Natural and DIY Pesticides: Common Myths

By Jennifer Gervais

Recipes for DIY pesticides made from household products are easy to find online.
But these options may not be safe or effective.

You’re scrolling through the internet, looking for tips to control some bugs you’ve seen in the kitchen. You want to deal with them just using ingredients you already have rather than buying a product. You’d also rather use a natural remedy because you don’t want to use anything toxic. Sure enough, you find a random blog somewhere (you didn’t pay attention to the site) that assures you that Yes! You can control anything you need to, just by following this special home formula! All you need to do is keep reading.

Before you use the recipe, consider:

  • Natural remedies sound harmless because they are not made up in some chemistry laboratory. However, some of the most toxic substances known to exist are found naturally in plants and animals!
  • Synthetic pesticides are increasingly designed to be less toxic to people and other mammals than insects.
  • Home remedies may include ingredients that have additives that may cause harm. For example, products such as dish soaps or laundry detergents are mixtures of many chemicals.
  • Even familiar pure ingredients such as vinegar can be harmful at concentrations needed for pest control. For example, 20% vinegar can cause permanent eye damage.
  • Mixing or heating substances could expose you to toxic fumes
  • Home remedies don’t come with a label that can help you recognize risks and take steps to reduce them.
  • Home remedies don’t come with instructions for use that have been rigorously reviewed to ensure that the remedy will work while posing minimal risks.
  • They also don’t come with first aid instructions to follow if something goes wrong.

So what can you do?

  • Try integrated pest management first! Identify the critter and learn its life history. That may give you ideas on how to deny the pest food, water, and shelter and take care of the problem without using any chemicals at all.
  • Consider using a commercial product whose label states that the product can be used where you want to use it, and against the pest you want to control. This will keep risks low while giving you the best chance for success. There will be instructions for use and first aid instructions, and a phone number to call if you have questions.
  • Try least-toxic products. You can find information on those products through the U.S. EPA’s Safer Choice program. The Bio-Integral Resource Center publishes a directory of least-toxic products.
  • Ask your local Extension office for assistance!
  • If you have questions about pesticides or related topics, you can reach out to the National Pesticide Information Center. Call the hotline at 800-858-7378, Monday-Friday from 8 am til 12:00 pm, or email them at

Jennifer has a PhD in wildlife ecology from Oregon State University. Her work as a wildlife ecologist has included studying a wide range of species, including birds, small mammals, reptiles, amphibians, and banana slugs. She has published peer-reviewed scientific papers in a number of journals and written numerous conservation and management plans. She has worked as a wildlife ecologist for the Oregon Wildlife Institute and currently works at the National Pesticide Information Center. She volunteers as a Master Gardener trainee and is also involved in efforts to combat climate change.

Upland Prairie photo album

Summer Retrospective Part 3

Photos courtesy of Casey Colley, Kathleen Dennis, Devon Johnson and Mallory Mead.

Oak Creek Center for Urban Horticulture (OCCUH) is a learning laboratory for sustainable horticultural practices in both rural and peri-urban landscapes. The 6.5 acres on the SW corner of the campus house are used for formal and informal OSU research, riparian restoration, a student CSA program, as well as just plain fun. 

This summer, OCCUH invited the OSU Extension Master Gardener (MG) trainees to work on a pilot project renovating and planting beds on the grounds. Kathleen Dennis, the on-site project lead, guided the MG volunteers. Together, the group:

  • Weeded, mulched, and added native wildflowers to an upland prairie area
  • Renovated a high-profile woody hedgerow, and
  • Planted a small hummingbird garden.

The Southern Hedgerow at Oak Creek

Summer Retrospective Part 2

By Sarah Bronstein, Master Gardener

Oak Creek Center for Urban Horticulture (OCCUH) is a learning laboratory for sustainable horticultural practices in both rural and peri-urban landscapes. The 6.5 acres on the SW corner of the campus house are used for formal and informal OSU research, riparian restoration, a student CSA program, as well as just plain fun. 

Last summer, OCCUH invited the OSU Extension Master Gardener (MG) trainees to work on a pilot project renovating and planting beds on the grounds. Kathleen Dennis, the on-site project lead, guided the MG volunteers. Together, the group:

  • Weeded, mulched, and added native wildflowers to an upland prairie area
  • Renovated a high-profile woody hedgerow, and
  • Planted a small hummingbird garden.  

The Southern Hedgerow is a long high profile bed near the parking area for the Bee Lab at OCCUH. The bed is anchored with native woody perennials such as California Lilac (Ceanothus thyrsiflorus) and Oregon Grape (Mahonia aquifolium), as well as show-stopper ornamentals including columnar apples, cardoon (Cynara cardunculus) and coyote bush (Baccharis pilularis). As is often the case in the Willamette Valley’s verdant summers, when the MG work began in August, weeds had encroached in some areas, and plants had grown into one another. The purpose of the Master Gardener Pilot Project in this bed was to weed, thin, and prune the bed to highlight the existing plantings. Empty spaces were planted with ornamentals, many of which were selected to attract pollinating insects and hummingbirds. 

Renovating the Hedgerow proved to be rewarding work. As the weeds were pulled away and spent stalks of Cardoon and Milkweed were removed, Master Gardener Trainee Sarah Bronstein revealed forgotten plants, and made space for new plantings. In some cases, the bed held both pleasant and unpleasant surprises. A rare Heptacodium miconoides was revealed among a thick stand of Douglas aster,  that had shielded it from summer rays. 

Bronstein had the benefit of utilizing OCCUH’s plant stock, including red and blue ornamental sages (Salvia elegans), variegated butterfly bushes (Buddleia davidii), and an olive tree. A wildflower mix and wild strawberries were tucked in between other plants to help cover the ground and prevent future weed invasions.

In the coming year human, insect, and avian visitors to Oak Creek will be welcomed by the silvery hues of Cardoon, Coyote Bush, and Milkweed in the Southern Hedgerow, accented by the bright colors of purple Buddleia flowers and ornamental sage.

OCCUH’s mission is to utilize open expanses in a more coherent urban-based fashion. Urban Meadows, Green Roofs, pollinator space, and urban wildlife habitats are all on the drawing board. The Center is always looking for volunteers to help with projects.

Planning an “Eat the Rainbow Garden”

By Karen A. Mills, Master Gardener

Nutritional resources reviewed by Tina Dodge, OSU Extension

Photo: nadine-primeau-unsplash

It’s time to plan your garden and even start a few early varieties. Perhaps, like most gardeners, you are taking stock of your garden successes and challenges and considering different paths for this year. Have you ever considered planting an “Eat the Rainbow Garden”? An Eat the Rainbow Garden is a garden that produces delicious fruit and vegetables in every color. Clearly, this type of garden would be vibrant, but did you know that creating this type of garden can also support your health?

Growing your own fruit and vegetables increases your access to healthy food, which in times of inflation is more important than ever. Gardening also increases the likelihood that you and your family will eat more fruit and vegetables than families who do not garden. And, when kids are involved in the planning, planting, growing, and harvesting of produce, they are much more likely to have a diet high in fruit and vegetables.

Growing a Rainbow Garden can certainly capture the imagination of kids, but they are just as important for adults. Rainbow Gardens support health exactly because they include all colors of the rainbow. Each color that we see in fruit and vegetables is created by phytochemicals (sometimes called phytonutrients), which are bioactive compounds found in plants that provide color, taste, and smell. Phytonutrients help out plants by protecting them from different diseases and too much sun. Phytonutrients may help people out by supporting our immune system and offering protection against different types of chronic diseases. Every phytonutrient color represents a different compound, each of which comes with different possible health benefits. See the table below for some delicious and colorful options!

Now that we know what an Eat the Rainbow Garden is, how do we build it? Here are some tips to get you started:

  • Location, location, location! It is important to understand your garden site. Get to know your site’s climate, soil, weather exposure, and sun. If you are just starting your garden, this is the opportunity to consider these topics when you select a garden site. Good garden site preparation sets the foundation for a successful gardening experience. For site preparation and selection tips check out:
  • Choose your colors. The colors of the rainbow are red, orange, yellow, green, blue, indigo (a darker purplish blue), and violet (purple). Blue, indigo, and violet phytochemicals are often grouped together, but you can separate them in your garden for a beautiful effect. You can also add to the rainbow by including white, like a cloud! It can be a lot of fun to pick produce based on color. You can choose many different varieties of plants to cover the colors, or you can pick just a few types of vegetables that come in many colors, such as carrots, peppers, tomatoes, or even potatoes! Some examples can be found here:
  • Plan plant placement. Now that you know your garden site and what fruits and vegetables you would like to try, it is time to consider plant placement. It might be tempting to group plants by color in a rainbow garden, however, each plant has its own garden needs. For example, cabbage prefers cool, moist conditions, and cucumbers prefer warm, dry conditions. Even though they are both green, it could be difficult to care for these plants if they are planted next to each other. Check out a resource like  for what plants do well in what kind of conditions.
  • Consider containers. If you garden on a patio or deck, or if your garden site is limited, consider container gardening. Containers can also be a great add on to an established garden, giving you the opportunity to add a plant that might not quite fit into your garden plan or rotation. Look for varieties that are specifically adapted for containers. Blueberries, cucumbers, tomatoes, leafy greens, peppers, potatoes, strawberries and many other plants have container options. OSU’s Growing Your Own – A Practical Guide to Gardening in Oregon (found here: ) contains many basic tips to help you get your garden started including a section on varietals that grow well in containers in Oregon.  Check out this link ( ) for more suggestions on specific vegetable varieties that do well in containers.
  • Want more information? If you are interested in exploring a particular phytonutrient and the foods and health benefits associated with that particular phytonutrient, this is a good resource: . And if you are science savvy, check out this good, very technical resource on phytochemicals:

Eat the Rainbow Gardens are not only beautiful to see but they can promote healthy eating. With so many colorful fruits and vegetables to choose from, experiment and have fun!

ColorMain PhytonutrientsGarden Options
RedAnthocyanins (including lycopene), antioxidantsApples, beets, cherries, radishes, red onions, red pears, red peppers (bell and hot), red plums, rhubarb, strawberries, tomatoes, watermelon
OrangeCarotenoids (including beta-carotene)Apricots, carrots, nectarines, orange bell peppers, peaches, sweet potatoes,
YellowBio-flavonoids, luteinApples, Asian pears, corn, potatoes (Yukon golds), summer squash, winter squash (acorn, butternut, etc.), yellow beets, yellow bell pepper
GreenCatechins, chlorophyll, flavonoidsAsparagus, Brussels sprouts, bok choy, broccoli, broccolini, cabbage, cucumbers, green peas, leafy greens (chard, collards, dandelion, kale, lettuce, mustard, spinach, etc.), okra, peppers (bell, jalapeno, poblano, serrano), tomatillos, zucchini
Blue, Indigo & Violet*Anthocyanidins, flavonoids, phenolic acids, resveratrolBlackberries, blueberries, eggplant (Italian or Japanese), figs, huckleberries, plums, purple bell peppers, purple cabbage, purple carrots, purple cauliflower, purple grapes, purple kale, purple potatoes
WhiteAllicin, flavonoids, indolsCauliflower, daikon radish, garlic, mushrooms, onions, parsnips, potatoes, turnips,

*Blue, indigo and violet phytonutrients are often grouped together.

Algert, S. et al. (4/1/2016) Community and home gardens increase vegetable intake and food security of residents in San Jose, California. California Agriculture. 70(2):77-82.  Accessed on October 17, 2022.

McManus, KD. (4/25/2019). Phytonutrients: Paint your plate with the colors of the rainbow.   Accessed on October 17, 2022.

Minich, DM. (2019) A review of the science of colorful, plant-based food and practical strategies for “Eating the Rainbow”. J Nutr Metab. 2019:2125070. doi: 10.1155/2019/2125070  Accessed on October 17, 2022.

Houseplants for everyone

Resource list curated by Carrie Falotico (Master Gardener Trainee), Leo Sherry (Master Gardener Trainee), and Elizabeth Records (Education Program Assistant, OSU Extension Service)

A variety of small houseplants in a sunny window. Credit: Getty Images

Why this list?

The internet is full of tips for houseplant care. But not all of them are based on science or proven to be safe and effective. So Master Gardener Trainees Leo and Carrie researched these suggestions just for you! Whether you are new to houseplants or are familiar with growing them, we hope this list of research-based resources will support your success.

Which houseplants are right for me?

If you have pets or children, consider non-toxic houseplant options. Credit: Getty Images

How much light your dwelling gets, how much time you have, and the people and pets in your home, are things to consider when picking houseplants.

How do I start houseplants from cuttings?

Many types of houseplants can be rooted from cuttings. Credit: Getty Images

You got a cutting of a houseplant! How do you grow it into a full-grown plant?

How do I care for houseplants?

Some plants need to be misted with water. Credit: Getty Images

Different plants have different needs. Keep your plants happy with these resources.

How do I fix houseplant pests or diseases?

A sticky card is used to trap insects on a plant. Credit: Getty Images

Your houseplant looks sick or has bugs. These resources can help.

What kind of houseplant is this?

A small collection of varied houseplants. Credit: Getty Images

Knowing the types of plants you have is key to successfully growing them. Find your plants in this list, or contact your local Extension office.



Specific plants:


African Violets

Air Plants

Small Aloes – Interesting, Colorful, and Easy Succulents

Amaryllis, Hippeastrum

Asparagus fern, Asparagus densiflorus

Boston Fern, Nephrolepis exaltata ‘Bostoniensis’ 


Burro’s Tail, Sedum morganianum

Indoor Cacti

Chinese Evergreen

Croton, Codiaeum variegatum

Crown of Thorns, Euphorbia milii 




Elephant Bush, Portulacaria afra

Ficus benjamina

Fiddle Leaf Fig Houseplant – Proper Care 

Haworthias – Super Succulents for Small Spaces 

Holiday Cactus

Jade Plant, Crassula ovata 


Living Stones: Lithops


Indoor Palms

PoinsettiasPolka Dot Plant, Hypoestes phyllostachya 

Ponytail Palm, Beaucarnea recurvata

Pothos, Epipremmum aureum 

Rubber Plant


Shamrocks, Oxalis spp. 

Snake Plant: A Forgiving, Low-maintenance Houseplant

Spider plant, Chlorophytum comosum

Split-leaf philodendron, Monstera deliciosa 

Staghorn Fern, Platycerium bifurcatum

String of Hearts, Ceropegia woodii

String of Pearls, Senecio rowleyanus

Stromanthe sanguinea “Tricolor”

Tradescantia zebrina

Zamioculcas zamiifolia (ZZ plant)

Trap Crops: what are they and how can they help control pests?

By Carrie Falotico, Master Gardener Trainee

Crucifer flea beetles (Phyllotreta cruciferae) and Brassica juncea, a trap crop that attracts these pests.

Plant pests can certainly be one of the most frustrating parts of growing your own food garden. Trap crops are part of an Integrated Pest Management plan. Here’s how they work. 

A TRAP CROP can be defined as a sacrificial plant that draws away damaging insects from the desirable crop.

Essentially, a trap crop works as an alternative host that draws away invading insects, giving the main vegetable crop an added layer of protection. In some cases, insects have a preference for these alternative hosts, and when given the choice, will go to the trap crop first.  After trap crops are infested with target insects, they can be controlled with timely insecticidal applications or mechanical removal. While trap cropping can be extremely beneficial, it is often not a complete solution. Trap crops will not control all insects and the use of integrated pest management (IPM) is necessary. IPM practices include rotating crops, attracting beneficial insects, and prudently using organic and synthetic chemicals.

This article gives a great explanation of trap cropping for small commercial growers. Many of these practices are also very useful in the home garden and can be done on a smaller scale.

Another great resource that details trap crops as well as intercropping and companion planting, that, when combined with trap crops, can make an even bigger impact when controlling pests.

Identification is key

You will definitely want to make sure you have correctly identified the pests causing damage to your plants. Different pests may prefer different trap crops and may require different integrative pest management (IPM) techniques. This resource is a helpful guide to identifying common pests as well as insects that are beneficial and helpful to gardeners.

Example: Flea beetles 

Flea beetles (including Epitrix spp. and Phyllotreta cruciferae) are a well-known garden pest on crops like kale and broccoli. For flea beetle control, Chinese southern giant mustard (Brassica juncea var. crispifolia) is an example of a trap crop that has been used effectively in the United States to protect crucifer crops from flea beetle damage. In studies conducted at Washington State University (WSU), a diverse trap crop containing Pacific Gold mustard (B. juncea), Dwarf Essex rape (B. napus), and pac choi (B. campestris L. var. chinensis) successfully protected broccoli from the flea beetle. Diverse trap crop plantings combine plants that have different phenologies (life cycles which can be influenced by the environment, weather conditions, and nutrition), chemical profiles, and physical structures that make them more attractive to flea beetles. 

It is important to note, however, that trap crops may not provide complete protection, especially during heavy pest infestations. You also have to manage the pests on the trap crop by removing them by hand and killing them, or using insecticide. Trap crops will be even more effective if several integrated pest management strategies are used together, like 

  • Control weeds in and around planting sites to limit food sources for flea beetles.
  • Remove old crop debris so that beetles will not be able to get protection in the winter.
  • Plant crops as late as possible. Plants grow faster in warmer temperatures and are more stable to resist damage from flea beetles.
  • Use row covers or other screening to keep beetles out when the seedlings are growing.
  • Remove row covers before the flowers come up so pollinating insects can reach the plants.

These articles give excellent detail on managing flea beetles:

Explore more

If you are interested in reading more about Integrated Pest Management and how it can help your garden thrive, this is a great resource

I hope you find this information helpful and that these methods help you have a more enjoyable gardening experience!

Linn Master Gardeners win award for pollinator newsletter

 Congratulations to Linn County Master Gardener Association for winning the Marje Luce Search for Excellence from Oregon Master Gardener Association, for their publication Bee Notes.

Bee Notes raises awareness about stewarding native pollinators, including timely tips for care of blue orchard mason bees. Bee Notes is a key component of the outstanding pollinator education initiatives of Linn Master Gardeners, including the BEEvent Pollinator Conference which won this same award in 2019.

Search for Excellence is the recognition program of Master Gardener volunteer work, both throughout the United States and Canada (at the International level), and across the State of Oregon within the OMGA.

In Memory of Marti Olsen

We were sad to learn that onetime Master Gardener volunteer Marti Olsen passed away in July 2022. Fellow volunteers recall that Marti truly loved gardening especially roses. Marti, we miss you.

In 2005 no one stepped forward to take over Through the Garden Gate tour and the board had decided not to have it that year.  Marti didn’t want to see that happen so she started trying to recruit folks.  I was a new trainee that year.   Marti convinced me my garden was worthy to be on tour.  It was March with only a few months to go till the tour.  Not much time to get my garden ready for the tour but I agreed.  The problem was we were still 2 gardens short. Marti asked if I had any ideas. We ended up recruiting two of my wonderful neighbors with beautiful gardens. Had it not been for Marti stepping up the garden could have just been a memory. ”

– Nancy Messman, Linn County Master Gardener Association. 

Read an obituary for Marti Olsen HERE.

7 Steps to Maximize Your Harvest’s Nutrients

Written by: Karen Mills, Master Gardener Trainee

Credit: cottonbro

Eat more fruit and vegetables! We have all heard this command from many sources. And for good reason! Produce is the main source of many vitamins and minerals, fiber, and other nutrients in our diet. Did you know that if your garden includes fruit and vegetables, you may eat more produce than people who do not garden? This warms the hearts of your parents, dietitians, and doctors.

Any produce you eat is a good thing and includes all of those nutrients your doctor is hoping you will eat. But it does beg the question, is one tomato the same as another? Does a tomato have the same amount of nutrients in it regardless of where that tomato comes from, how it was grown, and how it is processed? Not necessarily. The condition of your soil, how you manage your garden, and how you harvest, store, and process your bounty can all impact the nutrient content of your produce. Whether you grow cucumbers in a container on your patio or have a large garden in your yard, how can you make sure that the produce you grow has the most nutrition possible? Follow these 7 steps to get the biggest nutritional bang for your buck

Test Your Soil pH

  • The nutrient content of produce begins with healthy soil. If your garden soil pH is off, nutrients that might be in the soil may not be available to your plants. For example, if your soil is too acidic, your plants may not get enough calcium leading to blossom end rot in your zucchini and tomatoes. Adjust your soil pH in accordance with test results.
  • More information on soil pH

Test Your Soil Nutrients

  •  If your soil lacks nutrients, your produce will also lack nutrients. A soil test can tell you the amount of phosphorous, potassium, calcium, magnesium, sulfur, and micronutrients you have to work with. Fertilize and amend your soil in accordance with the soil test, plant needs, and package instructions. Proper use of fertilizer and soil amendments can optimize produce flavor, texture, color, size, nutrient composition, and shelf life. Be careful – too much fertilizer can be just as bad as too little!
  • More information on fertilizing your garden.

Manage Your Garden Watering

Time Your Harvest

  • Know when your vegetables are at their peak and harvest as close to that time as you can. Every fruit and vegetable has its unique indicators of when to harvest. While many vegetables are at their highest deliciousness when allowed to fully ripen on the plant, allowing some vegetables to remain unharvested past the peak ripeness can result in inedible produce. For example, okra becomes woody and inedible when left to grow after peak maturity is achieved. Some produce can continue to ripen after harvest. While harvesting prior to maturity may prevent the neighborhood deer and squirrels from snacking on your tomatoes, early harvest means tomatoes lower in vitamin C than tomatoes left to ripen on the plant.
  • More information on harvesting, handling, and storing popular home garden crops.

Eat or Process as Quickly as You Can

  • Reduce the time between harvest and eating or processing as much as you can. As soon as you harvest fruit and vegetables, they start to lose nutrients. After all, you have removed the produce from the plant that provides nutrients and water. 

Store Your Harvest Appropriately

  •  If you do need to store your harvest, make sure that you are doing so correctly. Each type of produce prefers a specific type of storage environment. Storing your harvest correctly not only keeps it fresh longer but also helps retain nutrients. Some produce, such as snap beans, prefers cold, moist storage. Some produce, such as winter squash, prefers warm, dry storage.
  • More information on the particulars of storage

Pick a Preservation Method That Retains Nutrients

Nothing beats the taste of freshly picked, home-grown produce. Using these tips will help you get the most nutrition you can from all of your hard work, patience, and perseverance. Happy gardening!


Pests In July

Written By: Chad Kuwana, Master Gardener Volunteer Trainee

Black vine weevil
Credit: University of California Agriculture & Natural Resources

Check back in with your azaleas and rhododendrons this summer!

At this point of the year, summer is in full swing and daily high temperatures are consistently in the upper eighties and nineties. The beautiful spring weather that brought about stunning blooms in your garden is just a memory as you try to beat the heat with some freshly picked berries.

While some spring blooms may be holding on, most azalea and rhododendron bushes have lost their flowers and your attention has likely shifted to other parts of your garden like your fruits and vegetables. However, as you water your plants, you might notice notched edges on the leaves or fuzzy white spots on the branches of your azaleas or rhododendrons. These are signs that black vine weevils or scale might be present on your plants.

Black Vine Weevils – Otiorhynchus sulcatus


Black vine weevils are a type of beetle (Curculionidae) about ½ inch (12.7 mm) long. They cannot fly and are mostly black with small patches of white. The larvae are also about ½ inch (1.27 cm) long but are white with a brown head. Adult black vine weevils eat foliage and are most active at night. You will notice notches in leaves from where they were feeding. Larvae, however, feed on the roots of your azalea or rhododendron, so they can cause more severe damage to your plant as it can lead to diseases like Phytophthora root rot.

Damage from the black vine weevil.
Credit: University of California Agriculture & Natural Resources

Life Cycle

The reason you might be noticing evidence of their presence in July and early August is because of their life cycle. Black vine weevils usually emerge between May and June after overwintering in their larvae stage. Upon emerging they need anywhere between 21 and 28 days of feeding before they are ready to lay eggs and begin a new generation. Thus, peak adult populations are seen in the summer. Once they are ready to lay their eggs, black vine weevils can lay as many as 500 eggs over a two to three-week period.


Assuming you don’t have cultivars that are less susceptible to weevils in your garden, there are a few things you can do. 

If you’ve caught it early and the weevil population isn’t overwhelming, you can get rid of the weevils by hand. Once it’s dark (remember they are active at night), you can shake and beat the leaves over a sheet that will collect the fallen weevils and then dispose of them.

Another option is to use corrugated cardboard as a wrap around the trunk (also overnight). This wrap will serve as a trap so that when they seek shelter during the day, you can collect and dispose of them. Instead of a cardboard wrap, you can use a sticky material that will trap the weevils as they crawl up and down the trunk.

Lastly, you can also use parasitic nematodes to help control the infestation at the larval stage.

Azalea (rhododendron) Bark Scale – Eriococcus azaleae

Credit: Michigan State University Extension


Azalea bark scale are small insects about .13 inches (3.3 mm) long. They are red in color but are most recognizable by the fuzzy white sacs on twigs and branches. These egg sacs or ovisacs are important to remove during the summer so they do not hatch. When they hatch in September, the young scale will start to feed on the azalea or rhododendron by penetrating the bark and sucking out sap and will excrete a substance called honeydew. This honeydew will invite sooty mold and fungi to grow and cause your plant to look darkened, yellow, and/or sickly.

Credit: Michigan State University Extension

Life Cycle

The azalea bark scale lay their eggs in early April to hatch in May. During the summer, the young scale will feed and mature to produce the fuzzy white sacs in June and July. This is when you might notice the sticky substance on branches called honeydew and sooty mold covering the leaves. You might also start to see more fuzzy white sacs on the twigs and branches.


Starting with the fuzzy white sacs, you can brush them off with your fingernail or toothbrush. If an area is heavily infested, pruning is the best method for removal. Keep in mind also that fertilizing with too much nitrogen will support the population growth of scale.

Wrapping Up

Hopefully, this post can help you get familiar with these two pests that might be hurting your azaleas and/or rhododendrons. Please reference the resources below for more detailed and extensive information on monitoring and controlling these pests in your garden. It’s easy to forget all the details that go into keeping up your garden so make sure to check in with the OSU Extension Monthly Garden Calendar to help you stay on top of key garden chores throughout the year.