Aphids are small insects from the Aphidoidea family of insects. You might also hear them called “greenfly” or “blackfly.” However, the 5000 known species of aphid come in a variety of colors.
Aphids are one of the most destructive insects in the temperate region. These sap-sucking insects only live for one month. Unfortunately, they can do a lot of damage during that month.
We’ve explained how quickly aphids multiply and the type of damage they cause. We’ve also listed several specific kinds of aphids, what they eat, and the types of damage they cause.
Aphid Multiplication Problems
Aphids do a great deal of damage because they multiply quickly. When an infected leaf becomes too crowded, an aphid will develop wings to fly from plant to plant to look for a suitable host. Each aphid can produce 40-60 offspring and lay several aphid eggs or wingless nymphs on each plant upon which they land.
Aphids reach sexual maturity in 7-10 days. They are usually all born female and can reproduce asexually with no need for male fertilization. They are also a parthenogenetic species that can be born pregnant, which allows for telescoping generations.
Multiply 60 by 60 a few times every 7-10 days, and you can start to see how quickly aphids can get out of hand in your garden.
Aphids are a pest for agriculture, fiber industries, forestry, and home gardeners. Some aphid species feed on just one type of plant, others have a life cycle that involves two species of plants, while others are generalists that colonize many plant types.
Aphids can damage plants in a variety of ways. These garden pests weaken plants by sucking their sap, transmit plant viruses, and leave behind honeydew secretions that feed sooty molds.
Sap-Sucking Side Effects
Aphids infest the undersides of tender terminal leaves. Then, they use their piercing, sucking mouthparts to feed on plant sap.
For many plants, sap-sucking just makes the leaves wilt or turn yellow.
However, other plants are more sensitive to aphid saliva, and their leaves pucker or become severely distorted. Some plants will produce malformed fruit or flowers after aphids feed on them.
Aphid Virus Transmission
Aphids can be a vector for spreading viruses from one plant to another. If an aphid has a plant virus on its mouthparts, it only needs to probe a plant for a few seconds or minutes to infect another plant.
Aphids produce a sticky, sugary liquid waste called honeydew which can attract other insects such as ants.
Sooty mold grows on and decomposes honeydew as their primary source of nutrition. Sooty mold doesn’t feed on the plant itself. However, when sooty mold covers leaves, it blocks sunlight and prevents photosynthesis.
You can expect that any plant that has a problem with honeydew may eventually find itself host to sooty mold as well.
Sometimes scientific names can be confusing here are some articles on types of aphids you may encounter around your home:
- Getting Rid of White Aphids
- Controlling Woolly Aphids
- Killing Black Aphids
- Oleander Aphids, Rose Aphids and Mandevilla Aphids
Thousands of types of aphids exist. However, these are some of the most common ones.
Black bean aphids have olive-green to black bodies. They colonize beans, corn, sugar beets, lamb’s quarters, and pigweed during the summer. They overwinter as eggs on burning bushes and snowball bushes.
Black bean aphid damage you might notice includes:
- Leaf distortion, wilting, curled leaves, and yellowing
- Dense Aphid populations on the undersides of leaves
- White cast-off skins on the underside of leaves from previous generations
- Black sooty mold
Grape Phylloxera Aphid (Daktulosphaira vitifoliae)
Grape phylloxera aphids can be various colors, including yellow, yellowish-green, olive green, light brown, brown, or orange. They feed on the roots of both wild and cultivated grapes.
The type of damage you will notice if grape phylloxera aphids infect your grape roots includes:
- Swollen and yellowish roots
- Dead spots on roots from secondary fungal infections
- Weakened or stunted vines
- Less fruit
More on Daktulosphaira vitifoliae
Green aphids are usually pale green but can sometimes be pinkish. They are one of the most common aphids found on peppers.
Green peach aphids can damage pepper plants in the following way:
- Yellowing and curling of leaves downwards and inward from their edges
- Transmission of pepper potyviruses and cucumber mosaic cucumovirus
Related: Getting Rid of Aphids on Succulents
Hop Aphid (Phorodon humili)
Hop aphids are pale white to green. They overwinter as eggs on Prunus species, including plums, peaches, nectarines, apricots, cherries, and almonds. In spring, they feed on their original Prunus host and then travel to hop plants.
Hop aphid damage includes:
- Curled and wilted leaves
- Defoliation from heavy infestation
- Wilting and browning of hop cones
- Sooty mold
- Viruses including carlaviruses
More on Phorodon humili
Lily Aphid (Neomyzus circumflexus)
Lily aphids range from white to pale yellow and bright green. They are polyphagous, feeding on various plants, including ferns, herbs, climbers, shrubs, and trees. In temperate climates, they mainly feast on greenhouse plants.
Damage from lily aphids include:
- Deformed, curled, and wilted leaves
- Leaf galls
More on Neomyzus circumflexus
Melon Aphid (Aphis gossypii)
Melon aphids are either yellowish-green or a dark green that appears black under low light. They feed on cucurbits, cotton, okra, hops, strawberries, asparagus, citrus, catalpa, violets, hydrangeas, begonias, beans, spinach, tomatoes, ground ivy, gardenias, and clover.
Melon aphid damage includes:
- Growth distortion
- Decreased crop yield and quality
- Prematurely ripened fruit
- Fruit covered with aphids, cast skins, and honeydew
- Transmission of plant viruses including lily rosette, lily symptomless diseases, citrus quick decline, onion yellow dwarf, and cucumber mosaic
More on Melon Aphids – Aphis gossypii
Norway Maple Aphid (Periphyllus lyropictus)
Norway maple aphids are yellowish with brown dorsal markings, usually with a stripe from the head to the thorax and a v-shaped mark on the dorsal abdomen. They lay eggs and feed on maple trees.
Damage Norway maple aphids inflict on maple trees include:
- Minor plant-tissue damage from piercing sap-sucking
- Sooty mold
More on Periphyllus lyropictus
Potato Aphid (Macrosiphum solanifolii)
Potato aphids can be red or green. Infestation colonies can include a combination of both colors of aphids. They feed on potatoes and hundreds of other plants, including eggplants, tomatoes, lettuce, turnips, spinach, and kale.
Damage from extreme potato aphid infestation can include:
- Distortion of leaves and terminals
Spruce Aphids (Elatobium abietinum)
Spruce aphids are green. They closely match the color of their favorite food: spruce tree needles. They usually feed on older needles. However, because they are wingless, they may move to newer branches during a population breakout.
The type of damage you can expect from spruce aphids include:
- Yellowing, browning, and dropping of needles
More on Elatobium abietinum
Western Aster Root Aphid (Anuraphis middletonii)
Western aster root aphids lay tiny green eggs, but adults are light yellow and more transparent as nymphs. They feed on the roots of herbaceous perennials in the summer and Populus trees such as aspens and cottonwoods in the fall.
The types of damage western aster root aphids cause in herbaceous perennials include:
- Leaf wilting
- The top of the plant falling off as a result of heavy infestations
- Spreading of the watermelon mosaic virus
Damage western aster root aphids do to Populus trees are not as severe and include:
- Leaf galls
- Premature leaf drop
More on Anuraphis middletonii
Final Thoughts on Aphids
There’s no way we could cover all the aphids you might find in your garden, but at least you know now that wilting plants, deformed fruit, honeydew, and sooty mold are signs you might have aphids hiding under your leaves.
Aphids multiply quickly and can seriously damage plants when they suck sap, spread viruses, or when their honeydew attracts sooty mold. Early identification can be vital to get rid of infestations, preventing severe damage, and preventing spread to other plants of the same or different species.