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Magnolia scale may not look like much at first glance. Initially, many homeowners don’t even realize they are looking at an insect!

Magnolia scale may look innocuous enough, but they can be deadly to magnolia trees. Luckily, magnolia scale can be effectively treated during your annual lawn maintenance.

Magnolia Scale Life Cycle

There are two main species of scale: armored (hard body) and non-armored (soft body).

Magnolia scale is a soft body insect, which can make the process of tree maintenance treatment slightly easier because this type of scale is more vulnerable.

However, it is important to properly identify the pest as early as possible for treatment to have maximum effect. To help, here is a brief overview of the magnolia scale life cycle.

Winter: scale goes dormant.

During the winter season, magnolia scale goes dormant. The insects typically spend the winter in nymph form encased in soft protective wax on the undersides of tree leaves and branches.

Spring: mating and incubation.

In the spring, the adults emerge and mate. The male dies off and the female begins to incubate the young as eggs she lays right underneath her own body.

Summer and fall: birth and feeding.

The adult female covers the eggs with her body until the live young emerge. The young at this stage are called “crawlers.” But the young crawlers only crawl around for as long as it takes to locate a suitable place to sink their sharp mouth parts into the tree branches and start sucking the sap right out of them.

By this time, the cold season is rolling in again, and the now-stationary crawlers enter the nymph stage for the winter right where they sit. Then in the spring the whole life cycle will start all over again.

How to Spot Magnolia Scale

The first thing to know about magnolia scale is that it doesn’t behave like a typical insect. It only moves during spring when adults mate and crawlers are born. Then it stays immobile for the remainder of its life cycle.

For this reason, many homeowners who schedule tree maintenance initially report that their magnolia trees appear to be growing “mold” or have an “ant infestation.”

Magnolia scale often does look a lot like mold or mildew once it settles in to feed on tree branches. It is bumpy and white with a waxy, semi-soft appearance that looks like nothing so much as the early stages of mold rot.

But inside and underneath this “mold,” the now-immobile feeding crawlers are busy feeding on the amino acids in the tree sap. Along with the amino acids they need, the crawlers take in plenty of sugars they don’t need. So they discard the carbohydrate-laden sugar in the form of a sticky substance called “honeydew.” This honeydew in turn attracts ants, wasps, flies, bees and molds that recognize a feast when they see it.

For this reason, sometimes the first indication of a magnolia scale infestation is the honeydew itself. This is especially the case if the infested tree overhands a deck, set of patio furniture, vehicle or walkway. Honeydew is incredibly sticky and corrosive. It will turn anything it lands on sticky. It stains and is very hard to remove.

The presence of honeydew is confirmation of a magnolia scale infestation nearby.

When to Treat Infested Trees for Magnolia Scale

While healthy magnolia trees can generally withstand small, localized attacks of magnolia scale, these pests generally do not go away on their own. Over time, undetected and untreated magnolia scale can kill a tree by draining away its nutrient supply.

Luckily, there are a number of insecticide products that are effective against magnolia scale if they are applied correctly at the right time.

Here, learning about the magnolia scale life cycle is key to successfully terminating an infestation.

The crawler stage (whether mobile or immobile) is the time in the life cycle when magnolia scale are most vulnerable. The adult females give birth in late summer – anywhere from July to September depending on where you live. So this is generally the best time to apply insecticide to treat magnolia scale.

How to Treat Infested Trees for Magnolia Scale

The optimal treatment approach will maximize damage to magnolia scale while limiting damage of surrounding foliage and beneficial insect life.

Here, it is vital to select a lawn maintenance professional to apply treatment to avoid harming nearby lawns, shrubs and unaffected trees.

The first step is to identify the scope of the infestation and the part of the life cycle the scale is currently in.

Summer and fall treatment.

For a small-scale active infestation, it may be possible to simply prune back the affected tree branches and treat just the immediate surrounding branches to ensure it does not spread.

For large-scale infestation limited to one tree or affecting multiple trees, spray insecticides containing horticultural oils and insecticidal soaps can effectively treat magnolia scale in the crawler stage.

Winter and early spring treatment.

Once magnolia scale has entered the dormant stage, treatment requires a different approach.

There is a dormant oil product that can be applied directly to the dormant scale that must be applied before the bud open up in spring, which can happen as early as March in some areas.

Systemic insecticide products can be used to treat the soil surrounding the tree itself. When applied during the winter dormant period, these insecticides will have time to be absorbed into the tree and taken into the sap so it will kill the crawlers when they emerge in the spring.

By understanding what a magnolia scale infestation looks like at different times of the year, it is possible to make a positive identification earlier in the life cycle when the scale are at their most vulnerable.

By identifying magnolia scale accurately and early, a number of effective tree maintenance treatments exist to eliminate infestation and restore tree health.

Rhizosphaera needle cast is a type of fungus that primarily affects spruce trees. The term Rhizosphaera refers to the species of invading fungus, while the term needle cast refers to how the disease progresses as the spruce “casts off” infected needles.

Not all spruce varietals are susceptible to Rhizosphaera needle cast disease, which can aid in landscaping decisions. Colorado blue spruce, Oriental spruce and white spruce are known to be susceptible to this fungal infection, while Norway and red spruce are more resistant.

If you are caring for spruce trees at your home or workplace, it is important to learn the signs of needle cast infestation. The earlier you catch a fungus like Rhizosphaera, the more successful treatment is likely to be.

In this post, learn what Rhizosphaera needle cast is, what it looks like, where it comes from, treatment options and prevention tips.

What Is Rhizosphaera?

The term Rhizosphaera actually represents more than one fungal species, although the species R. kalkhoffii is most frequently implicated in spruce infestations.

This type of fungal infestation is actually rather common in spruce trees, especially among those that are planted in areas where they are not a native species. Wet, cool conditions can speed up and worsen an infestation.

What Does Needle Cast Disease Look Like?

Needle cast disease can take some time to become evident. The amount of stress the tree is under can shorten the time period to less than one season. Evergreen trees like the spruce won’t replace shed needles, so over time as the disease progresses, the symptoms will become more evident as the tree grows increasingly bare.

In general, it takes 12 to 15 months before symptoms become easy to detect. The main symptoms include the following:

– While new needles grow in green, older needles become discolored, often turning brown or yellow.
– When observed closely, needles can be seen to have tiny black dots along their length that are fungal spores (black dots are diseased; white dots are normal).
– Needles that have grown discolored will be shed in the fall and will not regrow.
– As the infestation progresses, the tree will look increasingly bare or even “see through.”
– The most typical damage pattern begins with infestation on the lower limbs that consistently moves upward until only the topmost crown of needles remains.
– After a majority of needles have become infected, this can then cause the branch to die off.

What Causes an Infestation?

Unfortunately, the Rhizosphaera spores are quite difficult to kill even through the harsh winter season, where they overwinter on living or dead needles. When spring arrives and the snow melts, splashing water can infest nearby trees.

The overall health of the tree can make it less or more susceptible to an infestation. Trees that are already stressed out from lack of water or nutrients, a difficult winter, poor husbandry or other health issues may be more apt to become infected.

While the fungus prefers young needles, it will also infect older needles if the need arises.

What Treatment Options Exist?

For severely infected trees, especially if they are smaller spruce that hold little value to your property, the best option is often a simple tree removal.

Several fungicides have proven to be effective to save spruce infected with Rhizosphaera. Fungicide chemicals that contain chlorothalonil or copper as an active ingredient are typically the most effective.

It is important to understand that there is no “cure” for Rhizosphaera and re-infection can occur at any time. The goal of fungicide treatment is not to cure the tree, but to prevent further infection or spread of Rhizosphaera.

The optimal time for treatment is in the spring during new needle growth. It is recommended to space fungicide treatments three to four weeks apart, continuing throughout the spring growing period or the wet season as applicable.

Fungicide should be sprayed over the entire tree. It is very important to ensure all needles receive the fungicide treatment, which can become more challenging with very large spruce.

Is There Any Way to Prevent It?

The hands-down best way to prevent a Rhizosphaera infestation is to plant a resistant varietal of spruce such as Norway or red spruce. However, be aware that even these spruce varietals can become infected under the right conditions.

Always take care to only plant non-infected spruce and to avoid planting any new trees near already infected trees. When infected branches or needles fall, take care to dispose of them by burning (if allowed in your area) hot composting or burying.

Colorado blue spruce is the most vulnerable. But any spruce varietal that is planted in sub-optimal conditions or has ongoing health issues is a potential candidate for Rhizosphaera infestation.

One key to preventing a Rhizosphaera infestation is to practice proper husbandry. These tips can help to prevent fungal invasion:

– Be sure your trees are pruned properly to facilitate maximum air circulation – air is not a friend to Rhizosphaera, which thrives in damp, cool, close conditions.
– Keep proper distance between trees when planted to avoid overlap as they grow.
– Keep your tree base properly weeded and mulch only up to four inches depth and up to two inches away from the trunk itself to permit proper airflow.
– Do not use sprinklers that spray near spruce (soaker hoses are a much safer option).
– Avoid pruning during the wet season to prevent fungal spread.
– Have a preventative fungicide treatment done annually to protect new needle growth (this can be helpful even on previously infected trees).

What to Do If You Suspect Rhizosphaera

The first step is to have your trees evaluated by a tree care professional. We will come to your site to evaluate your spruce and make recommendations for removal and/or treatment.

We will then provide you with a free, no-obligation quote for tree removal or the treatment option of your choice.