Probably not. Spraying will kill the natural predators. That is why moving to shade works because the natural predators thrive in shade but not in sun.

Spraying with horticultural soap will work but it will not have the long term effect you desire. Some azaleas were just never meant to be planted in sun.

The following azalea cultivars have resistance to azalea lace bug: Dawn,´ ´Pink Star,´ ´Ereka,´ ´Cavalier,´ ´Pink Fancy,´ ´Dram,´ ´Seigei,´ ´Macrantha,´ ´Salmon Pink,´ ´Elsie Lee,´ ´Red Wing,´ Sunglow´ and ´Marilee.´

I have two azalea bushes that are fifteen years old and seem to be affected by lace bugs or mites. The leaves have been turning yellowish/silver over the past few weeks. I originally thought the problem was due to too much sun since we have had a very hot Spring, with little rain, this year in Maryland. However, last night when I was watering the plants, I noticed webbing on the bushes and black spots covering the underside of the leaves.

Can you tell me if the problem is mites or lace bugs and how to distinguish between the two pests?

We sprayed the brushes with pesticide and will follow-up in another week or so. How many treatments are necessary?

Finally, I am concerned about the long-term damage to the plants since the problem is severe, i.e widespread throughout the plant. Will the plants recover and return to healthy, green, vibrant plants. How long will it take?

Thank you for your advice.

Lacebug (and mite) populations can increase to the point where they so weaken plants that their survival is threatened.

The use of chemical means of control is a matter of personal conviction. I would certainly avoid wide spectrum insecticides which would kill natural predators and remain in the environment for a fairly long time. Horticultural oils and insecticidal soaps are fairly low impact, but have no residual effect and can also kill predators.

I have used the systemic insecticide imalcoprid (sp.?)- available as Bayer Advanced and other formulations - with good results for several years. This is diluted and poured, not sprayed, on the roots before the onset of lacebug season and seems to give very good control. Since it effects only insects feeding on the leaves, it should not kill anything else.

Timing is important to eliminate the first generation of lacebugs. Your County Extension Service or state agriculture department can tell you when that is for your area. I've found a single application of the Bayer product at half strength works very well as long as the timing is right.

Azalea Lace Bugs, Stephanitis pyrioides: Adults are about 1/8-inch long. The body is pale yellow. The lacy wings (very distinctive) are held flat over the back and are transparent with two dark spots present. The nymphs are black, spiny and smaller than the adults. The eggs over-winter partially embedded in leaf tissue. The eggs hatch in May. The nymphs mature into adults in June and lay eggs during late June and July. The second generation of nymphs appears in August. The over-wintering eggs will be laid when these nymphs become adults. adults and nymphs feed on the undersides of leaves by piercing the leaves with their mouthparts and sucking the plant juices. This causes a mottled, silvery or white discoloration, known as stippling, on top of the leaf where the chlorophyll has been removed. The undersides of leaves are covered with dark brown to black, sticky spots of excrement. Plant rhododendrons in shade to maximize the activities of beneficial insects. The National Arboretum warns: "Excess nutrients may promote larger than normal populations of azalea pests like lace bugs and azalea whiteflies." So don't over fertilize. Most people find that if they mulch with a good conifer mulch, they don't need to fertilize.

Azalea White Mite, Eotetranychus clitus and Southern Red Mite, Oligonychus ilicis: Adult mites are very small, about the size of a period. They are oval shaped, reddish colored, with eight legs. The immatures appear the same, only a little smaller and with six legs. The red eggs over-winter on the undersides of leaves. There are several generations per year. Most activity takes place during the cooler weather of spring and fall. During the heat of summer, the life cycle is in the egg stage. Leaf damage is visible as white stippling damage on both sides of the leaf. In a heavy infestation, the leaves will turn brown, die and may drop off the plant. The undersides of the leaves are often coated with hatched egg shells and shed skins from molted mites. When tapping the foliage onto paper, look for the extremely small, long-legged, light-colored beneficial mites which move quicker than the southern red mites. They may be able to control the pest population. Dormant oil can be used if there is a large number of over-wintering eggs. Certain oil formulations can be used in the summer. Other possible chemicals are avermectin, oxythioquinox and dicofol.

Two Spotted Spider Mite, Tetranychus urticae: This is the most common and destructive mite on deciduous ornamentals. It has an extremely wide host range and will feed on many varieties of trees, shrubs, flowers, weeds, fruits, greenhouse and field crops. Immatures and adults are yellowish to greenish with two dark spots on either side of the body. Eggs are spherical and translucent. Strands of webbing are spun by the mites on the undersides of infested leaves and between branches. Twospotted spider mites over-winter as adult females in the soil or under the bark of host plants. They become active during the spring and may feed and reproduce throughout the summer and into fall provided conditions remain favorable for plant growth. It is considered a 'warm season' mite which thrives under hot, dry summer conditions. Damaging populations seldom during wet, cool weather. The mites are especially destructive to winged euonymous (burning bush) in landscapes.

So if you are getting the webbing, it looks like it is the two spotted spider mite.

Imalcoprid is a systemic insecticide that kilIs a wide range of insectics. It kills insects that eat the leaves or plant fluids, and pollinators that feed on the pollen and nectar. Hence, it has resulted in large losses of honey bees and other pollinators, even when applied to the ground due to the systemic nature.

Here is what an extension bulletin on control says:

Various insects and predatory mites feed on spider mites and provide a high level of natural control. One group of small, dark-colored lady beetles known as the "spider mite destroyers" (Stethorus species) are specialized predators of spider mites. Minute pirate bugs, big-eyed bugs (Geocoris species) and predatory thrips can be important natural enemies.

One reason that spider mites become problems in yards and gardens is the use of insecticides that destroy their natural enemies. For example, carbaryl (Sevin) devastates most spider mite natural enemies and can greatly contribute to spider mite outbreaks. Malathion can aggravate some spider mite problems, despite being advertised frequently as effective for mite control. Soil applications of the systemic insecticide imidacloprid (Merit, Marathon) have also contributed to some spider mite outbreaks.
Spider Mites by W. S. Cranshaw and D. C. Sclar

Control Strategies include:

Option 1: Cultural Control - Syringing
Since rainy weather seems to knock off spider mites, using a forceful jet of water from a hose (syringing) can perform the same task. A regular syringing can keep spider mites under control on most ornamental plants in the landscape. This technique also helps conserve natural predators.

Option 2: Cultural Control - Quarantine and Inspection
The twospotted spider mite is often introduced on infested bedding and house plants. When purchasing new plants, carefully inspect the lower leaf surface for any signs of mite activity. New house plants should be quarantined from other plants until you are sure that no mites are present.

Option 3: Biological Control - Predators
There are numerous insects (lacewings and lady beetles) that prey on spider mites. However, the most commonly sold predators are other types of mites. Predatory mites (usually Phytoseiulus spp., Amblyseius spp. or Metaseiulus spp.) can be purchased and released onto infested plants. Be sure to check listings to determine which species is appropriate. Some species are host specific and each predator works better under different weather conditions. If predators are used, do not apply pesticides that will kill them.

Option 4: Chemical Control - "Soft Pesticides"
Most spider mites can be controlled with insecticidal oils and soaps. The oils, both horticultural oil and dormant oil, can be used. Horticultural oils can be used on perennial and woody ornamentals during the summer at the 1 to 2 percent rate. Higher rates of horticultural oil (3 to 4 percent) or dormant oil are useful for killing mite eggs and dormant adults in the fall and spring. The insecticidal soaps are useful in the warm season. Remember that mites are very tiny and soaps and oils work by contact only. Therefore, thorough coverage of the plant is necessary for good control.

Option 5: Chemical Control - Miticides
Spider mites are usually not killed by regular insecticides, so be sure to check the pesticide label to see if "miticide" is present. Pesticides claiming "for mite suppression" are usually weak miticides and will not perform well.

There are few products available to the homeowner. Dicofol (=Kelthane) is registered for over-the-counter use but is difficult to find. Acephate (=Orthene), dimethoate (=Cygon), chlorpyrifos (=Dursban), diazinon, disulfoton (=Di-syston), and malathion have over-the-counter product labels but are considered weak miticides.

Avermectin (=Avid), bifenthrin (=Talstar), dienochlor (=Pentac), fenbutatin-oxide (=Vendex), fluvalinate (=Mavrik), oxamyl (=Vydate), oxydemeton-methyl (Metasystox-R), oxythioquinox (Morestan), and propargite (=Omite) are restricted use pesticides available only to licensed applicators.
Ohio State Extension Bulletin HYG-2012-92

I'm far from an advocate for saturating the environment with chemicals for garden problems, but rhodyman's first paragraph and the Wikipedia article tend to make blanket condemnations of imidalcoprid's effect on bees as a scientifically proven conclusion when in fact most of the "evidence" is anecdotal and theoretical.

The widespread die-off of honeybee colonies has led to many theories about the causes and a relatively new (in the sense of wide usage) insecticide like imidalcoprid is quite naturally suspect.

As far as I know, however, the most widely accepted current
thinking is that the stress of bee colony trucking from place to place for months at a time and the development of new, more lethal strains of bee mites are the most likely causes.

There's also a big difference in using low-dose, root saturation methods and commercial use of Merit and other imidalcoprid-based insecticides as aerial sprays.

Hi Maingrower,

You are reading too much into that article. It does not intend to solve the hive decline problem with honey bees. It just reports the results of a problem that showed up in France and Germany from imidalcoprid treated seed, not aerial spraying. They actually had dead bees. With hive decline the bees disappear. Also, imidalcoprid may work for lace bug, but it is reported to make mite problems worse according to the Colorado Extension Service.

In the mid to late 1990s, French beekeepers began to experience massive die-offs of bees in and near fields where imidacloprid (Gaucho) was being used. In 1999 after French beekeepers protested in the streets of Paris, the French Minister of Agriculture suspended the use of imidacloprid on sunflower seeds. The French Agriculture Minister also appointed a team of expert scientists to examine the impact of imidacloprid on bees.[5] In 2003, this team of experts called the Comite Scientific et Technique issued a 108-page report, which concluded that imidacloprid poses a significant risk to bees.[6] In 2004, the French Minister of Agriculture suspended the use of imidacloprid as a seed treatment for maize (corn). A monitoring study conducted by Chauzat et al.(2006) in France found that imidacloprid was the most commonly detected insecticide in beehives and was found in 49% of the 81 samples.[7]

In 2008 in southern Germany, beekeepers reportedly lost two-thirds of their bees from clothianidin-treated seeds. As a result of this incident, the German Office of Consumer Protection and Food Safety suspended the use of imidacloprid and clothianidin, but later reinstated some of the uses of these chemicals. Following the German incident, Italy and Slovenia suspended certain uses of imidacloprid, clothianidin, thiamethoxam, and fipronil based on concerns for bees[8]

5 Hasslberger, Seth. Millions of bees dead - Bayer's Gaucho banned.
6 French Scientific and Technical Committee Final Report
7 [Chauzat, M. P., J. P. Faucon, A. C. Martel, J. Lachaize, N. Cougoule and M. Aubert. 2006. Survey of Pesticide Residues in Pollen Loads Collected by Honey Bees in France. J. Econ. Entomol. 99 (2): 253-262]
8 Allison, B. Pesticides: Germany bans chemicals linked to honeybee devastation. Guardian. May 23, 2003

Soil applied neonicotinoids translocate throughout the plant and can be found in the pollen and nectar of flowering plants. Anyone using these chemicals should be made aware of that.