Aphids – A Key Spring Pest of Greenhouse Crops

​Texas A&M AgriLife Research and Extension Center
Overton, TX

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Spring represents a critical period for greenhouse crop production because increasing temperatures and the availability of tender plant growth create favorable conditions for the development of several insect pests. Among these, aphids are one of the most common and economically important pests encountered during this time. Aphids are small, soft-bodied, winged or wingless, phloem-feeding insects.

Aphids feed by piercing plant tissues and sucking plant sap. Their feeding can cause a variety of symptoms, including curled or distorted leaves, stunted plant growth, and reduced plant vigor. In addition to direct feeding damage, aphids excrete a sticky substance known as honeydew. Honeydew can accumulate on leaves and stems, leading to the growth of sooty mold fungi that reduce the aesthetic quality and market value of ornamental plants. Some aphid species can also transmit plant viruses, making early management even more important.

Many aphid species reproduce through parthenogenesis and give birth to live nymphs, allowing populations to increase exponentially within a short period. As a result, even low initial infestations can quickly develop into significant pest outbreaks if not detected and managed early through regular monitoring and timely intervention. Early detection is the key to effective aphid management. Growers should inspect plants frequently, especially new growth and the undersides of leaves, where aphids often congregate. Yellow sticky cards can only help to monitor the winged aphids, but not the wingless adults.

An integrated pest management (IPM) approach is the most effective strategy for managing aphids. Cultural practices, such as removing heavily infested plant material and managing weeds inside and around the greenhouse, can help reduce aphid populations. Maintaining good sanitation practices and carefully inspecting incoming plant material can also prevent new infestations.

Biological control can be an effective tool in greenhouse systems. Natural enemies such as lady beetles, lacewings, and parasitic wasps can help suppress aphid populations when released at appropriate times. High pressure wash water spray can reduce the population of aphids. When aphid populations reach damaging levels, insecticides may be necessary. Growers should select products carefully and rotate insecticides with different modes of action to reduce the risk of resistance development.

By combining monitoring, cultural practices, biological control, and responsible pesticide use, greenhouse growers can successfully manage aphids and protect the quality and productivity of their crops during the spring season.

Figure: Bean aphid (A), Crape myrtle aphid (B), and Green peach aphid (C). Photo courtesy: Rafia Khan