Simple white paper test will solve many a mite mystery

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Question: I have an Italian cypress tree, which this past summer got some browning in the branches. I saw some webbing in the tree. I used an insecticide on the tree to try to kill any bugs that might be attacking it, but it comes back every year in the summertime. Last year, I used a pesticide that is supposed to kill mites. That didn't work. What do I do?

Answer: Mites are of two general types: those that cause plant damage and those that are predators on mites that cause plant damage. The big problem using miticides to control mites is that it kills both.

In a healthy environment free of dust, the predatory mites will keep the plant damaging mites under control. All we have to do is hose off plants periodically to remove dust, which interferes with the predatory mites chances of keeping the bad guys under control. Using miticides disrupts this balance and frequently the bad guys then go unchecked when they re-infest the sprayed area.

This also can happen when using pesticides like Sevin. Not all mites spin webbing. And the mites that do can either be predatory or the bad guys, so using the webbing as an indicator does not always work.

A better method is the white paper test. Take a letter sized piece of white paper and slap it against a branch that looks suspicious. Look at it carefully for a few moments and see if you can see multitudes of little tiny mites, about the size of a pencil speck, crawling slowly over the surface of the paper.

If you see that, plus see some typical mite damage (usually discoloration), then it is a good indicator you have too many bad guys. So look for both the appearance of damage AND use the paper test before applying these chemicals.

You do not want to get into a cycle of having to apply a pesticide because the good guys are gone. You then take their place at your cost. Also, most spiders also can spin webbing and they can be predacious on mites as well.

Mites typically become a problem during hot weather and if the plant is close to a source of wind-blown dust. Try hosing them down as a first step.

Q: I have a 5-year-old, 15-foot-high Mexican fan palm. When is it proper to prune the fronds, When they are starting to die or completely brown? Also is there any benefit to skinning?

A: In a perfect world you should remove fronds as they die. However, we don't live in a perfect world and many people hire people to prune their palms. So with that in mind, remove as few as possible to make the palm still look good. Try to retain a near circular canopy or at least half round.

Try to do your palm pruning annually so you do not have to take off three years worth "to get your money's worth." You can remove fronds anytime of the year if you are judicious in your frond removal. A good resource for you can be found at http://www.ufei.org/files/pubs/SP0416.pdf.

The most popular reason for skinning palms is appearance. Skinning palms removes the opportunities for insects and other critters to live in the bark of the palm trees. This would include the nasty bark scorpion. Skinning palms removes some protection to the trunk of the tree. For a formal appearance, I would skin the trees. Most palms can be skinned. Do it after the coldest part of the winter has passed.

Q: I have a dwarf orange tree planted a little over a year ago. There have been no oranges on the tree. I have fertilized and I think I've been watering it correctly. The tree appears to be healthy, just no fruit. Any suggestions?

A: A dwarf orange is not much help to me. The subject of oranges is huge. I need to know what type of orange it is and whether it has produced flowers or not and no fruit, or no flowers and no fruit. Varieties vary from early ripening -- about 8 months from bloom -- to late -- up to 16 months from bloom.

There are three main groups: The normal fruited, without navels and with light orange colored flesh; the navel oranges, with a distinct navel development at the end; and blood oranges, with red flesh and juice.

There are about 73 varieties, but United States' production focuses on Valencia, Washington Navel, Hamlin, Parson Brown, Pineapple and Temple. For home gardening there are many more than these six available from nurseries.

Q: I have two pink dwarf oleanders planted in 18-inch clay pots, which have very healthy looking foliage but very few blossoms. One of my "expert" gardener friends says simply that "oleanders don't like pots." Another "expert" says that I'm watering too much. Are either of these guys right or do you have any suggestions that might get me some blossoms?

A: We have dwarf oleanders at the Master Gardener Research Center in containers and they bloom just fine. Make sure the pots will drain. When you water, water them until water runs out the bottom of the container. Fertilizer them once in the spring.

There might be a couple of things you could try. Actually, putting plants in containers and restricting the roots in many cases encourages blooming. If the container is small, you might have to water more often.

Oleanders that are not getting enough water will otherwise look normal but have a very open canopy and not bloom well. They are high water users and love fertilizer and mulch. They like some time between irrigations so that the soil drains and dries out, but will not do their best if the soil dries too much between waterings. Even though they are very drought tolerant, I would treat them more as an oasis plant rather than a desert plant.

You can try using a soil moisture meter that you can buy from the nursery for about $7 and just leave it in the container. Water when the dial is about half way between wet and dry. Do not let it go dry. Next use a fertilizer like Miracle Gro and water it into the soil about once every six to eight weeks.

Next, cover the soil in the container with mulch to help keep the soil moist. About 3 inches would be enough. If oleanders are young, or if they are pruned with a hedge shears, they will not produce any flowers, or at least very few. Don't prune it with a hedge shears contrary to what the landscapers do. They should be pruned with pruning shears, not hedged or gumballed.

Q. I have some insects on my pomegranate tree, never saw them before! I sprayed a strong jet of water on the pomegranate fruits and branches, but the black one looks like a seaplane. The red ones look like a smaller version of the black one. Please tell me how I can destroy those insects.

A: Thank you for the excellent pictures. These are both leaf-footed plant bugs. The black seaplane is the adult. The red seaplane is the nymph or young one. They will attack pomegranates, almonds, pistachios and other plants as well.

They are tough to control with organic pesticides. The closest pesticide to organic that I can recommend is a fruit spray that contains the insecticide called permethrin or any of the pyrethroids. Another pesticide that works is Sevin, provided it has a label for fruit and nut trees. Sevin is a nasty little pesticide that kills bees and the good mites as well as bad insects. This only will be seen in the list of ingredients on the label.

Leaf-footed plant bugs will attack almonds and pistachios first then move to pomegranates later causing fruit drop. They can fly and so are difficult to detect sometimes. Their damage to almonds results in sap coming from immature nuts and in pistachios it results in early nut drop.

If you do apply the pesticides I mention above, watch out for damage from mites to the trees that were sprayed. Mite damage can flare up after using these pesticides, because the good predatory mites are killed off, leaving the bad mites a chance to "take over the town."

Bob Morris is an associate professor with the University of Nevada Cooperative Extension.