What Causes Apricot Fruit to Drop?

Q. I've had my apricot tree about 15 years. Last year it had a huge crop. This year it had lots of blossoms, swarms of bees, but almost no fruit set. The remaining fruit has dropped off. There is sap on one of the branches and I'm wondering if it has bugs or is it just is taking a year off?

Plum fruit turning yellow due to lack of fertilization (talking flower sex, not fertilizers). Other fruits, green, set. The yellow
ones drop from the tree during "June drop" which actually occurs in April here. Yes, I know the question is about apricots but
I do not have any apricot pictures like this.

A. Some fruit trees do take a year off. This is called alternate bearing. However, alternate bearing decreases fruit production by reducing the number of flowers, not the dropping the fruit. Unless the tree is dying I doubt it is due to sap and the bugs.

See the "yellow" plum getting ready to drop? It will abort. The green ones
will continue to develop.

Flowering, followed by the dropping of small fruit, usually indicates poor pollination. Small fruit drops because the pollen was not transferred to the female part of the flower. Or, if it was transferred, it did not result in fertilization.

When fertilization doesn’t occur, fruit may still form, grow a little bit in size, but then yellow and abort or drop from the tree. Fruit abortion typically happens when the fruit gets about the size of a dime or even smaller.

Healthy fruit may abort if the soil is too dry. When soil dries, fruit trees will try saving themselves by first dropping fruit and, if the threat persists, dropping leaves as well.

If weed killers are sprayed close to a tree and the spray (even fumes from the spray on a hot or windy day) may drift toward the tree and cause fruit drop.

Applying too much fertilizer close to the tree trunk can also cause fruit drop.

There are a couple of older apricot varieties that need pollinators. If it is one of these varieties and a neighbor's tree died that was pollinating it then this might also be a problem.

Inspect your tree for insects. Some insects, such as the leaf footed plant bug, can cause fruit drop. If your tree had a large number of these insects feeding on small fruit, it could cause fruit drop. 

Black Spots on Tomato Leaves May Be Septoria

Q. I have these small black spots developing all over my tomato leaves. Any idea what is wrong with my tomato plant? 

Possible Septoria leaf spot disease on new transplants

A. From your pictures it looks like you could have a couple of things going on. The tiny black or brown spots on the leaves may be a disease called Septoria leaf spot. As a precaution, I would apply a fungicide for vegetables immediately and follow the label directions to a tee.

Any general fungicide for vegetables will work. It usually requires several applications in sequence. Push some new growth with a light application of a tomato fertilizer.

Another shot of possible Septoria.

Fungicides are primarily meant for disease prevention, not for curing a disease once the plant has it. Applying a fungicide protects new growth as it emerges so new growth should be healthy while the infected growth does not get worse.

The other option is to pull it out and start over.

Secondly, never apply irrigation water with a sprinkler; use drip irrigation.

If you bought these plants from a local store it probably came with the plant when it was grown in the greenhouse and shipped to the store. This disease is fairly easy to control if a greenhouse is kept clean and the plants kept healthy.

Such is the problem when buying low-priced transplants. They were most likely infected when you bought them. There were probably some leaves already showing these spots.

Your other pictures show leaves of tomato with edges that are scorching. These scorched margins have a yellow inner margin. This is possible salt damage.

Reminds me more of salt damage but ......

Soak the soil with water. Use a soil wetting agent like EZ Wet or comparable and apply it to the soil to remove salts. Hopefully you amended your soil with compost at the time of planting and you used a pre plant fertilizer.

Also some leaves showed signs of yellowing which may be due to lack of fertilizer applied at the time of planting. Once tomatoes start setting fruit it is important to feed them lightly to continue healthy growth.

Take a look at these fact sheets and pics.

Cornell's Fact Sheet on Septoria on Tomato

Missouri Botanical Garden Fact Sheet on Septoria on Tomato

Deformed Lilac Leaves Maybe a Sign of Problems

Q. My lilac bush had some leaves on it that suddenly look like they are deformed. What is the problem?

A. Deformed or crinkled leaves can indicate several things. If the edges of the leaves were damaged, scorched, the interior of the leaf will continue to grow while the dead margin will not. This can cause leaf deformity called cupping.

Stink bug

Feeding damage by some bugs on leaf buds before they open can cause crinkled or deformed leaves. These include the stink bug group of insects such as the leaf footed plant bugs. Look for bugs on the
bottom of the leaves or crawling on stems.

Leaf deformity can be caused by “weed killer” sprays that drifted on the foliage during windy or hot weather. Some herbicides, like dandelion killers for lawns, cause leaf deformity if it comes in contact with leaves as they are enlarging or expanding.

Squash bugs, one of the stink bug types

Bottom line, most likely the damage is temporary and as more leaves develop they should be normal. However, if you inspect the plant and see these types of insects apply an insecticide for ornamental plants and spray leaves and stems during early morning hours. Spray the undersides of leaves because this is where most the bugs hang out.

Make sure the plant gets enough water. This is a plant that likes compost and wood mulch, not rock mulch. Lilacs do not like rocks covering the surface of the soil. Every year apply 1/2 cubic foot of compost on top of the mulch and water it in. Use a high phosphorus fertilizer that promotes flowering of woody plants.

Mildew on Roses Have Common Link

Q. My roses are covered with mildew.  I have sprayed them and hope they will recover.  I have not had this problem in years.  What causes mildew and how do you keep it from coming back?

Powdery mildew of roses, severe

A. Diseases develop on plants when the environment is just right for that disease, disease organisms come in contact with the plant and the plant must be susceptible to it.

Let’s break each of these factors down. Remember, when dealing with diseases it is most important to prevent diseases from happening rather than cure them with a pesticide after the fact.

Powdery mildew of roses, or powdery mildew of any plant for that matter, develops best in shady spots during cooler times of the year and when it is moist. It does not like to develop in full sun and when it is hot and dry.

We see powdery mildew during cool weather of spring and fall and times just after it rains. It is common when roses are grown in shady spots and watered with sprinklers.

Powdery mildew of weeds

Powdery mildew can be spread by splashing water. This can be from rain or sprinklers. It can also be spread by hands, pruning shears and wind.

Powdery mildew likes some roses better than others. The variety of rose and how healthy it is has a lot to do with how often you will see powdery mildew on it.

So if you want powdery mildew on roses then grow a variety susceptible to powdery mildew, don’t fertilize it very often, prune it incorrectly, place it in the shade and water it with sprinklers.

The flip side is best for disease free roses: select a variety resistant to powdery mildew, plant it in at least 6 to 8 hours of full sun each day, apply compost and wood mulch to the soil, keep it healthy with at least one application of a rose fertilizer every year and irrigate using drip irrigation.

These links may help you with some general information on powdery mildew.

http://xtremehorticulture.blogspot.com/2014/12/euonymus-plants-have-white-spots-and.html

http://xtremehorticulture.blogspot.com/2015/01/pick-right-variety-of-roses-for-desert.html

Hugelkulter Mound in the Desert?

Q. I have been reading about building a Hugelkulter mound. My husband and I are in our 60's and the less we have to be on our knees the better it is for our backs. I wonder if we could build a Hugelkulter mound out of desert materials? Every article I've read seems to be in a forested area where wood is readily available.

A. I have to be honest with you. I have never heard of this before so I had to do some digging (not literally) into the subject. I also have to admit I don't know anything about it but I did find someone to refer you to. I met her a couple of weeks ago at a class I was teaching in Arizona.

Hugelkulter on Wikipedia

She is a permaculture advocate and a delightful person. I have not visited her place in Arizona but she is enthusiastic and someone I would recommend you contact for more information.

Christine Baker

928-564-2642

christine@highdesertpermaculture.org

www.highdesertpermaculture.org

Perhaps there are others out there who can chime in. Let's all remember this IS the Mojave Desert.

Consider Banks Rose in Desert Landscapes

Bank's rose is not a repeat bloomer so it only blooms once in the spring. The rest of the year it is green.

Yellow Banks Rose

Trellised for a western exposure and filtering light on a hot summer entry. Spring.

Fuzz Balls on Oak Leaves Damage

Q. I found these fuzzy things on my oak leaves. What are they and should I be concerned?

Oak leaf gall caused by  tiny wasp

A. These fall under the general category of plant galls. Galls are swellings of plant tissue and located on the roots, stems, trunk, leaves and flowers. Galls can be caused by insects, diseases, nematodes or mites.

This particular gall is on the leaf of oak, and my guess it is ‘Heritage’ live oak. These leaf galls are very common to oak and caused by a tiny wasp. The purpose of the gall is to protect the developing youngster until it is mature and exits the gall to find a mate.

Later on in the season you will see a small exit hole and the gall will probably turn brown or the leaf may turn brown and drop from the tree if the infestation is quite severe.

Ash flower gall caused by eriophyid mites feeding on flower buds

The basic lifecycle is for the female to lay an egg inside the leaf or on a leaf surface. The egg hatches and the very tiny larva eats the plant tissue inside the leaf. It also releases chemicals that control the growth of the leaf around the area where it is feeding.

This disturbed area grows in response to the feeding and causes the leaf to grow into a tumor-like growth totally surrounding the youngster. Inside this gall the youngster can continue to feed protected from predators and the environment.

Eventually the youngster grows up into an adult and exits the gall in pursuit of a mate. Once the mate is found, the life cycle repeats itself. In some cases a large number of these wasps can exit numerous galls and build a large population that can cause leaf drop.

These leaf galls normally don’t present a problem and I would just ignore them. However if they do create a problem you might consider applying a tree systemic insecticide to the soil surrounding the tree near the source of irrigation water. I would apply it as soon as you see leaf galls developing in the spring.

A picture of this same oak gall appears at this website by Armstrong with a short description along with a bunch of other galls. http://waynesword.palomar.edu/pljuly99.htm#insects

You can learn more about plant galls by visiting this website located at Brandeis University.

http://www.bio.brandeis.edu/fieldbio/Plant_Galls/samplepage.html

Leaf drop could also occur from excessive shade and a lack of water or applying water too often. You should not be watering daily. All it takes is one or two missed irrigations and you could have leaf drop from a lack of water during hot, dry weather.

Watering too often would cause root rots and leaf drop and a sudden death of the tree during hot weather.

Applying a heavy dose of nitrogen fertilizer close to the trunk could also cause leaf drop and possible tree damage.

No Water? No Vine.

Q. Is there any decorative vine which will prosper in Southern Nevada with no irrigation at all except what nature provides? The situation is the bare-looking north side of a wall where I do not want to extend irrigation piping.

A. There is no vine that will make it here without additional irrigation. We average 4 inches of water each year. I have seen it without rain here for over one year. That irrigation might come from a neighbor but it will not survive without some source of water.

We do have wild grape and some other vines that do grow along waterways coming from mountain runoff but they have water and grape roots can grow to depths of 30 or more feet.

The key to avoiding a lack of water is to either store the water in modified plant parts like cactus or have very deep roots that can tap into a water supply that we cannot see.