The Peach Potato Aphid (Myzus persicae subsp. persicae) is considered the most significant vector of viral diseases among all aphid species, capable of transmitting over 100 different viruses. This makes it a major concern for growers worldwide. Both nymphs and adults feed by extracting plant sap, which not only depletes nutrients but also disrupts the plant’s hormonal balance. This can lead to stunted growth, leaf deformities, and, if infestations occur early in the season, the death of young plants. In addition to reduced growth, aphid activity can cause defoliation and significantly lower crop yields.

Due to the low protein content of plant sap, aphids must consume large volumes to meet their nutritional needs, excreting the excess sugars as honeydew. This sticky substance coats leaves and fruit, encouraging the growth of black sooty moulds (such as Cladosporium spp.), which contaminate the crop and reduce its market value. The mould also interferes with photosynthesis by blocking light from reaching the leaf surface, further diminishing plant health and productivity. Furthermore, aphid saliva can trigger severe physiological responses in plants, including malformations of growing tips, which further compromise crop quality and yield.

Aphids have a complex life cycle that includes both winged and wingless adult forms and exhibits a wide range of colour variations. During asexual reproduction, young aphids are born as fully developed nymphs that immediately begin feeding on plant sap and grow rapidly. In contrast, sexual reproduction results in the laying of overwintering eggs. In greenhouse environments, reproduction often occurs through parthenogenesis, where unfertilized viviparous females continually produce new generations of female offspring. Aphids undergo four moults before reaching adulthood, shedding white skins at each stage—an indicator of their presence in the crop.

Wingless Green Peach Aphids (Myzus persicae subsp. persicae) can vary in colour, appearing green, white-green, light yellow-green, grey-green, pink, or red. Their bodies have a matte finish, never glossy. Winged forms are more distinctly coloured, with a dark brown to black head and thorax, and an abdomen that ranges from yellow-green to green or even reddish. These winged individuals typically have a dark spot on the abdomen and several transverse black bands across the body. Nymphs destined to become winged adults are often pink or red in colour.

Preventing infestations of the Green Peach Aphid (Myzus persicae subsp. persicae) involves a combination of cultural, physical, and environmental control strategies. Good sanitation is a foundational step—removing plant debris, weeds, and volunteer plants in and around the greenhouse eliminates alternative hosts that aphids might use to establish themselves. It's also important to clean tools, benches, and equipment regularly to prevent accidental transfer of aphids from one area to another.

Exclusion techniques play a crucial role in prevention, particularly in greenhouse environments. Installing fine insect-proof mesh over vents and other openings can help prevent winged aphids from entering. Airlocks or double-door entry systems, and in some cases air curtains, further reduce the chance of pests being introduced when workers or supplies move in and out.

Frequent crop monitoring is essential for early detection. Regularly scouting plants for signs of aphid activity—such as curled or deformed leaves, sticky honeydew, or the presence of white moult skins—allows for timely intervention. Yellow sticky traps can also be used to detect the arrival of winged aphids and monitor overall pressure in the crop.

Cultural practices can make a crop less attractive to aphids. Crop rotation and avoiding the proximity of known aphid host plants can further reduce the risk of infestation.

Mechanical and physical removal methods can also be effective for low-level infestations. Aphids can be knocked off plants with strong water sprays or removed by pruning heavily infested leaves or stems. Careful water management is also beneficial, as overwatering can stress plants and make them more vulnerable to aphid feeding.

Biological control of Green Peach Aphid (Myzus persicae subsp. persicae) can be effectively achieved through the strategic use of several natural enemies, each targeting different life stages of the pest. Successful biocontrol often involves combining multiple agents to provide both rapid knockdown and sustained population suppression. Below are the primary biocontrol products and organisms used against this aphid in greenhouse settings:

Chrysopa (Chrysoperla carnea): Green lacewing larvae are generalist predators that aggressively feed on aphid nymphs and adults. Chrysopa is particularly effective during the early stages of an infestation or in hotspots, providing fast and visible suppression. Since the larvae are mobile and voracious, they are best applied preventively or curatively where aphid clusters are observed.

Aphidalia (Adalia bipunctata): The two-spotted ladybird beetle and its larvae are powerful aphid predators capable of consuming large numbers of aphids daily. Aphidalia is best suited for localized outbreaks, especially in crops where aphids are well-exposed and not deeply hidden. Adults are long-lived and provide longer-term control when aphid populations are sustained.

Aphipar (Aphidius colemani): This parasitic wasp targets younger nymphs of Green Peach Aphid. After laying an egg inside the aphid, the larva develops and eventually mummifies the host. Aphipar is most effective when aphid pressure is low to moderate and is ideal for preventive releases. It performs best in warm, stable greenhouse climates and is often used in combination with predators for broader control.

Aphipar-M (Aphidius matricariae): Closely related to Aphipar, this species is also a parasitoid but has a slightly different host preference and may perform better under certain environmental conditions or when targeting the new Myzus persicae strain. It is well-suited for integration with other parasitoids or predators in a mixed-release program.

Aphidend (Aphidoletes aphidimyza): This predatory midge targets a wide range of aphid species, including Green Peach Aphid. The larvae are highly effective at killing aphids by injecting digestive enzymes and consuming them. Aphidend works best in warm, humid environments and is ideal for curative control when aphid colonies are already established.

When used together in an Integrated Pest Management (IPM) strategy, these biocontrol agents can provide robust and sustainable control of Green Peach Aphid. Preventive releases of parasitoids like Aphipar or Aphipar-M can help maintain low pest levels, while predators like Chrysopa or Aphidend provide rapid knockdown during outbreaks. Strategic rotation or combination of these products, based on crop type, greenhouse conditions, and aphid pressure, yields the best results.