insect

Arbor-wellness: Spruce Spider Mite

Spruce trees are one of the most popular trees in the Pacific Northwest. Seeing conifer trees with shades of green, gray and blue-green in the winter is refreshing and brightens the otherwise dull winter.  Spruce trees are common to this area and very hardy trees. The blue spruce – native to Colorado – is a favorite on public and private landscapes.

We do see a particular problem on these trees that can cause the tree to decline fairly rapidly. The spruce spider mite is a very fast reproducing insect that will quickly harm spruce trees and most other conifers if not treated. They feed on the needles and create a stippling effect, eventually turning the leave brown as they die off. We are seeing more of this pest the last few seasons, so it is important to pay closer attention to spruces, arborvitae and firs in particular.

Treatments done early can prevent damage most of the season, but if damage is noticed in the fall, it is important to treat quickly as that is when they do the most damage.

The needles on my spruce tree are turning bronze colored and falling, what is wrong?

This is most likely being caused by spruce spider mite, a fast reproducing insect that feeds on the needles of spruce trees and other conifers. They feed by “rasping” the needle with specialized mouth parts and the needle starts to turn yellowish, the bronzy as it dies. When they turn bronze like that, it is a sign that you have a fairly bad infestation. With spruce spider mite, you might also notice some light webbing too.

Can my spruce be saved?

At this point, it is imperative to treat quickly to with a fast-acting treatment to get the problem under control. But yes, in most cases we can save the tree.

What other trees do they affect?

They will feed on most conifer trees, but mostly on spruce trees, fir trees, and arborvitae. They are most active in the cool season, so damage is done in the spring and again the fall. (Often the summer is when you notice the damage though because the weakened tree has a harder time with the stress of summer heat.

 When do I treat them?

When you see damage in the summer or fall, it is important to treat them right away with a fast-acting product. You should also avoid spraying products on the tree during this time, because you will harm the predatory insects that feed on spider mites. Those are the good guys we want to keep. In the fall or early spring, we can do a proactive treatment that prevents the population from building up too high. This allows the tree to recover more quickly. Without any treatments, populations can build so high they may eventually kill the tree.

What else should I know?

Spruce spider mites are a cool season spider mite, but there are warm season mites that feed on other tree types and do most of their damage in the summer. Your Arborwell arborist knows what to look for and can help spot problems before they get too bad. Remember too that keeping trees healthy helps prevent trees from becoming stressed, which allows insects to attack trees more easily. Proper feeding and proper watering will go a long way to reducing spider mite problems.

If you are concerned about spider mites on your Spruce (or other) trees, fill out the form below to contact your Arborwell arborist to help you solve this problem for you.

insect, plant health care, spider mite, Spruce

Arbor-wellness: Pine Bark Adelgid

Pine trees are common in many of our landscapes. They are decently drought tolerant and bring a little bit of the forest look into our Southern California beach climate. One of the most common pests we find on some of them is a little white cottony pest called Pine Bark Adelgid. This creature is usually found on the bark of several of the pine species we find here. In small numbers they don’t do much damage, but when their population gets high enough, they can weaken a pine tree significantly. Weakened pines are then subject to other insects and diseases that are lethal to them.

When we see a population growing on one or more trees, we usually recommend treating them for a few seasons to reduce the population. If the trees are not healthy, we will also make a recommendation to improve their health. If the tree is otherwise healthy, we won’t have to treat for at least several years. We often use alternate treatments besides spraying for them, which gets better results and we don’t harm the good guys as much.

Adelgids are making a comeback.

One insect that is not talked about much but can become very problematic is a tiny, fuzzy white insect called Adelgid. They feed almost exclusively on conifers, but each type is fairly limited in the number of different tree types it feeds on. They feed on the sap and weaken the trees. When populations are high enough, they will eventually kill the tree, especially hemlocks.

Hemlock Woolly Adelgid

These feed on the needles and small twigs of hemlock tree, forming masses of white cottony spots on hemlocks. They are most prevalent on Eastern hemlock trees and are less of a problem on the Western varieties of this tree.  

Pine Bark Adelgid

Most common on thin barked pine trees. They tend to cover the bark close to where branches extend from the trunk, but can fill the entire trunk when the population builds up, creating an almost snow-like affect on the trunk. These adelgids weaken the tree when present in large numbers, but are often not fatal. They tend to favor stressed tress, so maintaining healthy pine trees goes a long way to keeping this insect in check.

Cooley Spruce Gall Adelgid

They are found on Colorado blue spruce, Douglas fir, and Englemann and Sitka spruce. They feed at the tips of small twigs and form a unique looking gall. Once they mature and leave, the gall turns brown and dies, leaving tips of the tree looking unsightly. Rarely do they need treatment, but can be warranted when the population is high.

Balsam Woolly Adelgid

This tiny sucking insect was introduced to North America from Europe. It is a serious pest of true firs in forests and landscape, and in Christmas tree production. Balsam woolly adelgid feeds on the stems of true firs. White or grayish masses of eggs or newly hatched purplish-black insects can be found on the twigs, branches, or trunk. Heavy adelgid infestations may cover the entire trunk. The feeding insects cause the tree to form swollen, knob like areas at nodes and tips of infested branches. Adelgid infestations weaken trees, cause foliage to become sparse, and can kill trees. This is a serious pest in the forest and common on most firs in landscaped areas. Balsam fir and subalpine fir are particularly susceptible. There are two to four generations per year.

We can help you determine if adelgids are a problem on your hemlocks, pines, firs or other conifers.

Fill out the form below to contact your Arborwell arborist to schedule an inspection.

Adelgid, Bark, insect, Pine, Pine Bark Adelgid

Arbor-wellness: Diamond Scale

Diamond scale is a fungal disease found exclusively on certain palm trees. The name causes a bit of confusion, as the term “scale” usually refers to scale insects. Diamond Scale is an actual fungal disease that is normally a relatively mild disease that rarely causes the death of the palm. However, it does make infected palms look unsightly and predisposes them to other diseases which may be lethal. It derives its name from its characteristic diamond-shaped fruiting bodies.

Diamond scale attacks primarily the California fan palm in coastal areas and in inland areas subject to coastal influence. The drier climate areas of California rarely see it. It does warrant treatment when found in coastal areas, because it us usually indicative of a palm in poor health. Besides treating for the disease, keeping palms healthy and vigorous helps keep the disease in check.

I have black odd shaped spots on my fan palm, what is that?

That is a disease called Black Diamond Scale”. It is common on California fan palms in areas with coastal influence.

Will it kill my palm?

It won’t kill your palm outright, but it weakens the palm and makes is susceptible to other diseases that may be fatal. If your palm is not growing fast enough, it will build up in large numbers on old fronds, making it quite unsightly.

Will it spread to my other palms?

It seems to only affect California fan palms and palms that are crosses between Mexican fan palm and California fan palms. The pure Mexican fan palm and most other species aren’t affected by it.

What should I do about it?

There are several steps that are important to take:

First consider pruning the older fronds out annually. This lessens the problem, but be sure to dispose of the fronds off site and don’t prune healthy palms with the same equipment unless you sterilize the equipment first.

Second, make sure the palm is growing adequately. Palm are heavy feeders and should be fertilized with specialty fertilizer twice a year in most cases. Also make sure there is adequate drainage and that it is properly watered.

Lastly, treatment should be considered on a regular basis until the palm recovers and is healthy. Your Arborwell Arborist can recommend a program to help your palms stay healthy and disease free.

Fill out the form below to get in contact with our team!

diamond scale, fungi, insect, palm

Closeup of Psyllids

Arbor-wellness: Psyllids

When large trees lose their leaves in mid-summer, we tend to panic, and often for good reason. We tend to think of water problems or diseases as the main cause, but sometimes it may be a small insect that is hard to spot. Psyllids are small insects that suck plant juices and excrete sticky honeydew on which blackish sooty mold grows. Some species secrete pale or white wax masses, pellets, strands, or coverings called lerps. They affect many species of trees in our region, but the most common are Eucalyptus, peppertree, citrus, acacia, laurel and tipu or rosewood.

My eucalyptus trees are losing lots of leaves, what could be wrong?

There are several reasons why eucalyptus leaves drop their leaves in large amounts. If you see small, whitish “caps” on the leaves, this is a type of “psyllid” called “redgum lerp psyllid”. This is one many psyllid types that are common in our region.

What other damage can psyllids cause?

High psyllid populations reduce plant growth and cause tip damage, discoloration or dieback. Certain species can cause premature leaf drop. Excessive honeydew creates a sticky mess on cars and surfaces below trees.

Do psyllids damage other trees in my landscape?

There are over 160 psyllid species that occurs on landscape plants in California. Each kind of psyllid feeds only on one plant species or one closely related group of plants. Most psyllids native to California are relatively uncommon and rarely become pests. But some can cause extensive damage. These are generally psyllids that have become pests on trees that are originally from other countries. The most important tree damaging psyllids occur on acacia, eucalyptus, olive, peppertree, laurel and citrus.

I’ve heard about citrus trees dying or being taken out, is this the problem with them?

Well, sort of. A relatively new psyllid pest (Asian citrus psyllid) has been introduced into parts of California. The insect itself doesn’t kill citrus trees, but it can introduce a disease called “Citrus Greening” that is essentially fatal to them. If allowed to become widespread, it is feared the California citrus industry will be wiped out. Currently, the agencies involved are heavily involved in scouting, insect control and plant removal efforts in regions that are most affected. Being vigilant about scouting and controlling this pest when found is very critical.

What can I do?

Your Arborwell arborist can identify locations where Asian citrus psyllid, Redgum lerp psyllid (or other types) are doing the most damage and recommend a treatment program to recover your trees and to keep them healthy. They can also recommend a proper plan for citrus trees on your property if you are close to an area affected by Asian citrus psyllid.

Fill out the form below to contact an Arborwell arborist and find out more about Psyllids and what we recommend for preventing damage and for helping trees recover if they have been attacked by high populations of Psyllids.

arborist, eucalyptus, insect, preventative tree care, psyllids, tree care

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