Pests in the Garden

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Pests in the Garden

Understanding Common Garden Pests. Part 1. Aphids, Snails/Slugs, and Scale.

A healthy garden is a very comfortable place for an insect to call home. There are many different pests that may visit our plants, and most of them are easily dealt with. One of the most important parts of managing a pest is identifying the pest itself. Different bugs call for different treatments. Any sprays I recommend are organic and safe to use, even on your veggie gardens. A good rule with sprays is to only use when you see the pests. Best time to use sprays is in the evening when the sun is going down. Spray weekly until the problem is solved.

Pest Name: Aphid

Identify: Aphids are small insects, about half the size of a grain of rice. They could be white, green, black or yellow. Usually found in large colonies on a plant. When you see a trail of ants on your plants, you can usually trace it back to a group of aphids.

Where are they found: Aphids are attracted to the softer growth on a plant, this means leaves and especially new growth shoots.

Treatment: Luckily aphids are easily treated. You can use beneficial insects such as ladybugs and lacewings to keep populations down. You can also spray an insecticidal soap or Neem Oil.

What do they do:  Aphids suck nutrients out of our plants and excrete a sugar that will collect on the leaves. When this sugar sits on the leaves it develops a black sooty mold. If unchecked the sooty mold will cover up your leaves and slow down their vigor.

Pest name: Snails/Slugs

Identify: They range in size from the size of a fingernail to the size of a thumb. They leave slimy trails on and near leaves.

Where are they found: Snails and slugs are generally active at night, early in the morning, or on rainy days. During the day they will hide in shady or consistently moist areas in your gardens. Under rocks, pots and pavers, or under the lip of your pots.

Treatment: Snails can be controlled by a few different methods. You can release decollate snails, and they will eat the snails that eat your plants. You can use Sluggo, which is safe to use around your veggie gardens and even around pets. With Sluggo, apply it either around your plants so they cannot pass, or around where you think they are hiding. You can also use copper tape as a border that they will not pass. Also tossing them in the street for the birds is an effective way to keep the numbers down. It’s worth mentioning that people who change their gardens to CA friendly or Native have way less snail problems. Snails like consistent moisture and really don’t like to travel over dry terrain. Ask your friend with a truly drought tolerant garden how many snails they have to deal with.

What do they do: Snails and slugs can do a lot of damage to a plant’s leaves. They have rasping mouth parts, so the damage they cause on thicker leaves can be similar to the effects of sand paper, thinner leaves it would just be a hole in the leaf.

snail with trail

Pest Name: Scale

Identify: Scale is a small round insect that looks like a scab on a leaf. You always know it is scale because it can be picked off of a leaf with your fingernail, like a scab.

Where they are found: Scale is most comfortable in a shadier spot on your plant. This can mean the underside of leaves, or the stems behind foliage.

Treatment: The best way to treat scale is to spray an oil spray on them, such as Take Down or Neem Oil. Make sure to spray the undersides of the leaves and the stems.

What do they do: Like aphids, scale are also sucking insects. They pull nutrients out of the leaves and excrete a sugar that drops down to the leaf below. The sugar develops black sooty mold.

When treating for a pest in your garden, it is always good to consider using beneficial insects first instead of spraying. When you do spray, make sure to spray in the evening, when the sun starts to go down and the temperatures are cooling off. A lot of the beneficial insects such as bees will have gone home by then. Spray your plant weekly with the recommended organic spray, until the problem goes away. Sluggo should be applied every two weeks. All of the sprays that we carry at Roger’s Gardens are organic and safe to use even on your vegetables. If ever you are unsure what type of pest is on your plant or what to spray it with, feel free to call us at Roger’s Gardens or even bring in a sample for us to examine.

By |2016-04-28T15:43:04+00:00April 28th, 2016|Gardening, Gardening 101 Series|2 Comments

About the Author:

Ron Vanderhoff is a lifelong Southern California gardener and the General Manager and Vice President of Roger’s Gardens. He is a local director of the California Native Plant Society and serves on a number of state and local advisory committees involving horticultural education and natural resource protection. He was a principal contributor to The Butterflies of Orange County and The Wildflowers of Orange County and the Santa Ana Mountains, as well as a special contributor to The Sunset Western Garden Book.


  1. Kathleen Reardon June 1, 2016 at 1:27 pm - Reply

    What tree will you advice to plant where my birch tree is dying and will have to be removed,
    it is on the fronr yard by the street . I am in Huntington Beach, I am considering eiher a CASIA , CRAPPLE MYRTLE or JACARANDA Thank you Kathleen Reardon.

    • Roger's Gardens June 3, 2016 at 9:35 am - Reply

      Hi Kathleen,

      Glad you enjoyed the article. Sorry to hear about your failing birch, but this has become a rather regular situation with this species. The warmer, drying summers that we have been experiencing lately have stressed many birches and we are seeing similar scenarios around the county.

      Of the three species you mentioned, there are of course many, many variables. Not seeing the site or knowing anything about the surrounding plants, the neighborhood, your tastes or interest in gardening I am a little tentative in giving any definite answer. Nonetheless, I am hesitant about Cassia’s as street trees. Their low branching and weak limb structure would concern me. Crape Myrtles could work as long as a mildew-resistant variety is selected. The hotter and drier the air the better for this species; sometimes right on the coast they can be a bit challenging unless they get a lot of reflected heat and great air circulation. Jacarandas can be beautiful, large trees. Be sure to give them enough room and do understand that when they are in full bloom there will be a great deal of flower drop onto sidewalks and any parked cars.

      There are many, many other trees to consider as well. A drive around your neighborhood and other nearby neighborhoods is probably the best ways to “shop” for a tree. Look at what you like and don’t like, then do a bit of quick research to learn about any seasonal changes in the tree, its ultimate size, etc. If you don’t know what the tree is that you are looking at, just snag a couple of leaves or some photos (close ups of the foliage are important). Seeing mature trees in real-life situations in the same soil and climate as you are in is far better than looking at photos on a website or looking at young plants at a garden center. Another good resources is this site: Even though the information is from San Diego it offers some good advice and the climate is almost identical.

      Of course, once you make your final decision we would be happy to order your new tree for you. We will be sure to get the highest quality available.


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