Greenhouse Potato Aphid
Macrosiphum euphorbiae
📖 Description
Macrosiphum euphorbiae, the potato aphid, is one of the largest aphid species affecting polyhouse crops worldwide and a major pest of polyhouse tomato, sweet pepper, and rose in India. The species is native to North America but has become cosmopolitan through the international trade in greenhouse plant material. It is anholocyclic (continuous parthenogenesis) in polyhouse conditions, so a single mated female can found a colony of 10,000+ descendants within 4 weeks. The species is highly polyphagous (>200 plant species) and transmits more than 50 plant viruses, including Potato Leafroll Virus (PLRV) and Potato Virus Y (PVY) — making it a chronic reservoir for viral disease in polyhouse and field crops alike. Unlike the green peach aphid (Myzus persicae), M. euphorbiae does not develop insecticide resistance as rapidly, making it more amenable to IPM-based management with selective aphicides and biological control. Estimated annual losses to the Indian polyhouse industry from M. euphorbiae alone exceed ₹80 crore, with most losses concentrated in Maharashtra and Karnataka.
⚠️ Symptoms to watch for
- Curling and distortion of tender polyhouse tomato leaves, sticky honeydew on lower leaves with attendant sooty mould, scarred and deformed flowers in rose, transmission of more than 50 plant viruses (including Potato Leafroll Virus, Potato Virus Y, Cucumber Mosaic Virus), and reduced yield in heavily infested polyhouse tomato crops. Because the species is highly polyphagous and reproduces year-round in polyhouses without an overwintering sexual phase, populations can build to damaging levels within 2–3 weeks of initial colonisation.
🩹 Treatment
- Monitor with yellow sticky traps at 20/ha and inspect lower leaves weekly for colony initiation. Conserve parasitoid wasps (Aphidius spp.) and predatory midges (Aphidoletes aphidimyza) — they are the most effective natural control. Spray neem oil 1 % or azadirachtin 1 % (2 ml/L) at the first sign of colony formation. If infestations exceed 20 aphids/leaf on polyhouse tomato, apply imidacloprid 17.8 SL @ 0.3 ml/L or pymetrozine 50 WG @ 0.3 g/L (selective to aphids, safe to predators). Always rotate neonicotinoids with other modes of action to delay resistance.
🌿 Organic treatments
- Yellow sticky traps @ 20/ha; neem oil 1 %; azadirachtin 1 % (2 ml/L); release of Aphidius colemani parasitoids at 2 wasps/m²; release of Aphidoletes aphidimyza predatory midges at 1 midge/m²; release of Chrysoperla zastrowi sillemi lacewing larvae at 5 larvae/m²; soap spray (potassium oleate 1 %); Lecanicillium lecanii 1×10^8 cfu/mL @ 5 g/L during humid weather.
🧪 Chemical treatments
- Imidacloprid 17.8 SL @ 0.3 ml/L; acetamiprid 20 SP @ 0.2 g/L; thiamethoxam 25 WG @ 0.2 g/L; pymetrozine 50 WG @ 0.3 g/L (selective, parasitoid-safe); spirotetramat 240 SC @ 0.4 ml/L (translaminar); flonicamid 50 WG @ 0.3 g/L (selective).
🛡️ Prevention
- Screen polyhouse vents with 50-mesh insect screen. Inspect all incoming transplants and quarantine for 1 week before planting. Maintain weed-free 10 m perimeter around the polyhouse — weeds serve as reservoirs. Avoid continuous tomato cropping — rotate with sweet pepper or leafy greens between cycles. Avoid overuse of pyrethroids and organophosphates that destroy parasitoids and predatory midges — their loss is the single most common trigger for aphid outbreaks. Use reflective silver mulch on polyhouse beds to repel alate colonisation. Maintain balanced nitrogen — high-N tissue is preferentially colonised.
🪴 Affected plants
- Polyhouse tomato, sweet pepper, cucumber, potato, eggplant, strawberry, rose, chrysanthemum, gerbera, and many ornamentals. In India it is a major pest of polyhouse tomato and rose in Maharashtra (Pune), Karnataka (Bengaluru), Telangana (Hyderabad), and Himachal Pradesh (Solan, Kullu — under protected cultivation).
🦋 Natural predators
- Parasitoid wasps (Aphidius colemani, Aphidius ervi, Lysiphlebus testaceipes), predatory midges (Aphidoletes aphidimyza), ladybird beetles (Coccinella transversalis, Menochilus sexmaculatus, Hippodamia variegata), green lacewing larvae (Chrysoperla zastrowi sillemi), and entomopathogenic fungi (Lecanicillium lecanii, Beauveria bassiana).
🌱 Host plants
- Polyhouse tomato, sweet pepper, cucumber, potato, eggplant, strawberry, rose, chrysanthemum, gerbera, and 200+ other plant species across 40+ families.
🔄 Lifecycle
- Anholocyclic (continuous parthenogenesis) in polyhouse conditions.
- Viviparous female produces 40–80 nymphs over 10–20 days; nymphs pass through 4 instars in 7–12 days; adult lifespan 20–40 days; up to 30 generations per year in polyhouse conditions.
- Winged alates develop when colonies become crowded or when host quality declines.
📅 Season
- Active year-round in polyhouse conditions; populations peak during the cool dry months (October–March) when polyhouse vents are partially closed and humidity is favourable.
🔎 Appearance
- Adult is a large, spindle-shaped, pink to green or yellowish-green aphid with long black cornicles (siphunculi) longer than the cauda, long black legs, and prominent red eyes.
- Antennae are longer than the body.
- Winged alates have a black thorax and darker body markings; wingless parthenogenetic females dominate the colonies.
- Nymphs are smaller, paler, and slightly more elongate than adults of the same colour form.
- The species is extremely variable in colour — pink, green, and yellow forms can coexist in the same colony.
💥 Damage level
- Moderate
🔁 Reproduction rate
- Fast
🗺️ Geographic regions
- Indian Subcontinent (Maharashtra
- Karnataka
- Telangana
- Tamil Nadu
- Himachal Pradesh polyhouse tracts)
- cosmopolitan in temperate
- subtropical
- and tropical greenhouse regions worldwide.
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