Xtremehorticulture

Xtremehorticulture of the Desert

Skeletonizers Still a Problem on Grape Even If You Spray

Leave a Comment / grape leaf skeletonizer, what is eating the leaves of my grapes, Why do I get skeletonizers when I spray /

Q. My grapevine has been overtaken by these worms/insects and at least 25% or more of the leaves have been eaten and/or turning brown. Are the grapes safe to eat?  I’ve attached some pics.  Early in the season I was spraying the vine with BT but maybe I didn’t apply it often enough?  Could the netting that I put over the vines have made it easier for them to multiply like they did?  I know it made it difficult for me to get to the undersides of a lot of the leaves, but it was that or feed the birds!  I think I will forgo the netting going forward now that the grapevine is more established. Midseason attack of grape leaves by grape leaf skeletonizer larva A. I don’t think the netting had anything to do with skeletonizer. The only thing I can think of is that birds might not have been able to get in to get the adult moths. They will not touch the larvae as they have stinging hairs near their heads which keep birds from eating them. There are probably five generations of these larvae in one season and they probably overlap on each other. The first one starts about April/Mayish and a new generation every 4 to 6 weeks so if you don’t spray at least three during the season you will miss a generation or two. The Bt spray only lasts a few days and it is gone. Control = picking the right poison, applying at the right time, at the right dosage and the right coverage. You probably missed one or more of the generations. Start spray applications in May. Apply every two months during warm weather. Read and follow the directions on the label. Use a “sticker” such as EZ Wet or equivalent, Apply to both the top and bottom of the leaves. The grapes are safe to eat. Just make sure you wash them.The netting is more for bird control than anything else. It is wise to delay putting bird netting over the top of grape vines until you start to see the berries turning color. I want to make sure you know information I’ve already posted on my blog previously. http://xtremehorticulture.blogspot.com/2014/09/grape-leaf-skeletonizer-attacks-again.html http://xtremehorticulture.blogspot.com/2014/05/concord-grapes-ravaged-by-skeletonizers.html http://xtremehorticulture.blogspot.com/2015/04/leafhoppers-hornworm-and-skeletonizer.html http://xtremehorticulture.blogspot.com/2014/04/grapeleaf.html

Skeletonizers Still a Problem on Grape Even If You Spray Read More »

Century Plant Yellowing: Water or Damage by Agave Weevil

Leave a Comment / why is my agave dying, Why is my Century plant turning yellow /

Q. A friend of mine is having trouble with his Century plants, Agave and Cactus turning yellow.  These plants are in a rock yard with hand watering, they are 2 years old. Last year he had something chewing a cactus and eventually lost the plant. This year he has had no chewing.  I hope you can help us without pictures. A. Two things come to mind when agave is yellowing this time of year…watering too often or agave weevil. Because this is the time that we see agave weevil damage below ground showing itself to our eyes above ground I tend to think of agave weevil. Particularly if it is century plant and this time of year. Treatment to prevent damage by this insect has to be done earlier in the season before they really get going on damaging the roots. I hope these links help. http://xtremehorticulture.blogspot.com/2011/04/april-is-time-to-treat-for-ag ave-weevil.html http://xtremehorticulture.blogspot.com/2012/09/agave-dying-suspected-overwat ering-but.html

Century Plant Yellowing: Water or Damage by Agave Weevil Read More »

White Fuzzies on Ash Growth

2 Comments / disease on new growth of ash, insect on new growth of ash, What is the white fuzzy growth /

Q. I have a 6-8 yr. old ash that has this white powdery looking substance on the newer growth. Can you tell me what it is and how to eliminate it.  Picture from reader of white growth on ash A.  I have seen this kind of “growth” on several vegetables and herbs as well including peppers and basil over the years. I have sent pictures of these two a good friend of mine, a well-known horticulturist in Arizona asking him what he thought they were. I could tell he was giving me his best guess as well but I don’t think he was very sure himself.  Here is a post on something similar I made back in 2012 http://xtremehorticulture.blogspot.com/2012/07/what-are-those-white-fuzzies-on-my.html Although not exactly the same thing it appears to be more insect related than disease or physiological in nature. I wish I could give you a better response than just to keep your eye on it and let me know if things get worse. If things do get worse, then I would direct you towards a soil applied systemic insecticide for the tree if it is needed. That is the best I can do for you at this point. Perhaps some are other readers might hazard a guess?

White Fuzzies on Ash Growth Read More »

Potatoes Need to Be Started Early in the Season

Leave a Comment / how to grow potatoes, what potatoes to grow, When to plant potatoes /

Q. I want to plant potatoes here in Vegas. Our season is timed different than others though so there aren’t seed potatoes available now for a mid or late July planting. Will standard Yukon Gold, Russett, fingerlings or Sweet Potatoes from the grocery survive here? Or can you suggest where to get some suitable seed potatoes? A. You are planting too late if you put them in the ground in July. We need to plant Irish potatoes here in late February or early March. Purchase seed potatoes early in the spring. Sweet potatoes are a hot weather crop and need to go in later when soil temperatures are warm, around the first week in late April or early May.             Any Irish potato can be quartered and used for “seed”. Potato seed are not seeds at all but cut up potato tubers. When cutting potato tubers for seed, make sure each seed piece has at least two “eyes” or “dimples” and plenty of tuber connected to it. Potato tuber developing on underground rhizome Sterilize knives used for cutting and allow the cut pieces to “heal” in the refrigerator, moistened, for a few days prior to planting. Warm up seed pieces taken from the refrigerator to room temperature before planting. I have used potatoes from the grocery stores for seed but you should realize that they are not certified disease free so diseases are more of a potential problem. Purchase organic potatoes for seed since standard potatoes may be treated with a sprout inhibitor. Sprout inhibitors are sometimes applied to keep them from sprouting in storage.   Harvesting potatoes All of the potatoes you mentioned will grow here including Sweet Potatoes. Consider Red Pontiac and Red La Sota for red skinned potatoes as well as those you mention. Also try blue potatoes such as “Adirondack Blue” as well as fingerlings. If you’re going to grow potatoes here, make them really special because regular old potatoes are not terribly expensive to purchase. I don’t know of a potato that will not grow here.

Potatoes Need to Be Started Early in the Season Read More »

Stop Watering Lawns at Night

Leave a Comment / brown spots on lawn, controlling lawn disease /

Q. I read with interest your column in the RJ on watering. Our small lawn seems to be dying in patches. We water 4 days a week for 20 minutes at 11pm.  We regularly feed with Turf Builder Plus and Ironite. What should we do? Lawn disease of reader. A. First of all change your watering time to 4 in the morning and finish before sunrise. Never put your lawn to bed at night, wet. You are asking for disease problems if you do. Most warm weather lawn diseases need about 6 hours of a damp, dark warm environment to get active. After a watering cycle, wait 30 minutes and push a long piece of rebar or screwdriver into the lawn in several locations. Make sure it pushes easily to 10 to 12 inches before you meet much resistance. If it does, then you are watering deep enough. If not, increase you watering until you can push it that deep. If deeper than this, reduce the minutes to 15 or so and repeat. Break your 20 minute cycle into three shorter cycles totaling 20 minutes and space them about 15 minutes apart.  This helps prevent puddling and runoff. This fall, rent a core aerifier and punch holes in the lawn. Verify your lawn every three to four years; more often if your lawn gets a lot of foot traffic. In lawns, nearly any iron product works so you don’t have to spend a lot of money on iron. Not true about other plants.

Stop Watering Lawns at Night Read More »

Lawn Maintenance Companies Should Recycle Clippings Back into the Lawn

1 Comment / mulching mowers, Recycling mowers /

Q. I live in a subdivision with 400 townhomes and a fair amount of grass that the HOA maintains. The lawn crew does a couple of things that I question. They keep the grass mowed pretty short; 1-1/2 inches.  Shouldn’t they wait until it gets about 3 inches and then cut only 1 inch off?  Wouldn’t this minimize evaporation? They are collecting the clippings and discarding them. Wouldn’t it be better for the lawn if the clippings fall back on the grass? Doesn’t the nitrogen recycle back into the lawn? A. They should be recycling the clippings back into the lawn and mowing higher. This will require that they use recycling mowers, a special blend of fertilizer with half of its nitrogen in the slow release form and closer lawn management. Mow tall fescue no closer than 1 1/2 inch at any time and 2 inches is better. This gives them 1/2 inch of growth they can remove safely each mowing. These grass blades contain a lot of fertilizer that end up in the landfill so it is better to recycle them back into the lawn. If removed clippings are an inch long, this tells me the nitrogen fertilizer applied is excessive. No more than 1/3 to 1/4 of the grass blades should be removed in one cutting. Measuring the average length of clippings is a good way to determine if nitrogen fertilizer is needed by a lawn or not. Mowing is important for controlling lawn diseases. Grasses are unique because they push growth from the bottom of the blade; the oldest growth is removed when mowing. Old-growth contains more disease problems than the newest growth. Lawn clippings can and should be returned to the lawn. If they do this successfully they must use recycling mowers and a quality lawn fertilizer. Returning lawn clippings to the lawn substitutes for one fertilizer application every year. Recycling lawn clippings back into the lawn improves its general health because lawn clippings are composted back into the soil, releasing nutrients. Recycling mowers have a unique blade and a unique deck design that provides greater lift and causes lawn clippings to be “chopped up” more effectively than with traditional mowers. Traditional mowers retrofitted with recycling blades will work but they are not as efficient as recycling mowers. If a recycling program is done correctly, you will not see any residue from lawn clippings left on the lawn after mowing. Fertilizers used with recycling mowers are unique. They must have a large percentage of their nitrogen in a slow release form or the fertilizer should be applied in much smaller quantities, more often. Their greater cost is offset because less fertilizer is required. Where I don’t agree with you is on water conservation. The research is conclusive that lawns mowed higher use more water than lawns mowed shorter. However, lawns with a deeper root system are more drought tolerant. So it is a trade-off. Lawns that are mowed higher have deeper root systems. This makes them more drought tolerant but they also use more water. This is misleading because the difference in water use between a closely mowed lawn and one that is mowed taller is not large. It is more important to have an irrigation system that is designed and maintained correctly and water applied when winds are minimal and adjusting your lawn watering schedule monthly during the spring and fall months. Lower water use is tied more closely to management of the lawn and irrigation system, not the root depth of of lawn grasses. Mowing a lawn higher has other benefits. Lawns mowed taller have deeper roots. Deeper rooting means better drought tolerance. Here is the rub. Improved drought tolerance alone has no relationship to low water use. It could be argued the opposite; they use more water. Water use of lawns in inches per day as the seasons change in Las Vegas. Months are January=1 and December=12 Bottom line. Lawn maintenance companies should not be bagging lawn clippings but returning them to the lawn using recycling mowers. They must be careful in applying nitrogen to lawns. Over applying nitrogen fertilizers causes lawn recycling programs to fail.

Lawn Maintenance Companies Should Recycle Clippings Back into the Lawn Read More »

Look For Clues to Spider Mite Damage on Cypress

3 Comments / how to control spider mites, mites on cypress, webbing on cypress /

Q. I have a group of Italian Cypress in my back yard.  I am completely new at this (growing trees and gardening) because I have lived in apartments and condos until recently.  I planted them, they looked very happy, but in early summer my gardener pointed out they were being attacked by spider mites and said I should do something quickly or they will die.  Well, they survived and did not die, and the new growth on top seems to be green but the growth on the bottom is still pretty brown.  I asked at a nursery and was told it will never green up and I have never seen needles fall from the tree, so I suspect he is right (though I am suspicious because nurseries sell trees).  My wife on the other hand is certain that, given a couple of years the problem will go away.  I was going to replace all the trees (they are like 15 feet tall and 3 years old, so they grow very fast) but that is upsetting my wife.  I would like to know who is right, the nursery or my wife (who did grow up around trees). Readers Italian Cypress A. I am in the middle on this one. I did look at the original pictures enlarged and it certainly could be spider mite damage. I would be looking for the needles having a “dusty” appearance (tens of thousands dead, cast “skins” of spider mite making a surface “dust” on the foliage. I would also look for perfectly round eggs with a magnifying glass or dissecting scope). Without seeing the branches in person and the extent of the damage it is hard to judge. If the damage has extended all the way into old growth in the interior they will not recover but be permanently brown. If the damage is light and there is some green growth remaining it is possible for them to slowly recover.  Electron micrograph of spider mite feeding Take the branches with dried “needles” and bend them strongly. If they are dry and snap they will not recover. If they are supple and do not snap like a dry twig they may recover. That is the best I can tell you. It may not have been spider mites. I would have to see the foliage very closely and inspect it for mite “residues”. Not all spider mites make webbing and some webbing is caused by spiders so seeing webbing alone does not guarantee it is spider mites.   Webbing like this may or may not indicate spider mites are present. Look for other clues too. During the heat of the summer I would hose down the Italian cypress once  a month or so or after any kind of “dirt” storm. Dirt or dust on the leaves interferes with the natural control of spider mites by predatory mites and beneficial insects. There is a natural “ecosystem” at work on cypress that keeps the bad critters under control. Spraying insecticides or miticides can interrupt this natural control system by killing off the beneficials. Do not irrigate Italian cypress too frequently. If watered often it can cause root damage and also create the same kind of browning. These are Mediterranean plants and do not tolerate wet soil during warm weather. Water them no more than about once a week if you have a “normal” soil but give them a thorough watering when you do.

Look For Clues to Spider Mite Damage on Cypress Read More »

Follow-Up Questions on Peach and Citrus

Leave a Comment / Uncategorized /

Q. A few months ago you told me how to help my grapes and other fruit trees (thanks for featuring my yard on the blog)! My citrus is turning black and dropping. The main issue I am having now is my peaches are turning a dull yellow, almost like a brown but not really. The photos don’t really catch it. I dug about 1 foot away from the plant to see if the soil was too damp and found that it was moist about 3-4 inches below. With the last watering cycle happening about 3 days prior. The plants get 5 gallons in the morning and 5 at night.  2 times a week. I did put some of “stress tonic” and a little iron just in case, but far less than the recommended amount. Readers peach tree As far as my tomatoes go, most of them are done or dying but produced heavily so I am pleased. I had a few watermelon which were quite tasty and they may reproduce again. My citrus are having a bit of a rough time most of the fruit turned black and fell off (in containers and get a few hours of partial sun.) although the plants are shooting new growth and even flowered again. Although this time not fruiting. Any advice or thoughts? Also should I prune them back any? A. Fruit dropping can be a sign that your citrus may be going through excessively dry periods before they are irrigated again. It can also be a sign that your trees are just too young to support fruit development yet and so the fruit was aborted. Citrus leaves can discolor, turn kind of a bronzy yellow, due to damage from the sun. You won’t see as much of this if they are growing in the ground and the surface of the soil covered in wood chip mulch. You can use an inexpensive houseplant moisture meter to get a very general idea what the moisture level of your soil is. Stick it in several locations so you get an idea of how the water is distributed. All fruit trees need at least six hours of full sun each day to produce an adequate amount of fruit. Roots of fruit trees growing in containers have the largest percentage of the roots that take up water and nutrients in the boundary area between the root ball and the container. This is also where the drying of the root ball occurs first. And containers exposed to direct sunlight will overheat the root ball on any side that is in full sun unless it is protected. You could lose as much as 50% of your root system if that root ball overheats from direct sunlight on the container. I looked at all of your pictures. All of the growth that I saw looked good for this time of the year. There was a lot of leaf cupping on your peach which can be due to heat. It was showing some signs of some water stress. This can be the scorching on the edges of leaves.  I did not see wood mulch on the soil beneath the trees. Your fruit trees would benefit 1000% if you can apply a layer of wood chip mulch, not bark mulch, on the soil surrounding the tree in a circle about 6 foot in diameter. The mulch should be 3 to 4 inches deep. This was an unusually good year for tomatoes. Don’t expect this type of production every year. When the spring months jump from cool to hot very quickly, tomatoes will not produce as well. Tomatoes produce much better if they are protected from excessive wind. You can do this by deflecting the wind away from the garden or putting up windbreaks. Fruit trees do quite nicely with one or two applications of fertilizer year. This is usually in the late winter and perhaps a second application after harvesting. I tell people to fertilize their vegetables and herbs monthly.

Follow-Up Questions on Peach and Citrus Read More »

Substitute Tree for Mesquite Without Pods

Leave a Comment / Uncategorized /

Q. I have two large Mesquite trees In my front yard…the kind that produce hundreds and hundreds of pods each year and then lose their tiny leaves in the fall as the wind whistles.  Quite messy to say the least.  However, they do provide considerable shade in the summer months. Response from Andrea Meckley: A. Bob Morris forwarded your question to me.  It’s hard to beat the shade mature Mesquite trees give, but as you say they do have pods drop.  The shade tress listed below will take full sun, are green all year so not much leaf drop, produce no flowers and are available locally in the Las Vegas area.   I suggest:  1.  Bay Laurel, standard tree form (mature size 12′ x 12′) 2.  Xylosma,standard tree form (mature size 15’h x 12’w 3.  Holly Oak (mature size 30′ x 30′) (produces acorns) The internet can give you more pics and characteristics about the trees listed.  Also SNWA.com has a plant search section that is very good with pictures and information. I hope this helps.  Please contact me with any further  questions. Andrea Meckley, Certified Horticulturist [email protected]

Substitute Tree for Mesquite Without Pods Read More »