Presidents Day Farm to Table Brunch in Moapa

It is not too late to register and go! Have a fabulous time in rural Nevada and enjoy beautiful Moapa!

Don't Confuse Leaf Drop with Ash Decline

Q. I have an ash tree which appears to be dying. I am considering taking it out but would like to have someone look at it before I do.

A. The usual problem here with ash trees has been a disease called ash decline or ash dieback. I have posted questions I received regarding this problem on ash trees along with pictures of what it looks like and what to do if you have it.

Ash decline

            Send some pictures to me of the tree showing the problem when you see the problem. I need close-ups of the leaves as well as a picture of the entire tree. Look at the pictures I have posted here or on my blog to confirm it. This disease is quite easy to identify from pictures.

            If you are certain the tree has this disease it should be removed. There is no cure for it.

This email was confirmed as ash decline and the tree removed.

Greenhouse Space Heaters Need Air Mixing

Q. I have a small greenhouse I would like to heat at night to prevent the freezing of some seedlings. I am guessing I will only need heat for the month of February. I was thinking of a small space heater.

A. It is much easier and more effective to provide bottom heat to warm seedlings than a space heater that only warms the air. Provide bottom heat by using waterproof heating mats beneath the seedling containers or trays. They are available locally from nurseries and garden centers.

            Many vegetables that grow during the summer months require warm soils for good germination. Seeds like tomatoes and peppers will fail or germinate very slowly if the soil is not warm.

Years ago we would place seedling trays on top of the television or refrigerator where it is warm enough to complete or speed germination. As soon as they germinated, they would be placed in some light or directly under very bright lights.

Drape plastic or a light blanket over the seedlings and heating mat at night and remove it during the day. Seedlings require 6 to 8 hours of full sunlight, or the same intensity from electrical lights, as soon as they germinate. Sunlight intensities or durations shorter than this will produce spindly transplants that will grow and transplant poorly.

You don’t need expensive grow lights for growing transplants. Fluorescent lights or LEDs are fine but they must be placed within an inch of the leaves to produce enough intensity to support good plant growth.

Be very careful when using incandescent bulbs, or lightbulbs, for growing seedlings. They produce a lot of heat and damage plants at distances close enough to produce enough light intensity. I leave electrical lights on about 16 hours each day when growing transplants.

Plum Sap Not Always Disease or Insects

Q. My plum tree has sap coming from it in bubbles. Does it have some sort of disease?

A. Sap coming from a tree is a response by the tree to some sort of damage. Damage that causes sap to ooze in bubbles from the trunk or limbs can be caused by the environment, disease or insects.

Plums are normally very sappy. When plums are pruned during the growing season they respond to fresh wounds by releasing a large amount of sap. Trees that produce sap in response to damage or an attack is their method of protecting themselves.

Sap losing from cut limb on plum

When insects that burrow into the tree and attack it, such as borers, the release of sap can engulf these burrowing insects and suffocate them. If the burrowing insect is still active, chewing and feeding away when sap is released, these bubbles of sap will be dark in color but cloudy. The sap is cloudy because it is full of sawdust or wood chips from the feeding by these chewing insects.

If the tree successfully engulfs and kills this destructive critter, the sap continues to be dark but free of sawdust or wood chips and therefore clear. Sap also helps flush disease organisms from wounds.

The presence of sap from plums and apricots does not always mean there are disease or insect problems. Sometimes environmental damage to the tree can cause sappiness. Environmental damage can occur from intense sunlight, heat and water stress.

Take a sharp knife and remove the bubbles of sap all the way to the surface layer of the tree. Remove the surface layer of the tree so that you can see what’s going on just under the bark. Look at the exposed area under the bark and inspect it for insect damage. You may find the insect itself.

Regardless, it is a good idea to remove the sap bubble and inspect the exposed limb or trunk just under the bubble. If an insect or its damage is present, clean out the damaged area so that everything looks healthy and the tree can heal on its own.

There is no reason to apply anything to this wound afterwards if the knife was sanitized first. Use alcohol to sanitize the knife, heat from a lighter or household sanitizer such as Pine-Sol. Be careful with bleach, (even though it is a good sanitizer) because it rusts tools and destroys clothing.

No Fear of Disease after Spraying Liquid Fertilizers

Q. Can foliar spraying micronutrients like iron on fruit trees cause bacterial leaf spot to form or spread? I have had problems with bacterial leaf spot on my nectarine trees but last year the leaves weren't affected as much. I don't want the pathogen to spread again.

A. Where do you live? Who made this diagnosis? I have not heard of bacterial leaf spot forming in the dry desert. In more humid climates it can be more common. The leaf spots on leaves should be surrounded by a yellow halo if it is bacterial leaf spot.

Some iron sprays can cause staining on developing fruit and can resemble disease. This is iron staining quince fruit. Use iron chelate sprays if fruit is present.

Bacterial infections usually require wet or humid environments and warm to hot temperatures or insects to spread the disease. And these wet/humid environments must be present over a long enough period of time usually many consecutive hours.

It would be possible if the plants are crowded together so that the leaves cannot dry or there is an air movement to help dry them. Overhead irrigation such as sprinklers could also contribute to a problem.

However, applying foliar micronutrients early in the morning so the leaves have a chance of drying before nightfall there should not be a problem. And spray early in the season.

Some diseases like shot hole fungus are prevented with properly timed fungicide applications containing copper. Copper fungicides can also be used to help prevent some bacterial infections like bacterial Leaf spot.

The pathogen or bacteria are already present on stems and move to the foliage early in the spring. The leaves just need the right environment (temperature and humidity or degree of wetness) to cause infection.

It also helps if the canopy is not dense so there is air movement to help dry the leaves. In your pruning you should create enough space between branches to allow for some sunlight to penetrate inside the canopy and reduce shading.

You probably have been told that there are not many pest control products for bacterial diseases but a fairly common fungicide like Bordeaux can give you some good protection if applied when temperatures get warm. Some of the disease potential can be removed through pruning in the winter.

Prune Lantana and Star Jasmine at Different Times

Q. When can we cut back star jasmine and plant lantana?

A. Because Lantana could still freeze back with some low temperatures it is best to wait until the end of February to plant them. Now is a great time for planting anything not damaged from freezing temperatures.

Flowers produced by one of the Lantanas

Dig a hole three times wider than the container. Use soil taken from the hole and amend it 50/50 with compost plus a handful of granular fertilizer high in phosphorus. As an alternative, mix a water-soluble fertilizer high in phosphorus in a bucket with water and use this solution when watering the first time.

Unopened flowers on star jasmine

            The general rule of thumb for when to prune plants appreciated for their flowers is to prune soon after the flowering period has finished. This is because the flower buds for the next cycle of blooms are formed soon after flowering is over. Pruning now could eliminate the spring flowers.

New spring growth from Lantana after it is been cut back to a couple of inches above the soil or rock mulch level

            After pruning, always fertilize plants. Flowering plants should receive a high phosphorus fertilizer at least once during the year.

Drop Olive Fruit with Chemicals but Don't Eat Them

Q. Last year our Olive tree had lots of fruit on it and was very messy. Can you tell me when we should spray the tree to keep it from fruiting next time?

A. Olive flowering peak is around mid-April. The usual homeowner chemicals are Olive Stop and Florel Fruit Eliminator. They work a bit differently.

European Olive flowers

Florel can be applied once before the flowers open, but Olive Stop must be applied two or three times. These times are when flowers are first opening, again when most are open and a third time when the late ones are opening.

The spray schedule for Olive Stop can last up to two weeks depending on air temperatures. Cooler weather causes flowers to open more slowly than hotter weather. This causes our spray season for fruit control to be longer.

European olive flowers growing in the axils of the leaves

For flower and pollen control, Florel is probably a better choice, but it is a bit more toxic to the trees than Olive Stop. For just fruit control, Olive Stop is fine. Any plants beneath the trees should be sprayed with water immediately after these chemicals are applied to remove what falls on the leaves and minimize any damage from the spray.

With Olive Stop, the chemical has to reach the flowers as much as possible. This is not necessary with Florel. Watch for sales on these products as we get closer to April.

Commercial applicators have a little bit more selection because they can use products that you can’t. They have products called Embark and Maintain, which are different from homeowner products.
Remember that these chemicals do not prevent flowering but only the production of fruit. To prevent flowering (pollen) use chemicals such as Maintain, a chemical normally applied by professionals.

Remember that olives coming from trees that have been sprayed should not be used for human consumption.

Prevent Grub Attacks Now Safely

Q. I seem to have grubs in one area of the planting areas around the house.  

What do you recommend to eradicate grubs?  I have roses and a few ornamentals in these beds.

A. Try beneficial nematodes for grub control. Once they have been added to the soil they live their a long time if they have "food" (grubs) to feed on. Safe for plants and animals.

I would like to connect you to a few of my posts on my blog.

http://xtremehorticulture.blogspot.com/2012/07/grubs-in-container-of-garden-soil.html

http://xtremehorticulture.blogspot.com/2014/05/is-grub-guard-safe-to-use-in-my.html

http://xtremehorticulture.blogspot.com/2015/10/control-root-eating-grubs-organically.html

http://xtremehorticulture.blogspot.com/2014/09/controlling-grubs-is-big-topic.html

http://xtremehorticulture.blogspot.com/2014/08/poor-growth-of-lantana-due-to-grubs.html

http://xtremehorticulture.blogspot.com/2015/05/look-for-plants-dying-because-of-grubs.html

You can find these sometimes in your local garden supply store or nursery. Or you can order them online. Try this place on the internet and read up about what they can and can't do and order the right amount and the right kind.

http://www.buglogical.com/beneficial-nematodes/ 

Use Traps on Fruit Trees Not Insecticides

Q. I was reading your blog about peach tree bore and I am planning to buy some pheromone traps. Which traps and lowers should I buy?

A. In southern Nevada we do not have peach tree borer. We have borers that get into peach trees but these are not peach tree borers. They are thought to be the flat headed Apple Tree Borer and/or the Pacific flatheaded borer. To my knowledge neither have lures and no way of trapping them using pheromones.

Pheromone traps can be very effective at removing some pests that attack fruit trees or fruit but there are not pheromone traps for every pest. Pheromone traps are highly selective and very effective at luring a very specific pest to the trap where it is stuck to a very sticky surface. You must be 100% certain of the pest you are trying to lure or it will not work.

This is the sticky bottom of a winged trap. The reddish-brown upright capsule in the center is made of soft rubber impregnated with the sex attractant called a pheromone.

            In this case you mentioned peach tree borer. This is not the insect we are trying to attract. We do not have this pest in Southern Nevada so if you buy a trap for peach tree bore you are wasting your money.It is a problem in more northern climates such as Central Utah, Colorado and California.

            The pest we are interested in is the peach TWIG borer, not the peach tree borer. The peach twig borer attacks new growth in the spring, killing it, then later generations attack the soft fruit causing “wormy peaches”. Occasionally we find this “worm” in apricots, nectarines and almonds.

This is the kind of damage we see very early in the season by the peach twig borer in new growth of peach and nectarine. This insect builds its populations through the growing season until finally it will attack ripe fruit. It may also attack apricots and almonds.

Pheromones are chemicals released into the air by one sex of an insect to attract the other sex so that mating is a sure thing. Pheromone traps use a capsule laced in pheromones that mimic this sex attractant. This capsule is placed inside a very sticky trap. The insect of opposite sex flies to this trap expecting to find a mate but gets stuck instead.

This is peach twig borer "worm" or larva in mature peach just harvested from the tree. This is the insect that is responsible for "wormy peaches". The adult is a small moth.

Pheromone traps were designed primarily to inform farmers when these bad insects were flying so that an appropriate pesticide could be applied exactly at the right time. Otherwise farmers are left to guess when to make these applications.

Coddling moth damage to apples or "wormy apples".

Under some circumstances pheromone traps can be placed in fruit trees to trick the opposite sex and catch them before they mate. If the pheromone trap is very effective at catching these insects then no insecticide needs to be applied. This type of insect control is sometimes called “mating disruption” or “trapping out” the problem insect.

Here is a winged trap for peach twig more hanging in a peach tree with the pheromone capsule located on the sticky bottom.

Pheromones are made for many different types of insects that are problems for farmers but the two insects I usually place pheromone traps out for in southern Nevada include the peach twig borer and coddling moth for apples, pears and quince. These will vary depending on where you live.

I prefer winged traps over the so-called Delta traps. I seem to get a better catch with the trap that is open on all sides.

This is the Delta pheromone trap. I think it works fine for detecting when the insect is present but I do not like it as much as the winged trap for mating disruption. I think the winged trap works better for mating disruption because it is open on all sides.

Even though it said it's not supposed to work, I have been very lucky trapping out both of these insects with lures and traps rather than applying insecticide sprays. I put my traps inside the Orchard perimeter so they get some protection from wind. I flood the area with the pheromone scent from these lures and it appears that they are confused enough that few find their mates.

Coddling moth damage on pear in Afghanistan. Damage is the same but the timing is different.

I start put out a single trap of each in about April in Las Vegas because I don't want to miss the first flight. However, I usually don't start catching them until about May. Their appearance coincides with heating degree days over a certain baseline temperature. These heating degree days can vary depending upon the weather so emergence can be earlier or later in some years. It also varies with the climate in your area.

Peach twig borer in the outer husk of almond. It usually does not get in the nut or kernel but can.

As soon as I start catching moths in the traps I immediately deploy the rest of them flood the area with this pheromone. I change out the sticky bottom once every two weeks or so and the lures are changed out monthly. I don't listen to closely to recommendations because they are for monitoring and not for mating disruption. Because I don't have hundreds of trees I choose to spend a little bit more money on lures and traps rather than pesticides and applying sprays.

I use one trap for about 20 to 25 trees. I replace the bottoms every couple weeks when trapping because of dirt and moths getting stuck in the traps and making them less sticky.

Buy enough sticky bottoms and lures to last from April until you harvest. Keep the lures in sealed plastic bags in the refrigerator until you are ready to use them. Technically you are not supposed to put them in the same refrigerator as food. Sticky bottoms and traps last from year to year but lures should be purchased fresh every year.

If you want a class on how to do this let me know and I will put one together.

Lemon trees in Containers Need Repotting

Q. I have two lemon trees, both about three feet high, in containers. My Myers lemon is about 10 years old but leaves get fewer and fewer producing only three lemons last year. When is a good time to repot it? 

A. Citrus does better in the ground than in containers. Extra management and care is needed when grown in containers. Containers allow more flexibility in freeze protection but trees growing in them are difficult to irrigate properly.

Newly planted 5 gallon citrus in 24 inch box. Box containers are good for a couple of years before they begin to fall apart and no longer hold water.

The usual reason for poor fruit production in citrus, particularly Myers lemon, is freezing temperatures around bloom time or shortly after. They like to bloom in January and February when freezing temperatures still occur. It only takes a light freeze to kill flower blossoms that are unopened, opened or small fruit that has just formed.

Be careful of soil mixes added to containers. Some soil mixes are not very good. Pick a soil mix that has a good reputation, not the cheapest one on sale.

A good time to re-pot them is now. Lay the container on its side and gently pull the plant and its root ball out of the container. Wash the inside of the container thoroughly.

With a spray nozzle, wash some of the soil mix from the root ball. Remove about one quarter of the roots with a sharp and sanitized pruning shears.

Look at the roots and see if they are healthy. The newest and smallest roots should be a creamy white color.

Slide the plant back into the container and push both upright. Locate the plant and root ball in the center of the container and add fresh container mix. Adding water with a hose will wash the soil mix into voids and remove air pockets. Gently lift the plant so that soil can wash under it and elevate the plant to the same depth it was previously.

Fertilize the plant with a fertilizer suitable for citrus. A rose fertilizer or fruit tree fertilizer will work if you can't find a citrus fertilizer.