Check the label to make sure your crop and rates are mentioned.             Remember fungicides help prevent plant diseases but do not “cure” the plant of a particular disease. You are spraying early to prevent the spread of a bunch disease. There is some evidence that Neem oil has given some protection, but copper-based fungicides are better. Grape leaf removal around grape bunches to improve the air circulation.             You may be too late with a spray of any kind, but it is worth a try. Do it very soon and follow label directions for controlling these “bunch diseases” on grapes. Next time apply your favorite spray earlier in the season, right after rain or during high humidity, to prevent the spread of “bunch diseases”.

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Nutrgrass in Lawns Good Riddance!

Leave a Comment / bermudagrass lawn, control, nutgrass, nutsedge /

Q. We have had nutgrass in our lawn (Tiff type Bermuda) for many years. There used to be a solution that would kill it or keep it at bay.  I haven’t seen it for the last 3 plus years.  It seems unless we can pull out the root and little “nut” at the end, it just keeps spreading. Any suggestions? Nutgrass in a Tiff-type bermudagrass A. Used to be that nutgrass, also called nutsedge both the purple and yellow types, were common problems in nursery soils. Once established in landscapes they were both tough to get under control because of the “nut” you mentioned. If the top was killed, the nut would regrow new “blades of grass”. The top, which looked like a lawn grass at first glance, would grow faster than the surrounding grass, or a light green color, and became a problem in well-manicured lawns or other stands of grass. Nutgrass with an attached “nut” which oftentimes breaks from the mother plant when it is pulled. Leaving behind the “nut” is the most common way for this weed to spread.             The best chemical control is with a product containing “Halosulfuron-methyl”. Look for this in the ingredients of the product. It may be called a trade name like “Sedgehammer” or others. That’s why its important to read the ingredients of a chemical and not just the trade or product name. This product may be hard to find so it may require buying it online from Do My Own pest control.             It will require more than one application to kill the “nut”. The top will die, and you think it is dead, but the nut may regrow new “blades of grass” in a few weeks so watch for it. It is important to follow the label directions for these products exactly. In the past the problem has been the resprouting of the nut after the top died. It is very important to reapply this chemical as soon as regrowth is seen, or the spreading of the nuts will make the problem worse.             The hybrid bermudagrasses are a good choice for lawns in our area. They can use about 25% less water than tall fescues lawns and typically have few weed or disease problems. Just for your information, the “Tiff-type” hybrid bermudagrasses come in different varieties such as ‘Tifdwarf’, ‘Tifgreen’, ‘Tifway’, and others. Tiff type bermudagrasses are used on golf courses and isn’t the same grass as our weed, Common bermudagrass.

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Olive Tree Suckers Easily from Many Locations

Leave a Comment / control, olive, Suckers /

Q. An olive tree on the property of our homeowner association is sending up suckers from its base and along the trunk. I am thinking it’s because the tree is not getting enough water. Our landscaper continues to remove them and thinks otherwise. Who is right? A. Suckering from the base can be a sign of a lack of water in some trees but olive trees also sucker from the base and along the trunk easily. If you look at the base of older olive trees you will see some “knots” or swellings attached to the lower trunk, trunk limbs and root flares as they get older. There can be so many of them the tree becomes disfigured. It gives olive trees a great deal of character in their old age. Olives sucker easily from clusters of immature or unopened buds hidden on the trunk. You can spot them as bumps or gnarls. A limb was removed from this olive tree which encouraged the suckers to grow.             These swellings along the trunk and limbs develop from clusters of immature buds embedded in woody growth. Suckers can originate from these “knots”. These knots or “burls” can get quite massive in older trees.             Burls are common in other trees as well particularly trees that are prone to damage from fire or animals like coastal redwoods. Burls are valued by many woodworkers but despised by the construction lumber people.             Suckering from the base of some trees, however, can be in response to drought. There may or may not be obvious swellings at the base of these trees. The tree finds it difficult to deliver water to its top when water is scarce. This tree rose suckered from the rootstock after the top of the tree, or scion, died back.             These clusters of undeveloped buds, previously asleep, begin growing from the base. Some are scattered through the wood and others are in clusters. Growth from the bottom is easier to support when water is scarce then growth at the top.             Some trees like many ash trees don’t have that survival mechanism. When water is scarce, their leaves begin to scorch, push very little new growth and limbs dieback particularly during hot weather.                     You could still be right. The tree may not be getting enough water and that just makes suckering even worse. It’s best to look at the tops of the trees to make a drought determination. When water is scarce, the canopy growth suffers and when water is really restricted there is leaf scorch and dieback by the tallest limbs.                       If the tree is growing nicely and has lots of leaves then I would say it’s getting enough water. The suckering at the base of the tree is probably normal. However, if the tree is sparse in its canopy and growth is poor and it is suckering from the base then I would worry about enough water.

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Sapsucker Damage on Australian Bottle Tree

Leave a Comment / control, damage, ornamental trees, sapsucker, woodpecker /

Q. I have a 5 year old Australian bottle tree that has a large canopy.  The canopy has very yellow leaves and I have found on  the trunk  about ¼ inch holes in the trunk. There are quite a few holes but I have not counted all of them. I don’t want to lose my tree. Can you tell me what is wrong with it?  No picture was submitted of the tree damage. A. This is probably sapsucker damage. They are in the family of woodpeckers.They are migratory in the Las Vegas Valley and probably overwinter mostly in northern Mexico. So you see this kind of damage on preferred trees twice a year. https://www.uaex.edu/publications/pdf/FSA-7561.pdf Sapsucker damage on Tipu. Sapsucker damage to Southern Live Oak Sapsucker damage to blue ghost eucalyptus For more information and some suggested control measures visit my blog at these locations. http://xtremehorticulture.blogspot.com/2011/08/someones-drilling-holes-in-my-trees.html http://xtremehorticulture.blogspot.com/2015/12/holes-in-trees.html

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Sap Coming From Peach Trunk to Top of Limbs

Leave a Comment / borers, control, peach sap, sunburn /

Q. Our peach tree has sap coming out from the ground level to the top of one of the limbs. Not sure if too much water, not enough water, too many bugs or what. A. This is the time of year we start noticing borer damage in peach trees. Sap comes out from the limbs and possibly all along the trunk. Branch dieback due to peach borer damage. A clear indicator of borer damage will be that the bark around the sappy areas will peel off, leaving bare wood under it with clear feeding damage (looks like someone took a miniature sander to the wood with no clear pattern) and if you pull enough bark away you will see flattened, oval exit holes from the adult beetles. Bark peeling away from dying branch due to borers. You may even see some sawdust under the bark in these “sanded” areas from their feeding. Remove all loose bark all the way into good wood. You may even find a flattened, ugly larva of a borer just under the bark still feeding. Keep it for a pet if you want to. Borer in removed dead branch If damage is more than 50% around the limb, cut it off. Do not paint with black tree wound paint. Paint the trunk and remaining limbs with diluted white latex paint (50/50 with water) on the upper surface of all branches down to one inch in diameter and the trunk. Borers like limbs and trunks exposed to the hot and intense sunlight. White paint keeps limbs and trunks several degrees cooler than brown limbs and trunks and helps to reduce damage to these parts by intense sunlight. 

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Slugs Can Cause Early Plant Damage to Lettuce

Leave a Comment / control, holes in leaves, lettuce, slug damage, snail damage /

While in Kosovo recently a farmer complained about the lower leaves of his young lettuce plants were damaged, wilting and not looking very good. Spring is not lettuce weather in the hot desert but in cooler climates it is. Early lettuce with drip tape and plastic mulch for weed prevention. Young lettuce transplants put out in the field had lower leaves that were damaged. Feeding damage from slugs that turned brown could be seen on the base of the leaf toward the bottom of the picture. Small slugs could even be found at the base of the leaves.  Feeding damage opens wounds in the surface of the leaves and allows pathogens to attack the weakened leaf itself. Slugs and snails are active at night. Slugs can be trapped between rows that are bare soil by laying down cardboard or newspaper and collecting snails and slugs that move there to avoid daylight. It is always a good idea to remove the bottom leaves of plants growing from a stem which will lessen pest problems and improve your chances of getting better spray coverage. This includes vegetables like cabbage, tomatoes, peppers, summer squash and eggplant. Lower leaves of tomato were removed to improve air circulation and reduce disease problems. Leaves at the bottom of the plant are frequently shaded and do not contribute much to the rest of the plant and may actually be a detriment. Removing leaves also helps in getting better spray coverage and insect control.

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Dark Brown or Black Shells on Oleander May Be Scale Insects

2 Comments / ants, brown apricot scale, control, insecticide, lecanium scale, oleander sticky, scale, sugar /

Q. I have a serious infestation of hard shelled black insects on my oleanders. I have a tree-like hedge of oleanders on both sides of my home. One of the oleanders is heavily infested but the problem is spreading rapidly to all the others. When I discovered the problem this weekend the oleander was black with thick black shelled insects about the size of an apple seed with sticky honeydew dripping down the trunk and stems. My neighbor thought they were black aphids so I power sprayed the oleanders with water and used a soapy water rinse. Unfortunately, the bugs seem to be adhered and need to be picked off. They are not on the leaves but are on the stems and trunks and climb higher than I can reach. I am attaching photos and would appreciate any advice you can give me. Will the 100o+ weather kill them? I removed the most heavily infested branches but that barely made a dent in the insect population so I wonder if I have to remove the whole oleander tree. A. This is one of the many scale insects. Scale insects are not terribly common in southern Nevada. They are difficult to control because the insect is living under a protective “shell” it created.             Because the insect does not move around once it creates its “shell” they don’t attract attention. Frequently they come to our attention because of the sticky sap they excrete is shiny and attracts ants.             Oftentimes the question becomes how can I control ants, not realizing the ants are there because of other insects like scale and aphids. The ants can move the scale insects around so it is best to control them as well.             If you don’t have very many of them you can treat each scale with alcohol and a cotton swab. But usually there are too many.             The usual recommendations for controlling scale insects is to either spray a horticultural oil on top of them in early spring to suffocate them or use a conventional insecticidal spray. a conventional insecticide when the insect is no longer protected by its hard outer covering, the scale itself. Never spray an oil when a plant is in bloom. Usually two winter or early spring applications are called for. One of the many horticultural oils for suffocating insects. Particularly good on soft-bodied insects like aphids, mites and the like but they will also kill beneficial insects so use it where and when it is needed and not indiscriminately. These insects are not hard to kill when they are not under those shells. The females release young scale insects without the scale (called crawlers) around May. It is at this time the insects are most vulnerable. It is also the time when it starts getting hot and the spraying oils in the heat is not recommended. I have done it very early in the morning with no problems to the trees but you must do it early in the morning. When in doubt, spray a small area of the plant first and wait 48 hours to see if the plant reacts negatively to it. If it doesn’t, go ahead and spray in the summer as well but do it in the cool morning hours right after sunrise.

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Controlling Bermudagrass Growing in…..

Leave a Comment / bermudagrass, control, devil grass, devilgrass, herbicides /

Common bermudagrass stolons creeping from the lawn over a sidewalk. Hybrid bermudagrass is much more restrained in its growth. This is a queston frequently asked, “How do I control bermudagrass in……” so let’s talk about it. The big problem is common bermudagrass. It is spread by seed, underground stems called rhizomes that can grow under the surface of the soil for many feet and re-emerge in a new location. Sort of like “Whack-A-Mole”. You pull it or spray it here only for it to popup over there. Below ground the bermudagrass cannot get the energy it needs from sunlight. It must rely on food supplies sent by the mother plant growing in sunligh OR live off of stored food in its stems. It can also spread by planting, or accidentally planting, any of its stems above or below ground. For instance you can take the above ground growth, cut it up into small pieces, throw it on the ground, water it and it will start a new plant any place these cut up pieces fall. When we WANT it to spread like this, we call are planting by stolons or “stolonizing” the area. The hybrid bermudagrasses, the kind that are nice to grow like on golf courses, is planted exactly this way. The underground stems that spread the mother plant to a new location all by growing underground are called rhizomes. The only difference between the above ground stems (stolons) and the below ground stems (rhizomes) is there location AND their propensity to either grow above or below ground. What you can do to stolons, you can do with rhizomes essentially. So if you cut up a bunch of rhizomes the same way as stolons and spread them on the soil surface, guess what will happen. You got it. You have a new lawn whether you wanted it or not. Hybrid bermudagrass stolon (left) stem and leaves (right) and rhizome (bottom) Question for YOU. What will happen if you rototill a bermudagrass weed area in the hopes of getting rid of it? Answer: You spread it. So how do you get rid of bermudagrass weeds? You exhaust it. You kill it, let it grow a bit, kill it again, let it grow, kill it again, let it grow, kill it again…… In this way you begin to exhaust its stored food supply AND by constantly killing or cutting off its access to sunlight you deny it the ability to put more stored food into its food supply. In the end you exhaust it, weaken it and it dies. You can deny it sunlight by constantly killing top growth back as soon as it gets exposed to that life-giving light a week or so. You can kill the top growth by mechanically whacking it off to soil level or below or killing it to the ground with a poison such as Roundup or even vinegar. Anything that will cause it to die to the ground and not hurt the surrounding environment. The advantage of Roundup is that it is systemic and will travel into the ground a distance and kill somewhere below ground level. To grow back requires more energy and so it will be more effective than just whacking it off or killing the tops. The disadvantage is that it is a weed killer and it may have some adverse side effects. Other chemicals to look at include Poast and Fusilade which are also systemic weed killers and are potentially less damaging to surrounding plants. Nothing wrong with a hoe, shovel and other tools that will help take it to the ground. Regardless, the secret to success will be to stay on top of it and never let it grow back more than a few inches before you knock it down again.

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Strawberry Weevils A Big Problem When Growing Strawberries

Leave a Comment / control, insect eating strawberries, roly polys, sowbug, vine weevils /

Readers strawberry plant with damage Q. A friend of mine has recommended that I contact you regarding a problem I’ve got with a newly planted garden in my back yard.  These beetles are devouring my strawberries and I’m even seeing them on my other veggies in the same planting area.  I tried the water, soap, baking soda, cayenne pepper spray solution but it’s not seeming to make much of an impact, if any.  I really don’t want to use pesticides.  A. What you have is most likely one of the vine weevils. Because it is on strawberries I would like to think it is the strawberry vine weevil but there are other vine weevils as well. Regardless of the name the problem and controls are similar. Difficult. Vine weevil on readers plants, picture magnified and cropped             Probably one of the more effective ways is going to sterilize the soil. This can be done without chemicals. This will require you to remove the plants from their home, wash them thoroughly and replant them in soil that has been sterilized through solar sterilization. This is a bad time of year to do this however. You could do this this fall.             You will sterilize the soil by tilling or digging the soil so that it is loose to a depth of 12 inches. Water the soil. Place clear plastic over the top and seal the edges with soil and rocks so the wind does not blow it open.             Leave it covered so that the soil “cooks” for two hot days. After two hot days you can uncover it, let it cool and plant again with clean plants. Use clean mulch that is free of critters as much as possible.             There are baits you can buy but the bait must say it controls pill bugs and sow bugs , not just snails and slugs. The bed will get infested again and you will have to go through the same scenario to clean up the bed.             There are some insecticides you could use but check the label and make sure they can be used on fruit and see how many days you have to wait before you pick the fruit after you apply it. this is called the “re-entry period” sometimes on the label.

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Removing Bermudagrass for Desert Landscaping

Leave a Comment / common bermudagrass eradication, control, desert landscaping, removal /

Q. We are going to be removing about 3500 s.f. of bermuda grass. What is the best and easiest way to do this ? A. I am assuming this is common bermudagrass, not hybrid bermudagrass. Many of the hybrid bermudagrasses are more restrained in their growth and easier to remove and keep under control. Common bermudagrass is more wild or rank in its growth and more difficult to remove and get under control. The easiest way I feel would be to irrigate and lightly fertilize the bermudagrass and mow it a couple of times so it is growing well and healthy. Sod removed with sod cutter in prepartion for the installation of desert landscaping         You don’t want the Bermuda to enter into any kind of dormancy before you try to kill it and remove it. Once the bermudagrass is happy and growing well then you will try to kill it. The best time to remove it is in the fall when it is sending energy reserves into its roots and stolons. There is a net movement of stored energy in this direction in the fall. In the spring there is a net movement of materials towards leaf and shoot growth. You will not get the best control in the spring but it is what it is.         Like I said, get it happy and growing well and when you have a solid stand of grass which has been mowed then spray it with Roundup. Make sure that you use a spreader/sticker in the spray mix and follow the directions precisely. I would also use distilled water, not our tap water since it is quite alkaline. Some people have reported a better kill with Roundup if there is a small amount of nitrogen mixed with the solution. You can take a tablespoon of ammonium sulfate or urea per gallon and put it in the mix as well if you want to but it is not necessary in my opinion. It is important to get an even application of Roundup over the entire grassy area. You do this by spraying the Roundup in an East West pattern first and then spray the second time in North South pattern so that you get good coverage.         When you spray, you should be moving your spray applicator at a speed of about 3 ft./s over the area. Do not stop and give some areas a larger dose. You’re just wasting chemical. Keep the applicator moving at all times when your spraying. It is important to keep your spray applicator moving at the same speed across the area slightly overlapping the sprayed area each time you cover it. Let the grass dry for 10 minutes or so and repeat the application in the opposite direction. Do not irrigate for 24 hours after the application.         Give yourself about 10 days and you should see the grass beginning to decline. Roundup does not work quickly so do not expect to see dead grass the next morning. It won’t happen. Rent a sod cutter and cut the sod out as deeply as you can. Once the sod is removed begin irrigating the area heavily and frequently and apply a light application of fertilizer to try to stimulate any bermudagrass which is remaining.         You will probably see spots of bermudagrass trying to come back in seven days if it is hot outside. Spot spray these areas with the same Roundup solution as soon as you see them emerging. Stay on top of these spots and kill them as you see them. Do not let these get out of control. This is very important. I am not telling you to keep an old solution of Roundup. Every time you spray you need to mix up a new batch. These solutions are not stable very long and begin to disintegrate fairly quickly.         Once you feel you have most of the bermudagrass under control you can begin to develop your landscape. If you are putting in desert landscaping with rock mulch, the bermudagrass will reemerge where you have your drip emitters around the new plants. You can Spot spray this emerging bermudagrass with Roundup making sure none of the spray lands on desired plants. It is okay for it to land on the soil or rock but not on green leaves or stems of living plants.         Other chemicals you could use around shrubs and groundcover plants for bermudagrass control are Fusilade and Poast but they can be a little sketchy in their control. You can also grub new growth out with a hoe when you see it but do not let the grass go to seed or get very old or it will get established again. Bermudagrass will not grow in complete shade so making sure you  are shading the soil with rock, mulch or competitive groundcovers like turfgrass is good control. There is more information on Bermudgrass here. http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7453.html

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