During this time of the growing season, it is common to observe aphids on garden plants, including peppers. However, when dense aphid populations are present, they can reduce pepper yields and cause rapid plant health decline.
The presence of large aphid populations on peppers can be determined by simply examining the plants for the aphids. Some indicators of an infestation include shiny plants and the subsequent growth of sooty mold due to the presence of honeydew, wilting, leaf curling and increased ant activity. In addition to feeding injury, aphids are capable of vectoring plant viruses that further reduce plant health. The three most common species of aphids that are capable of infesting peppers in South Dakota are the green peach aphid, potato aphid and foxglove aphid.
Aphid Identification
Green Peach Aphids
Like their name implies, these wingless nymph and adult aphids are green to yellow-green in color. However, there have been observations of green peach aphids that are pink.
They have green cornicles (tailpipes) that have darker tips. The last leg segments are black (Figure 1).
Potato Aphids
The wingless nymph and adult aphids are mainly green in color but may also be pink or a pink and green mottled color.
Their cornicles (tailpipes) have black tips and are very long. The last leg segments are black. Their antennae are black near the tips (Figure 2). As adults, they are the largest of the three species.
Foxglove Aphids
The wingless nymph and adult aphids are green in color.
They have green cornicles (tailpipes) that have black tips. The last leg segments are black. Their antennae may have small black segments and are black near the tips (Figure 3).
Management
Typically, aphid infestations in peppers will not require insecticide management. Squishing the aphids without damaging the leaves may be effective. Also, the application of soapy water to the undersides of the leaves may reduce the aphid populations. However, if an average of more than five aphids per leaf is present after fruit set, an insecticide may be necessary. When applying an insecticide, make sure to select one with the pest species on the label. There are resistance issues known with green peach aphids so monitor plants for aphid populations after application. As always, read the insecticide label and follow the listed pre-entry and pre-harvest intervals.
To reduce future aphid populations, there is evidence that placing aluminum foil or reflective plastic mulch around the base of the plants on the ground is effective. These strategies reduce the winged aphids’ ability to find the plants. The contrast between bare ground and the green plants is how the aphids find the host plants. By making it harder to find the hosts, you can effectively reduce the aphid infestations.
