Aphid attack: How to fight back

SALT LAKE CITY — As Utah’s planting and growing season comes in full swing, you may start to see many different pests and insects come out to enjoy the warmth.

If you see curled or distorted leaves, sticky residue on leaf surfaces, clusters of tiny insects on new growth and the undersides of leaves and white cast skins (shed exoskeletons) scattered on foliage, you likely have an aphid infestation.

There are different types of aphids that will go for different plants. Uthans may see green peach aphids, melon aphids and potato aphids.

“Aphids have soft, pear-shaped bodies and red eyes. Adults have tailpipe-like appendages called cornicles on the rear of the body,” according to Utah State University Extension 

The different species are similar in shape and size, mainly differentiated in color. Aphids excrete a sticky substance called honeydew that can attract ants and promotes the growth of sooty mold, which is a black fungal coating on leaves. This is one of the most visible signs of an aphid problem and something viewers may recognize.

Aphids will overwinter as eggs in fruit trees, woody plants, weeds, and even flowers and other crops. When they wake from their winter nap, they reproduce as your plants begin to bud and will lay their eggs in your growing plants.

Aphids can multiply extremely rapidly since they are born pregnant and don’t always need fertilization to reproduce. The young aphids are the most voracious. Since aphids overwinter, you will want to treat them in spring and fall to help prevent infestations.

Aphids mainly go for fruits, but will also attack vegetables like cucumbers, pumpkins and squash. 

Aside from eating your plants, one of the major concerns of aphids is their ability to transmit plant viruses.  Over 100 different viruses can be transmitted by adults as well as nymphs.  Both persistent viruses, which move through the aphid’s feeding secretions, and non-persistent viruses, which are only temporary contaminants of aphid mouthparts, are effectively transmitted by aphids.

A common strain of virus transmitted by aphids is the Potyviruses. They can affect melons, cucumbers, zucchini and more, causing severely reduced leaf sizes and blemishes on the skin of the vegetables. A serious concern with Potyviruses is that they are passed as aphids feed, and can stick around even after aphids are killed, so it is important to do what you can to prevent infestation.

Aphid treatment

Aphids can be easily knocked off your plants by spraying water on them, but you will want to do additional treatment, so they don’t come back.

You can treat your plants with horticultural oils to knock the population back then spray the aphids with Permethrin or Bifenthrin, which will devastate the aphid population. You can use systemic insecticides, but you should be wary because that can affect pollinators. Some commercial growers will introduce predators, like predatory mites, lady bugs, and lacewings, into their gardens.

To help prevent potential aphid infestations, you’ll want to keep your garden clear of plant debris, avoid excess fertilization, and use mulches or garden bed covers.

Listen: More on aphids from the KSL Greenhouse Show👇

 

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