Scale

December 9, 2017

I’m sending you 2 pics of a disease my Star Jasmine got this summer. It appears these are eggs, when you mash them it’s kind of milky/gooey. They are only laid on the branches/stems, not the leaves. We sprayed all summer with Fungicide 3. Only got worse. What is it?

Picture of scale on star jasmine

This is a classic example of the necessity for proper identification for proper control. You are spraying a fungicide for an insect problem. You have a nice case of waxy scale insects. There are over 150 types of scale insects. They are small, immobile, with no visible legs or antennae, pressed tightly against the plant on which they are feeding. The white waxy outer coating on the waxy scale protects the sucking insect underneath the white coat. As they mature, more and more wax is produced until it eventually covers the entire scale in a thick, white, irregular coat. Wax scale is found on a wide variety of plants including azalea, blueberry, camellia, holly, and others. There is one generation per year with crawlers active in early summer. Using a dormant oil now will help to smother the existing scale insects, and/or using a systemic insecticide in the spring will also work to control them.

December 2014

I have just found the crape myrtle scale on my crape myrtle tree. I hadn’t noticed it when the tree was covered in leaves, but now I see black and white up and down the trunks. What should I be doing now?

If the tree is heavily infested, you can use a soft brush with warm, soapy water and clean it now. Then you can saturate the trunks with a dormant oil to help kill any remaining scale. In late winter/early spring apply Bayer Advanced Tree and Shrub insecticide or a product containing the systemic Imidacloprid.

November 2014

Saw your article recently about Tea Scale on Camellias. Could that also be on Encore Azaleas? We have two Encores’ that have a white scale on many of the branches especially the ones closet to the ground. There are no flowers on the lower part of the Encores. There are small flowers on the top area, but not very many. There are not many new leaves/growth. Any suggestions?

There are numerous types of scale, and some do affect azaleas. The azalea felt scale is white and can build up enough to cause damage. The systemic insecticides will work on these just like on the camellia. Although an organic approach such as dormant oil can be effective, it is hard to get thorough coverage on an evergreen shrub. Remember, once the scale insects die, they usually don’t fall off, but increased vigor should be seen on the plants in the spring.

December 2012

I have a ten year old ficus tree indoors that is oozing and dripping a sticky substance on my floors. I suspect that it is caused by some sort of insect or parasite. It looks like it is very healthy and still putting out new leaves but the sticky stuff is quite a nuisance. Some leaves have small dark scale type things on them. If this is the cause is there anything I can do to rid my plant of them. I've tried spraying with insecticidal soap and removing what I see with rubbing alcohol . Maybe something systemic would work better?

Your ficus tree could have scale, just like the azaleas in the previous question, but ficus trees are also notorious for a process called guttation—where they basically sweat—they have built up too much moisture in their leaves and it has to come out somewhere. It typically occurs when there has been a major change in the plants environment-often when they are moved back indoors in the fall. They ooze excess moisture typically out of the leaf where it is attached on the stem. It is very sticky and it can stain, just like the honeydew that comes from sucking insects. If you determine that insects or scale is the culprit, there is systemic houseplant insecticide that comes in a pellet form of imidacloprid. You put the pellet into the soil and it slowly releases the insecticide and fertilizer into the soil to be absorbed by the root system. They are safe to use indoors.

December 2012

Our azaleas have scale. We cannot get rid of them with regular sprays. I started spraying in early spring, and no matter what, it got no better. What can we do?

One thing to be aware of is that once you kill scale insects, the dead scale don’t go away on the leaves they were feeding on, they are simply dead. You should see increased vigor in the plant and no new signs of scale on other foliage. Scale insects are called “scale” because they form an outer coating that acts as a shield or protection from contact insecticides and other predators. Typically we have to use a systemic insecticide that works from the inside out to control them. Orthene is one that is common, another is Imidacloprid, commonly called Merit or Bayer Advanced tree and shrub insecticide. An older formulation is dormant oil. It really doesn’t contain any chemicals, but it coats the stems and leaves and smothers out the scale. A downside is that you must get thorough coverage, which is difficult with an evergreen shrub.

February 2012

I know it's hard to tell from a photo but my magnolia is sick. The leaves are falling off and the remaining leaves are turning yellow and limbs with no leaves. There appears to be a scaly grayish fungus growing on most limbs. Is there a treatment for his condition?

I can tell by the photo that your tree is sick. The foliage is yellow and there isn't near enough of it. Did you water this past summer? You may have scale insects, but to determine what you have, take a branch in to your local county extension office. As old as your plant is, and as scrawny as it has become, I don't know what kind of turn-around you are going to have, but let’s get it diagnosed and if it is insects, we can handle that, start fertilizing this spring, water and see what happens.

November 2011

I have a mysterious fungus on my bush known as the burning bush. It had little apples on it first, when they fell off the fungus appeared. Do you know what could have caused the fungus to grow?

It is not a fungus but an insect called wax scale. The wax scales are one of the larger scale insects with a white waxy coating which protects the insect. Prune out any branches that are covered in them, and then spray with a dormant oil after all the leaves have fallen off. Dormant oil works by smothering out the insects, so thorough application is necessary. Dormant oil is a good approach on deciduous plants because you can get good coverage. With evergreen plants it is difficult because the leaves are dense which makes coverage more difficult. You can also use a systemic insecticide containing Imadicloprid in late winter. Be aware that once dead, the scale will not fall off the plants, but the large white ones will turn a dull gray color.

December 2011

My ficus tree gets indirect light and is growing well, but it has started dropping a clear, sticky substance on my floors. What's going on and what can I do?

I would say you have one of two things happening. Sucking insects such as scale and mealy bugs could be on the plant, feeding on the foliage, and then releasing a sticky substance called honeydew. Inspect the foliage to see if you see any signs of these insects. If so, you can spray with insecticidal soap or use plant spikes with Imidacloprid in them. The other problem is called guttation. It is almost like sweating. It usually occurs when there are major changes in moisture levels and humidity. The plant loses extra water from the tips of the leaves. The moisture contains natural sugars which can be sticky and can discolor the floor. Make sure you aren’t overwatering.

August 2010

I am having a terrible time this summer with my golden euonymus. I have quite a few of them and don't want to lose them. Something seems to be sucking them dry. I have sprayed them twice with Malathion and it hasn't seemed to help. I have sprayed them with deer repellent too as we have quite a few deer eating them. I am at my wits end as to what to do. Can you please give me some advice?

My guess is you have euonymus scale. These tiny insects feed on the lower and upper leaf surface as well as the stems. It will look like someone poured salt and pepper on the plant. They suck the sap out of the plant and can weaken it considerably. But you should be able to see them. Malathion would give you limited control. A better option would be imidacloprid, commonly sold as Merit, Bayer Advanced Tree and Shrub Insecticide or Ferti-lome® Azalea/Evergreen Food Plus with Systemic. Prune off any heavily infested parts and then treat with the systemic insecticide. You can also wait for fall and spray the plant with a dormant oil, but the oil products must be thoroughly applied to be effective.

October 2005

I bought two camellia plants, planted them as directed, approximately six feet apart. One is dark green, setting blooms, and thriving. The other is, losing leaves, turning yellow, and (here's the kicker) has small white blobs on the stems and leaves. These blobs feel a bit like popped pop corn but definitely have something living inside them. When I squished one, it made a crunch sound and a red liquid oozed out. Really quite "Alien" if you ask me. So that's why I'm asking you. What do you think?

It sounds like scale insects to me. The most common scale insect we have on camellias is the tea scale—but they are small and look almost like grains of salt coating the stems and leaves. Since yours are larger, I would guess probably oyster scale, which has a white waxy feel to it, and can grow quite large. Mealy bugs are soft bodied scales that have a white cottony growth covering them. Scale insects suck the sap out of the plants and with a heavy enough build up, can cause damage, even death over time. Systemic insecticides are quite effective but take time. Dormant oils can be used to smother out the insects, but thorough applications are needed on all parts of the plant—upper and lower surfaces of leaves, stems, etc. Do keep in mind that once the insects have died, they will still be present on the leaves, but you should see new growth that is healthy and the plants should appear more thrifty. Also, if the plants were newly purchased, you might also contact the nursery or garden center and see about an exchange.

December 2009

I have one very lovely, large Japanese Blood Maple and another smaller Japanese Laceleaf Maple. Both are covered with scale. I sprayed both with a dormant oil recommended by my local gardening store twice at a weekly interval. I then treated the soil around the tree trunks as prescribed with Bayer Advanced Tree & Shrub Protect and feed solution. The smaller tree has lost all its leaves and still has the ugly white droppings on its' branches. The larger tree has some leaves curled up and still attached to the branches. So of the limbs look like they may be dead. And this tree also still has the ugly white droppings all over the branches. Both trees are strikingly beautiful and I really would hate to lose either one. Is there any additional action I should take to get and keep these trees healthy?

It is quite possible that you have killed the scale--you definitely treated with the right products. Once scale insects die, they don't fall off and disappear--but they are no longer causing damage. For now, do nothing. Wait until spring and see how the plants leaf out. Then monitor the new growth and twigs for signs of scale. The imidacloprid in the Bayer product you used should give you good protection. Usually one application in the spring can cover you for the year.

November 2008

I have a large ficus tree in my foyer (southern exposure). The tree is over 10 years old, and I have kept it in the house year round for the last few years. In the past couple of months I have noticed that a lot of green leaves are dropping. When I pick up the leaves they are very sticky. Any ideas on what is going on with my tree? I'd like to keep this tree, but at the rate I'm losing leaves it may be bare in the next month or so.

Ficus trees drop leaves easily, especially when there is a change in weather conditions. Keeping them inside year-round, if they are healthy helps to deter leaf dropping, but doesn't always prevent it. Two problems could be causing the stickiness--sucking insects such as scale or a natural phenomenon on ficus called guttation (basically the plant sweating). It all gets down to the fact that plants must get rid of the excess water in their leaves. Normally they do this through their pores called stomates through a process called transpiration during the day. Some plants have other specialized pores called hydathodes which can also excrete sap and you will actually see tiny beads of water forming on the tips of the leaves. It can be quite sticky. The process occurs most frequently during conditions of high humidity when the rate of transpiration is low or when there is a major shift in humidity. Check for insects, because they could also be responsible for the leaf droppage.

April 2005

I have a problem with my 18 year old camellia tree. Usually it has red blossoms in the spring. This year it looks sick and the few blossoms are far from their normal beauty. There is a white covering on the leaves which is probably some sort of disease. I would appreciate any suggestion you have for treating this problem.

I do not think you have a disease but an insect problem. I have seen an abundance of scale this year on everything from hollies to camellias. Scale insects can vary in size from a half inch to the size of a pinhead. On camellias, the most common scale is called tea scale. These insects attach themselves to the leaves and suck the sap out. As they multiply, it can severely impact the plant. Each female deposits from 10 to 15 eggs under the scale shell. They hatch in 7 to 21 days, depending on the weather. The flat, yellow crawlers migrate to the newer growth on the plant and, in 2 or 3 days, attach themselves. At first they secrete thin, white coverings, but shortly afterward they produce great quantities of white threads. As the population builds up, the undersides of the leaves may be covered with this cottony secretion. From 41 to 65 days after hatching, female scales begin to lay eggs. The life cycle is usually completed in 60 to 70 days. The hatching of tea scale nymphs occurs throughout the year, although it is less frequent in cold than in warm weather. If left unchecked, they can build up quite quickly. Use a systemic insecticide such as Di-syston, Bayer Advanced Tree and Shrub insecticide, or try spraying with Orthene. Contact sprays are difficult to control these insects since we have such a heavy network of leaves, and the insects do most of their feeding on the underside of leaves.

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