Problem Identifier / How to Identify and Get Rid of Aphids

What are Aphids?

Aphids are insects with soft bodies, and sucking mouthparts used to pierce plants. This enables the pests to feed on the sap. In most cases, aphid colonies are found on the underside of the leaves. There are about 5,000 different species across the globe in the Aphididae family.

Although moderate to low populations are not generally harmful to gardens and plants, learning how to get rid of aphids in larger numbers is important to eliminate potential damage. Aphids are found in crops, gardens and trees. They are one of the most destructive insects due to their ability to reproduce so quickly. They are often located in more temperate climates and each species is attracted by a different type of plant.

How to Identify Aphids

Aphids are tiny, with a length of just one-eighth inch. These insects have soft, pear-shaped bodies in a wide range of colors including yellow, red, green, black, red and brown. The coloration is dependent on the food source and species. Most adult aphids do not have wings but are capable of growing them when found in large enough populations.

This is because wings enable the aphids to travel farther when food becomes scarce. When the insects reach new plants, they reproduce, then begin a new colony. Feeding usually occurs in large numbers, although small or single numbers occasionally feed. In order to get rid of aphids, the insects must be correctly identified first. Look for two antennas resembling whips at the tip of the head, and a pair of cornicles.

Aphid Life Cycle

The most unique feature of aphids is the ability to reproduce either sexually or asexually. Both methods are used, with the biggest factor being the environment. Asexual reproduction enables the female to lay eggs or produce live clones without the presence of a male, which leads to numerous generations per year.

Aphid Nymphs
Aphid nymphs. PHOTO CREDIT Whitney Cranshaw, Colorado State University, Bugwood.org

The fast reproduction cycle makes it exceedingly difficult to get rid of aphids, which is why we always recommend using Trifecta Crop Control as a preventative measure. Once an infestation is present, aphids can be very difficult to eradicate.

The mild climate in California enables adult females to produce live offspring throughout the year without mating. As many as 12 live offspring are often birthed each day! The young insects are referred to as nymphs. The nymphs shed their skins approximately four times during the molting process before reaching adulthood.

Aphids do not have a pupal stage. Certain species produce eggs after mating during the fall and winter months, producing a generation capable of surviving harsh winters with extraordinarily little foliage. This generation is so hardy, it is just another factor that can contribute to difficulties overcoming an infestation. Some eggs are laid on perennial plants to improve the chance of surviving throughout the winter.

During warmer weather, numerous aphid species only need seven or eight days for the development from nymphs to adults. Populations increase very quickly because every adult aphid can create 80 offspring in just one week. Adults and nymphs attack roots, flowers, stems, fruit, buds and leaves for the plant juices. Aphids are attracted to new growth, with some species feeding on numerous types of plants, and others on just one or two.

What do Aphid Eggs Look Like?

Aphid Eggs
Newly laid aphid eggs are a yellowish green color but turn black as they harden. The white object is the hatched egg of a syrphid fly, an aphid predator. PHOTO CREDIT Whitney Cranshaw, Colorado State University, Bugwood.org

Aphid eggs are either oval or chisel-shaped. The eggs are attached by threads or supports. Recently-laid aphid eggs have a light yellow-greenish coloration, with the shade becoming darker as the eggs mature. Certain aphid species cover their eggs with wax to make them distasteful to predators. These eggs will look grey due to the deposit of wax, despite their yellow coloration. There is no surface wax on mature aphid eggs.

Aphid eggs are frequently laid on the leaves of plants or trees. Some species lay eggs on young branches with nearby buds, or on the actual buds. Aphid eggs are often hidden in crevices close to a food supply. Some species gather in extremely large numbers on thick branches, then lay an enormous number of aphid eggs. When the season is ending, damaged or old aphids lay eggs in unusual areas such as old sticks, greatly decreasing the chance of survival.

How Do You Kill Aphid Eggs?

Applying the essential oils and soap found in Trifecta Crop Control just as eggs are beginning to hatch in early spring will ensure you are destroying existing generations of this pest and preventing them from reproducing.

Aphid eggs can be destroyed with a powerful stream of water. This method should be used during the early season to be the most effective. Although this is not a good option for cannabis, more delicate or younger plants, it is effective for plants able to withstand higher water pressure.

Aphid eggs can also be removed by hand by knocking them off flower buds, leaves and stems. Allowing the aphid eggs to fall into a bucket with soap and water is a good way to get rid of eggs after they have been identified. The affected areas can also be pruned but make certain the cuttings fall into the bucket.

What Does Aphid Damage Look Like?

Aphid Damage on Cannabis Plant
Closeup of aphid damage on a cannabis plant. PHOTO CREDIT  Mel Frank

The best way to get rid of aphids is by learning how to identify the damage for earlier detection including:

  • Yellowing, stunted, misshapen or curled leaves
  • Sticky substance on the leaves
  • Sooty mold fungal growth
  • Deformed fruit and flowers
  • Galls on the leaves and roots
  • Ants in infected areas

Look for yellowing, stunted, misshapen or curled leaves. Always look beneath the leaves because this is a common hiding place for aphids. If there is a sticky substance on the stems or leaves, you know you need to get rid of aphids. Ants may also be present because they have been feeding on the sap. The waste of aphids is called honeydew. This sugary substance can be seen when there is an infestation.

Honeydew attracts many insects including ants. Honeydew frequently results in the growth of sooty mold fungus. When this happens, the leaves and branches look black. Feeding aphids cause deformations and distortions in flowers and fruit, or the formation of galls on leaves and roots. Aphids can transmit viruses among the plants.

How to Get Rid of and Prevent Aphids Naturally

Cannabis and Hemp Growers

For infestations

The essential oils in Trifecta Crop Control are highly effective for getting rid of and killing aphids naturally. Apply following our infestation application of 2oz per gallon every 24 hours until the infestation is under control. Then switch to a preventative. This should be sufficient to keep aphids from returning to the plant.

For prevention

Applying Trifecta Crop Control as a preventative is the best way to prevent aphids naturally. When you are proactive, you save yourself the possibility of the stress an infestation can bring. Apply as follows or click here to view and/or download our complete Application Guidelines.

  • .5oz per gallon applied once per week during veg
  • 1oz per gallon applied once per week during flower up to 2 weeks before harvest for cannabis plants. Crop Control can be applied up to the day of harvest for fruits and vegetables. Please wash your produce before consuming to remove any residual product.

Home Flower and Vegetable Gardens

Aphid Infestation Artichoke Plant
Aphid infestation on an artichoke plant.

For infestations

If you are treating a sturdy vegetable or fruit plant such as broccoli, melons, etc. – you can use a strong stream of water to spray the aphids off the plant prior to applying Trifecta Crop Control. Focus on the entire plant, including the underside of the leaves.

Apply Trifecta Crop Control at a dilution of 2oz per gallon every 72 hours until the infestation is under control. Then switch to a preventative of 1oz per gallon, once per week. Click here to view and/or download our complete Application Guidelines.

For prevention

Aphids can reproduce VERY quickly. Once you have an infestation, they can be difficult to eradicate completely. Always, ALWAYS use preventative measures to ensure your plants stay safe and healthy! Apply Trifecta Crop Control as a preventative to keep your plants aphid free. Our preventative application is as follows:

  • .5oz per gallon applied once per week during veg
  • 1oz per gallon applied once per week during flower up to 2 weeks before harvest

Benefits of Insects in Gardens for Eliminating Aphids

Certain insects are beneficial including lacewings, ladybugs and lady beetles. These insects frequently consume a lot of aphids. Consider them a welcome addition to your garden. Not only do ladybugs eat aphids, but they also eat other pests. You can purchase ladybugs, then release them where you are growing your plants. The issue is although they kill aphids naturally, they usually fly away within just a few days. Another issue is aphids reproduce so quickly, releasing ladybugs might not be enough to ensure any aphids remaining are below the acceptable levels.

If you already have the beginnings of an infestation, ladybugs may not be enough. Assassin bugs are a good option to control aphids naturally because the heat does not affect them as much as ladybugs. Assassin bugs are considered effective predators for aphids. Just like all the other parasites and predators, assassin bugs need to be released as soon as you see aphids. If you need a fast-acting predator, minute pirate bugs are a good option. This type of bug continues controlling insects after they have fed, ensuring they are reliable for curbing the growth of aphids.

You can also limit the population growth of aphids by releasing green lacewings. These bugs are good for moderate control on a farm or in a garden. At times, you may see an ant farm developing around aphids for the collection of honeydew. Unfortunately, the number of aphids is consistent when ants are around.

 

By controlling the ants, you can often control aphids as well. Ants protect the aphids from predators, such as lacewings and ladybugs. By doing so, they are protecting their honeydew food source. They have also recently been found to protect the aphids from a fungal outbreak that causes death, by removing the bodies of the infected aphids.

Whenever you see an infestation of ants on a tree or plant, it is likely you have an infestation of aphids.

Natural Aphid Management in Greenhouses Using Biocontrol

You can manage aphids with lacewings available as either larvae or eggs. The larvae are voracious predators feeding on aphids, mealybugs, spider mites, scales and thrips. Eggs are less expensive but work slower than larvae. Lacewings are available as adults, immature or eggs.

The release rate for adults is one for five to 30 aphids, a curative release of ten larvae for each square yard or 1,000 eggs for every 200 square feet. You should use lacewings every 1 to 3 weeks, as necessary.

  • Due to the cannibalistic nature, you need to spread the larvae throughout the area
  • Aphids hide during the day, but new plant growth is a good sign
  • Ants defend aphids and eat lacewing eggs so they must be controlled for lacewings to be effective
Aphid Colony on Cannabis Plant
Aphid colony on a cannabis plant. PHOTO CREDIT Whitney Cranshaw, Colorado State University, Bugwood.org

Larger aphids including the potato aphid can be controlled with a parasitoid wasp called Aphelinus abdominalis. The adults parasitize and feed on aphids. They work more slowly than other parasitoid wasps but control aphids for about eight weeks. You can generally purchase them as adults or pupae in mummies. For each square yard, release one to two adults.

  • Introduce them when you see aphids, then proceed with three 1-week intervals
  • Monitor every week for black mummified aphids as an indication of parasitization
  • Introduce more Aphelinus in warmer weather due to potential aphid migration
  • Honeydew production interferes with the aphid’s searching ability
  • Place wasps on leaves mornings and evenings but avoid direct sun
  • Look for black mummies while pruning. When present, keep plants in your greenhouse.
  • Decrease heavy infestations with compatible, soft compounds or ladybird beetles
  • Placing the wasp near an infestation increases the effectiveness
  • Temperatures exceeding 86 degrees Fahrenheit decrease parasitoid activity
  • You can store Aphelinus in the dark at 47 to 50 degrees Fahrenheit for two days, but an immediate release is best.
  • Predatory midges feed on aphids and are generally shipped in vermiculite carriers. Placing the pupae in a warm greenhouse will trigger the emergence of adults.
  • Eggs are laid by females close to aphid colonies. Once hatched, orange midges will attack aphids to feed.

Aphldoletes aphidimyza is a predatory midge and general aphid predator. It will feed on many different species. It can be used alone or combined with parasites for rapid recovery from an aphid infestation. Aphidoletes is most effective where there are large concentrations of the pests. In soil cultures, midge larvae pupate in the ground to create successive generations, eliminating the need for continual introductions. If soil is not the growing medium, continued releases will be needed.

Midge larvae hibernate during the shorter days of September. If growing in fall, use parasites including Aphelinus abdominalis and Aphidius ervi for crops not requiring supplemental light.

For prevention, three midge pupae need to be released when aphids are initially detected for each square yard. Once colonies of aphids are established, you need to release two to nine for each square yard successively three to four times to build a sustained Aphidoletes population. New populations will need to be introduced during the season.

  • Midges can be stored for the short term at 47 to 50 degrees Fahrenheit
  • Humidity needs to be 50 to 90 percent
  • Temperatures need to be 60 to 80 degrees Fahrenheit
  • Plant canopies should be introduced out of direct sunlight
  • Place the predators during the evening or morning close to aphid colonies
  • Examine leaves while pruning for midge larvae
  • Place leaves containing larvae in your greenhouse for completion of the life cycle
  • Aphidius parasitoids and midges cab be used together for aphid prevention
  • Monitor predator effectiveness by looking for shriveled aphids eventually becoming black or brown prior to decay. This will require a 10x hand lens.
Aphid Mummy
Cannabis aphid mummy with exit hole from a parasitoid wasp. PHOTO CREDIT Whitney Cranshaw, Colorado State University, Bugwood.org

CAUTION: The aphid species must be correctly identified prior to ordering predators as the following biocontrol organisms are very host specific. The development of diseases and pests should be monitored from the seedling stage to the end of the cycle weekly. You need to identify and treat hot spots quickly for the prevention of rapid aphid colonization. Biocontrols should be initiated when the aphid population is low.

Melon aphids and green peach aphids can be controlled with Aphidius colemani parasitoid wasps. One egg is laid in each aphid. Once the egg hatches, the larvae feed on the aphid’s internal parts. Upon maturity, an aphid wasp emerges from the shriveled mummy of the aphid body. Consecutively apply 500 units for up to four square yards.

Potato aphids can be controlled with Aphidius ervi. This is a parasitoid wasp with a life cycle and appearance like an aphid, but approximately double the size. When the aphid body is exited by a new adult wasp, a brown shell, referred to as an aphid mummy, is left behind. The following tips are beneficial for using Aphidius:

  • Adult parasitoids should be ordered to prevent parasitizing the larvae
  • Parasitoids should be released when you see aphids
  • Remove all yellow sticky traps prior to release
  • Yellow sticky traps can be used two days each week for whiteflies
  • Blue sticky traps can be used two days each week for thrips
  • Keep humidity levels between 70 and 85 percent
  • Keep temperatures between 65- and 77-degrees Fahrenheit
  • Parasitoids are effective when light levels are low but are sensitive to pesticides
  • You can achieve temporary relief by spraying aphids from your plants using water
  • Install screening vents
  • Remove weeds both outside of and inside your greenhouse
  • All plant debris should be removed from the premises, then destroyed
  • All incoming plant material should be inspected
  • Ornamentals should not be grown in vegetable production areas
  • Ants must be controlled, or they will endanger the parasitoids

Defeat Pests, Mold and Mildew… NATURALLY!

Like it? Share it!