Garden Answers
Fruit Trees
Wormy apples?
What to do for Cherry Fruit Flies?
Peach tree insecticide treatments?
Watering in Winter?
Fertilizing fruit trees?
When to use dormant oil spray?
Will Almond and Pecan trees grow here?
I can’t find Diazinon anymore. What should I use?
What can I do to stop the damage from blister rust?
What is this orange, oozing blob on my cherry tree?
What kind of fertilizer should be used on peach trees and when?
Question: I've got wormy apple trees
and I'm sick of not getting any fruit from them. What can I
do?
Answer: Coddling Moth (wormy apples) is actually an
epidemic there in the Grand Valley. It's so prevalent, that
without seasonal treatment you WILL get wormy apples. Treatment
is a must.
The first thing you can do to increase the chances of having
a good crop, is to thin your apples by hand. Apples usually
bloom in clusters of 4-5 flowers which bear about 2-3 fruits
each. When they're about the size of a marble, pinch off each
extra fruit from a cluster leaving the biggest one in the cluster.
By thinning to one fruit per blossom cluster, you're exposing
the fruit for better coverage of the insecticides you apply.
When fruits are too close together they tend to rub against
one another often rubbing off insecticides and allow the coddling
moth to take advantage of easy access. This may sound drastic,
but this insect is SO widespread here, it only needs a tiny
opening to attack your apples.
There are other advantages to thinning your fruit. Besides
helping with insecticide coverage, thinning your apples enables
those you do have to grow into huge, gorgeous, prize-winning
fruit you'll be proud of and happy to eat! Another advantage
is that by thinning your crop, you help even out what the tree
bears each year. Lots of times you'll find that one year you'll
have a bumper crop; your tree will be so loaded its limbs are
drooping toward the ground. Yet the following year you'll find
a much lighter crop load and wonder what's happened. Thinning
fruit helps break this cycle and helps keep your tree from breakage
that can occur when it's too full of fruit.
The flip side of caring for your apple trees involves spraying.
It is extremely important, and necessary if you want to avoid
losing your entire crop to these nasty coddling moths. Beginning
when the fruit is the size of a marble (and hopefully just after
you've thinned them), spray EVERY WEEK TO 10 DAYS without fail
until the fruit is ready to be picked. I know it sounds extreme,
but this guy is determined and if you miss spraying he'll move
right in. Rotating sprays is best. Use Hi-Yield 38 Plus, Sevin, or
Spinosad, alternating sprays each time. You don't need to have
all three sprays, just choose two and then USE THEM! The most
difficult time comes once the fruit's looking large, lush, and
almost ready to pick. That's when a lot of folks are tired of
it all and decide to quit spraying. It's certainly temping.
Don't be deceived! Stick with your spraying schedule right up
to the day you pick those apples. Coddling moth really is epidemic
here, and they will happily move into your fruit if given the
slightest opportunity.
Having said all that, even if you follow your thinning and
spraying schedules to the tee, you need to expect some wormy
apples. There are so many of these guys, it's pretty much impossible
to get 100% coverage 100% of the time and they will show up
in a few of your apples.
If all of this is more than you want to deal with on an annual
basis, you might want to consider removing your apple tree.
Fruit tree growers are obligated to properly care for their
trees, to help prevent the spread of insect and disease problems
into the orchards. If you would rather not have this obligation,
you can receive a certificate good toward the purchase of a
non-fruiting tree or shrub to replace the fruit trees you remove.
For information about this program, please contact Karen at
255-7121 BEFORE you cut down your trees.
Back to the top.
Question: The worms seem to get all
the cherries on my tree before I can. What can I do?
Answer: This is the Western Cherry Fruit Fly or Cherry
Maggot which really didn't show up in Western Colorado until
the year 2000. This insect is a small fly that overwinters in
the soil as a pupa beneath the cherry trees. It emerges in the
Spring and lays its eggs in the developing fruit of cherry trees.
The larva (maggots) hatch out and feed on the ripening fruit.
Left untreated, essentially every cherry on the tree will be
infested with these disgusting creatures.
The most impotant thing in controlling this insect is timing
of the sprays. Sprays should start about May 20 and be repeated
every seven to ten days until harvest. We recommend using Spinosad,
Sevin, and Malathion. One thing that can help people is that
infested fruit tends to ripen faster than clean fruit. Any infested
fruit should be destroyed or thrown into the trash to cut down
the problem for next year.
Like Coddling Moth, this is an insect that people really should
be conscientious about controlling for the sake of the commercial
growers in western Colorado. If a homeowner is unwilling to
keep this spray schedule, they should seriously consider removal
of the tree, or at least removal of the fruit every year to
make it a little easier on the commercial growers and the responsible
homeowners willing to do the sprays.
Back to the top.
Question: I have some peach trees on
my property and have treated them with different insecticides
in the past, but it seems that each year I hear something different.
What am I supposed to be doing now?
Answer: It's a little late to be starting treatment,
but it's much better than doing nothing. The peach tree borer
attacks members of the genus Prunus that set a "stone type"
fruit. This would include peaches, plums, cherries, and apricots.
It can also affect their ornamental relatives such as cistena
plum, pink flowering almond, purple leaf plums, European bird
cherries, schubert chokecherry, flowering cherries, double flowering
plum, Nanking cherries, and more. Basically that means that
each of these plants has the potential for getting peach tree
borer, and to be sure they don't, each should be treated to
prevent it.
What this borer does is tunnel around under the bark like other
shade tree borers, but it does it low down on the tree near
ground level. The best treatment is actually a drench around
the tree (use a watering can or a bucket) of Permethrin. Timing
is important, but with this guy, the tree should be drenched
June 20, July 10, and again on July 30. Wet the bottom 6"-8"
of the trunk and soak the ground immediately around the trunk.
You can use the 2.5% concentrate of Permethrin according to
label directions. The 38% concentrate is NOT labeled for use
on edibles. You can use it on ornamentals at 4 tsp./gallon and
apply it June 20 and again July 20.
If you notice a gummy, jelly-like ooze around the base of the
tree which indicates the presence of peach tree borer, you've
missed the window of opportunity to drench for them. However,
you can get some mothballs made of paradichlorobenzene (PDB)
to fumigate these guys out. Crush the balls into a coarse powder.
Dig a shallow trench an inch or two deep, and a couple of inches
away from the trunk of the tree (never put the crystals up against
the tree - it can hurt the tree). Sprinkle the crystals lightly
(it doesn't take much) into the trench, and cover them with
soil, mounding up around the trunk 5"-6", and water
the soil to seal in the fumes. This isn't as effective as the
drench, but it's better than doing nothing. If this is too confusing,
we do have a hand-out with instructions we give folks who come
in looking for insecticides to treat their peach tree borer.
Hope this helps.
Back to the top.
Question: A friend recently told me
that she "deep waters" her trees and shrubs once a
month through the winter. I've never done that before (I'm new
here) and thought that the rain and snow we get is enough. Now
I'm not sure what I'm supposed to do!
Answer: Your friend's got the right idea. Most folks
have been using their irrigation water to keep their plants
happy, and once that's turned off for the year, they kind of
leave things to nature. Though we've had some good rain this
Fall, generally we don't get enough precipitation (in rain or
snow) through the winter months to give plants sufficient moisture.
That's where "deep watering" comes in. It's an individualized
thing, but basically you want to water trees and shrubs deeply
and infrequently (November through February), which means every
three to six weeks depending upon the weather. What you want
to do is to get the moisture down deeper into the soil without
getting it waterlogged. I usually just screw on a round pattern
sprinkler on the end of my hose and place it out near the tree.
Turn on the water so it covers a circle 10' to 20' across, depending
upon your tree (the bigger the tree, the bigger the area to
water). I'll go inside and set the oven timer for an hour and
let the water run. When the timer goes off, I'll move it around
to the next spot that needs soaking. Be sure you only do this
on a sunny afternoon when the air temperature is above freezing
(which is what most of our winter days are like). Hope this
helps.
Back to the top.
Question: What kind of fertilizer do my peach trees need and when should any applications be made?
Answer: We would recommend that you fertilize your fruit trees only in the spring. There are a number of different fertilizers that you could use, but the main need of the plant would be for Nitrogen. There are different forms of Nitrogen, some fast-release and some slower. Fast-release forms of Nitrogen like
Ammonium, Urea and Nitrate are available quickly, but they don't last as long. You'd want to apply something like that two or even three times during the spring. Slow release forms of Nitrogen last longer and would only have to be applied once or twice.
The product we recommend most often is our own Bookcliff Gardens Choice Professional Turf Food. It's a high nitrogen fertilizer (25%) that's in a slow release form. It also has a little Phosphorus and Potassium (3% of each) and some Iron which I think is also important. Apply it the latter part of April after you get your irrigation water. Apply it about twice as heavily as the bag recommends, scattered well around the tree out to the drip line. Don't put big piles up against or around the tree, as this can cause damage. Water the entire area well after putting down the fertilizer. I've done this in my yard lots of times, though I usually just do it the one time each year.
Back to the top.
Question: Is it about time to spray with
dormant oil?
Answer: As with most gardening tasks, I can't give you
a specific date to spray dormant oil. It takes careful observation
to find the right time. In general, however, the time to spray
is from mid-February to mid-March, but it really depends on
the weather. If temperatures are warm enough to encourage buds
to open and reveal some green growth, it's too late to spray.
The spray would damage the tender buds. But if those buds are
closed up tight, go ahead and spray.
If you're unfamiliar with dormant oil, let me share with you
this helpful tool for controlling insects and disease in your
yard. Dormant oil is a great broad-spectrum treatment for problems
that overwinter on the stems of plants. I'm talking about our
mortal enemies: aphids, spider mites, some caterpillars, powdery
mildew, leaf spots, and a host of others. If you had these problems
last year, you can minimize the problem for this year with a
little pre-emptive strike of dormant oil. Now, dormant oil won't
eradicate the problem, but it will make it less noticeable or
give those ladybugs a fighting chance against aphids.
Besides making pest and disease problems more manageable, dormant
oil is a popular choice because it's nontoxic. Dormant oil is
a high-grade mineral oil. When spayed on stems, it coats and
suffocates insects, eggs, or spores while being safe for children,
birds, and pets.
We have a new product this year called Bonide Dormant Oil Plus
Lime Sulfur. This product combines two organic pesticides that
help give great control of lots of pest problems, especially
powdery mildew and spider mites. If you think you need this
added boost, come in and talk to one of our nursery professionals.
We'll recommend the right chemical for the job.
Back to the top.
Question: I’m interested in planting Almond and Pecan trees. Will they grow here?
Answer: Both Almond and Pecan trees will grow here in the valley. Almonds are actually closely related to Peaches so any place Peach trees will grow, an Almond will too. The difference is that Almond trees bloom very early in the spring (usually even before Apricots). If the flowers freeze, you’ll lose the fruit for that season. Another thing you should know about Almonds is that most of them require another variety for pollinization (which is needed to produce the fruit). There is a variety called ‘Hall’s Hardy’ which is very cold tolerant and self-fertile, but it produces very hard-shelled nuts that require a hammer to crack open. We used to sell a variety called ‘All-In-One’ which bears soft-shelled nuts and was self-fertile.
While Pecans will grow here, their nut production can be somewhat spotty. As with the Almonds, you will need two varieties to get fruit, one an early pollen-shedding variety and the other a late pollen-shedding variety. Also, Pecans can take up to fifteen years to begin producing nuts whereas Almonds will start producing almost immediately. Eventually, Pecans will grow into a very large tree (40’-60’), so be sure to plant them in an area that has enough room for them to grow.
Back to the top.
Question: I have apple trees in my yard and have sprayed them with Diazinon for the past couple of years so they don’t get worms in the fruit. It’s worked really well for me, but I can’t find Diazinon anymore. What should I use?
Answer: The reason you can’t find Diazinon anymore is because it was taken off the market in January of 2004. I tell folks now to use a rotation of two or three different sprays. As with the Diazinon, begin when your fruit is the size of a marble (usually late May to mid June) and spray every week to ten days WITHOUT FAIL until the fruit is ready to be picked. Don’t be deceived by nice looking fruit and stop spraying before your apples are ready to harvest. They really do need constant coverage. Look for Permethrin 2.5% (do NOT use the 38% Permethrin as it’s NOT labeled for edible plants), Sevin or Spinosad. Alternate sprays each week. You don’t have to have all three of these, but do choose two and use them FAITHFULLY!
Back to the top.
Question: I live on Battlement Mesa and have a Dwarf Yellow Delicious Apple tree that’s about three years old. Most of its leaves have this brownish rust on the underside that dries them out. At first they turn yellow and begin to curl, then the rust appears and the leaves turn dry and brittle. The stem of a trunk (approximately 2" diameter) doesn't appear to be scaling or sloughing. The locals tell me I have blister rust. From what I have described, what can I do to stop the damage and save the tree?
Answer: I'm pretty sure that you don't have a Blister Rust on your Apple tree. Rusts are pretty rare here in the valleys of Western Colorado. Rusts thrive in a high humidity environment and we're just too dry to have much of a problem with them. Having said that, of course it's possible that you might have Rust. We can see problems with Rust diseases when we artificially raise the humidity by our watering practices or have some unusually wet weather, and sometimes it just shows up for no reason that we can see.
I really need to see a sample of the tree to tell you whether it's Rust or something else. A rusty bronzing of the foliage is not Rust. Most Rust diseases form "pustules" on the underside of the leaf. These are small spots that usually protrude slightly and look velvety. Many Rusts have pustules that are bright orange though others can be olive green, brown or black.
What you're describing can be due to watering problems, Powdery Mildew, Spider Mites, or any number of other causes. Bring in a sample, I'm sure that we can give you a better idea of what's going on.
Back to the top.
Question: I recently looked at my cherry tree and discovered an orange-colored, oozing blob on it where I cut a branch off a year or two ago. Is this something that I should be worried about?
Answer: Well, there may be a problem brewing or there may not. Members of the genus Prunus (like your cherry) are “bleeders.” That is, they tend to bleed a lot of sap where there’s a wound whether that wound is new or old. That orange blob is a big gob of sap the tree is exuding and it may just be related to the fact that a branch was cut off at that spot sometime in the past. If that’s the case, there’s nothing to worry about, the gum will stop flowing in time and harden and the tree will continue to keep on growing. People often worry that their tree is going to “bleed” to death; that doesn’t happen, they’re different from people.
The other alternative is that something is wrong and this gum pocket is a warning sign. There are two possibilities I can think of. The first and most common is that your tree has a borer called a Peach Tree Borer or Crown Borer. This insect is epidemic here in the valley on all stone fruit type plants like Peaches, Plums, Cherries and Apricots as well as their ornamental relatives. They tunnel around under the bark but are usually only found down near the ground. The gum pocket is just a stress reaction of the tree to the damage going on down below.
Take a look at the trunk at ground level or even an inch or two below ground level. If you have the borer, you’ll usually see loose, cracking and peeling bark with more of the gummy, jelly-like ooze. If you see any of that, there are some effective drench treatments you can apply to prevent this little monster from bothering your tree, but we’re at the wrong time of the year to do that. Those drenches should be applied in late June through July. You could crush up some mothballs and sprinkle them lightly around the trunk, making sure they don’t touch the trunk, but that sometimes doesn’t work. If the tree is looking healthy, I’d probably wait until June to start treating the tree. Come on by the nursery, we have a sheet that tells you what to do and when.
The second possibility is that you have a fungal disease called Cytospora canker. Cytospora is always a problem on trees that are weak and under stress for one reason or another, usually Peach Tree Borer problems. Treating the borer will allow the tree to heal itself and get back on its feet. A healthy tree will usually be able to fight off the disease by itself. Unfortunately, we don’t have any effective fungicides that will help you with this problem. Concentrate on getting that tree as happy and healthy as you can.
Back to the top.
Question: I recently bought a home on Orchard Mesa that has a couple of mature peach trees. Is there a way of identifying them? Also, what kind of fertilizer is required and when should any applications be made?
Answer: It can be hard to identify a particular variety of peach, but it would be done by watching for when the fruit ripens. Probably the best way for you to identify what variety you have would be for you to take one by the Extension office at the Fairgrounds and see if they could help you.
We would recommend that you fertilize your trees only in the spring. There are a number of different fertilizers that you could use, but the main need of the plant would be for Nitrogen. There are different forms of Nitrogen, some fast-release and some slower. Fast-release forms of Nitrogen like Ammonium, Urea and Nitrate are available quickly, but they don't last as long. You'd want to apply something like that two or even three times during the spring. Slow release forms of Nitrogen last longer and would only have to be applied once or twice.
The product we recommend most often is our own Bookcliff Gardens Choice Professional Turf Food. It's a high nitrogen fertilizer (25%) that's in a slow release form. It also has a little Phosphorus and Potassium (3% of each) and some Iron which I think is also important. Apply it the latter part of April after you get your irrigation water. Apply it about twice as heavily as the bag recommends, scattered well around the tree out to the drip line. Don't put big piles up against or around the tree, as this can cause damage. Water the entire area well after putting down the fertilizer. I've done this in my yard lots of times, though I usually just do it the one time each year.
Back to the top.
Bookcliff Gardens
(970) 242-7766
755 26 Road (North 1st at I-70) • Grand Junction, Colorado 81506
Ask the Expert
©2008, Bookcliff Gardens
