Xtremehorticulture

Xtremehorticulture of the Desert

Grapeleaf Skeletonizers Flying Now in Las Vegas

2 Comments / grape leaf eaten, grape leaf skeletonized, veins remaining /

Q. My grape vine is started to leaf out. What is the spray I need to use to prevent the leaf eaters? I saw a black wasp like bug today (April 9) A. That black wasp-like insect was actually a moth and does not sting. But she will be laying eggs on the undersides of grape leaves. These eggs hatch in a few days and the larvae that emerge will begin to consume the leaf from the underside, often times in a row, leaving the leaf veins behind. For this reason we call them grapeleaf skeletonizers. Great picture of skeletonizer eggs and larvae hatching on the leaf underside from reader. Also very good picture of adult by reader Be careful of these larvae. If they land on your skin they will “burn” and give you a lot of pain. Use Bt sprays such as Dipel, Thuricide or Spinosad spray will also work. The sprays MUST be directed toward the undersides of the leaves as well as the tops. So plan on two passes over your grape vines; the first time on the underneath side and the second one over the top. Spray the leaves enough to give the leaf surface a light coating on both sides. It does not have to be sprayed until the leaves are dripping wet. If you have a spreader/sticker to add to your spray then all the better and it will give you better and longer lasting control. Both sprays will also control the hornworm which can consume leaves voraciously. Leafhopper feeding damage to grape leaves. You will also see tiny black specks left behind (poop). These are tiny bugs that hop like a very tiny grasshopper but usually in the thousands on leaves. Spinosad has the additional advantage of giving you some control of leafhoppers if those have been a problem in the past. The Bt sprays do not. Make two applications. One now and one more about a week from now.

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Planting and Watering Ocotillo

Leave a Comment / how much water does an ocotillo need, how to irrigate ocotillo, how to plant an ocotillo /

Q. I have a recently planted ocotillo. It is tied together by wire when should I cut the ties?  Also, I heard that I should spray the plant with water frequently. What’s frequently? A. You can cut the ties after it is planted. Make sure it is planted the same depth it was when it was dug up. It will help to stake it until it gets established.             The biggest problem is from watering too often and the soil not draining adequately. Ten gallons once every two weeks this time of year is enough.             You can spray the stems each time you water. It is thought that ocotillo can absorb water through its stems but not really proven. Lightly mist it when you water. You can use a spray nozzle set on mist.

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Rose Flowers Small and Wilting May Be Damage from Thrips

Leave a Comment / not opening, rose flowers wilting, thrips damage /

Q. I recently had my yard refreshed with a new irrigation system,  new plants, rose bushes and even a small tree. My roses had suffered badly the last couple of seasons. No matter what I did, the mealybugs and aphids were victorious. Even if my roses bloomed they were small and quick to wilt. I had the landscaper change the soil this time and added wood mulch to the bed. The leaves as they came in were fantastic. Gorgeous colors and so full. Then came the  first signs of the aphids. My landscaper told me to get some ladybugs in the Spring, which I did. They seemed to do the trick for a while, then, came the bites in the leaves and a return of the aphids (if not in as great abundance). Finally, before my buds even opened it looked as if they had been burned at the edges. When they opened, the black peppered the edges of the petals. imidacloprid I’m not a great gardener but I love these roses and had real hopes for them this season. A. From your description it sounds like Western flower thrips damage. They attack the petals of flowers before they open and cause browning and wilting of flower buds. You can apply Spinosad for some organic control but you will have to apply it multiple times about a week apart to get any kind of control. Orthene sprays will work to some degree as well. Another product to try is an insecticide that contains imidacloprid in the ingredients. One such product is at Viragrow and probably some nurseries as well.

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Apricot Leaves Cupping and Dropping Off

Leave a Comment / stinkbug damage, what damage does a stinkbug do /

Q. My Blenheim apricot tree is not doing well. A few branches have lost all their leaves. Other leaves are starting to curl and cup. This year it had plenty of apricots but few leaves. I thinned them out since the tree is young. I thought this would also help the tree put more energy into leaves. Note: since this response we have looked at the tree and determined the leaf cupping and marginal burning was probably due to stinkbug feeding when the leaves were first emerging from the buds. A. First thing, I see you have wood mulch. Please pull it back 12 inches from the trunk. The symptoms you sent to me could be that. The cupping is because the outside edges of the leaves dried up and the leaf was still growing so the inside of the leaf still expanded while the dead edges did not. The edges of the leaves dying could be lack of water, salt damage, wind damage, damage from sprays. The lack of water could be either from a lack of applied water, damage to the trunk (mechanical or borers). Salt burn can be from applying fertilizer too close to the trunk and/or heavy rate of conventional fertilizers in the irrigation basin. Always keep fertilizer at least a foot from the trunk. When watering the fertilizer into the soil try not to flood the basin around the tree if you put a considerable amount of high nitrogen fertilizers such as ammonium sulfate or urea in the planting area. Urea or even “hot” manures like chicken or other poultry manures can cause problems like this if they get too close to the tree. Wood mulches surrounding young fruit trees and left in contact with the trunk can cause the trunk to rot effectively choking the tree at its base and causing it to act like it is not getting enough water (leaf scorch), dieback or death. This is called collar rot, crown rot or Phytophthora rot. Upon inspection of the tree if you have pulled the mulch back, inspected the trunk just above soil level and see no problems, inspected the trunk and see no signs of borer damage and ruled out possible damage from fertilizers then perhaps we can look at any sprays you might have applied and possible spray damage to foliage and fruit or damage from strong winds. Fruit trees do perform better with some windbreak in their growing area that either slows the wind down or causes it to be diverted to a different place.

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How to Use Organic Pesticides Effectively

1 Comment / how to spray organic chemicals, what organic pesticides to use on vegetables /

Organic pesticides work but they are aimed more for prevention than correcting an existing problem. Most pesticides or pest control techniques in organic production are aimed at preventing a problem from occurring rather than destroying hundreds of pests that are already causing damage. It is important to start organic control measures early in the growing cycle and treat regularly. Organic control measures don’t involve just spraying with so-called “organic” pesticides but they involve a series of measures that help reduce pest problems. Many involve integrating techniques that dont involve sprays with the use of organic sprays. 1. Buy clean plants at the beginning. If you buy plants that come from “dirty” greenhouses or are grown under “dirty” conditions you are inheriting a problem. Inspect the plants and buy healthy plants at the start. 2. Treat plants with organic sprays before you plant them. Get them as clean as you can before you plant. Wherever your plants were grown, you will be planting the growers problems along with your own. 3. As plants get larger, thin the canopies if they need it and remove lower leaves that are shaded. Leaves in the shade of the maturing plant do not contribute to its overall health but can and will detract from it. Lower leaves provide places were insects and can hide and multiply. Pesticide sprays are most effective if directed to the undersides of leaves.Lower leaves don’t allow for even application of sprays and good pest control. Removal of these leaves helps reduce pest problems and make it easier to spray. Thinning the canopies of tomatoes, peppers and eggplants helps air ciculation and reduce disease problems. Staking tomatoes helps reduce fruit losses due to spoilage. Leaves growing in shade actually take energy away from the plant and slow its growth. Lower leaves are homes for insects that will multiply and infest your plants. Look under those leaves and see for yourself. You will usually see aphids and other plant pests hiding and multiplying there. Removing them helps air circulation, reduces plant pest problems and helps you achieve better pest control. 4. Get more than one type of spray for your plants and use them in rotation. Using one type of spray over and over will cause a buildup of insects that are not affected by that spray. It is best to have several different types of sprays that are effective on different types of problem insects. A good selection might include an insecticidal soap, oil of some sort like Neem or horticultural oil and Bt. 5. Spray in the early morning hours or early evening hours when bees have gone home. Most organic sprays are nonselective and cannot tell a good insect from a bad one so in most cases both will be killed. 6. Keep plants healthy  by fertilizing plants regularly. Usually a light application of a fertilizer once a month is enough to keep them actively growing and in production. If you are harvesting from a plant you are taking away from the plant. It is also important to “give back” to the plant in the form of small amounts of fertilizer. 7.  Rotate your crops and dont plant vegetables in the same families in the same spot year after year.

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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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Stinkbugs Cause Plant Damage Early in the Season

1 Comment / brown mamorated stinkbug, do we have stinkbugs in nevada, leaf cupping, leaf scorching, poor growth /

Most gardeners recognize the stinkbug in southern Nevada. But the populations may be on the rise in home gardens particularly early in the season. Stinkbugs were not a big concern when we saw them in home landscapes and gardens in southern Nevada in the past. But recently I was at a home to inspect some damage on apricot leaves early in the season when the leaves were first coming out. Cupping of leaves early in the season can be caused by feeding damage of insects like the stinkbug on new leaves just expanding from leaf buds. Not much for these insects to feed on early in the year and new growth is soft, succulent and available. The homeowner sent me some pictures of leaves that were cupping and scorching on the edges like the one above. I didn’t really spend too much time on it, just that it was a sign that there was early damage to the leaves before they got large. Then as the leaf expanded and got larger the undamaged part of the leaf toward the middle kept expanding while the damaged edges did not. This causes the leaf to “cup”. While visiting this homeowner and seeing the damage to the tree in the picture above the homeowner spotted the stinkbug on the branch and pointed it out to me. And I thought yes, that insect feeding on leaf tissue from expanding leaf buds could cause this type of damage. Stinkbug photo courtesy of reader This particular type of bug has a long sylet, like a hypodermic needle, for its mouth sort of like a mosquito that can suck blood. This long stylet can be inserted into soft tissue like expanding leaves or young leaves, even young fruit, and “take a drink” with that hypodermic snout it has. This bug does not want to damage plants but does need to feed. In the process of feeding it causes plant damage. Sometimes it can be holes in leaves, damage to expanding leaves and even sap exiting from young fruit. Luckily they are easy to kill if insecticidal soap is sprayed directly on them. Otherwise you will have to rely on insecticides that leave residual poisons so they come in contact with it. Most insect sprays for fruits and vegetables will work.

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Apricot Fruit Needs Little Thinning

Leave a Comment / does apricot fruit need thinning, how to thin apricot fruit /

Apricot fruit doesn’t need thinning….or does it? Remove deformed fruit or fruit that has set too close together. You will know they are too close if they will push each other off of the tree when they get larger. This apricot fruit will begin to push each other off of the tree as they get larger. Just enough fruit was removed to give the remaining fruit some room to grow and expand without knocking each other off. Some varieties of apricot have plenty of room for their fruit to expand. Other varieties will set their fruit too close together.

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Thinning Apple and Pear Fruit is Similar

1 Comment / how to get larger fruit, how to remove fruit, how to thin apples, how to thin pears /

Apple and pear fruit are produced in clusters of fruit on the tree. Leave only one fruit remaining in each cluster. Remove all but one of the fruit (in the desert we can leave two fruit on if we do not have many insect or disease problems and there are plenty of fruit on the tree). European pear with many small fruits formed in a cluster. Remove all but one of the fruit in the cluster. If there are not that many clusters on the tree, leave two fruits remaining from the cluster. Twist or cut off excess fruit. European pear fruit in clusters before thinning European pear fruit after thinning. Leave one per cluster. Twist or cut off excess fruit. Apples fruits are borne in clusters in spur-type apple trees. If you have a spur-type apple tree then leave one fruit per cluster as you would with European pears as well.

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