Wild Mustard Aphid (Turnip Aphid)
Lipaphis pseudobrassicae
📖 Description
Lipaphis pseudobrassicae — the Wild Mustard Aphid or Turnip Aphid — is one of the most damaging insect pests of Indian mustard and rapeseed cultivation, with economic significance centred on the mustard belts of Rajasthan (Bharatpur, Alwar, Kota — India’s largest mustard-growing state, ~2.5 million ha), Madhya Pradesh (Mandsaur, Ujjain, Ratlam), Uttar Pradesh (Agra, Mathura, Aligarh), and Haryana (Hisar, Sirsa, Mahendragarh). India is the world’s third-largest rapeseed-mustard producer (~9 million tonnes from ~6 million ha), with mustard oil being the second-most-consumed edible oil in India after palm oil (annual consumption ~2.5 million tonnes). The pest is native to Europe but has spread worldwide through the international Brassica seed trade — it was first reported in India in the 1970s and has since become established as the dominant aphid pest of Indian mustard, displacing the cabbage aphid (Brevicoryne brassicae) in most mustard-growing regions. The pest’s biology makes it particularly damaging: (1) rapid parthenogenetic reproduction — females give birth to 80–120 live female nymphs without mating, allowing populations to multiply 30-fold per generation; (2) concealed feeding on the undersides of leaves and inside inflorescences — protected from contact insecticides; (3) wide host range (all Brassica crops and >30 Cruciferous weed species) — survives on wild mustard (Sinapis arvensis) on orchard floors, field margins, and irrigation bunds between mustard crops; (4) efficient virus vectoring — both non-persistent (TuMV, CaMV) and persistent (Cabbage Black Ring Spot Virus) transmission; and (5) high insecticide resistance — the pest has documented resistance to organophosphates (dimethoate, monocrotophos), pyrethroids, and even neonicotinoids in some Rajasthan populations. The economic impact is severe: heavy infestations can reduce mustard seed yield by 30–50% (₹8,000–15,000 per ha loss) and reduce oil content by 5–10% — for a typical Rajasthan mustard grower cultivating 2 ha of mustard, a severe L. pseudobrassicae infestation can wipe out ₹20,000–30,000 of annual income. Beyond direct feeding damage, the pest is the principal vector of Turnip Mosaic Virus (TuMV) — the most damaging virus of Indian mustard — which can cause complete crop loss in infected fields. The IPM approach recommended by ICAR-DRMR (Directorate of Rapeseed-Mustard Research, Bharatpur) combines early sowing (escaping peak aphid migration), weed reservoir management (eliminating wild mustard and Cruciferous weeds on field margins), yellow sticky trap monitoring, threshold-based neonicotinoid or flonicamid application (preserving beneficials), biological control (Aphidius colemani releases), crop rotation, and balanced nutrition. The single most effective prevention measure is eliminating wild mustard (Sinapis arvensis) and other Cruciferous weeds on orchard floors, field margins, and irrigation bunds — these weeds serve as the primary reservoir from which aphids migrate to mustard crops each season.
⚠️ Symptoms to watch for
- Adults and nymphs cluster on the undersides of leaves and on inflorescences, sucking phloem sap.
- Feeding causes leaf curling, yellowing, and distortion
- heavy infestation causes inflorescence stunting, flower drop, and pod abortion.
- Honeydew excretion promotes sooty mould growth on leaves — reducing photosynthesis.
- The pest also vectors Turnip Mosaic Virus (TuMV), Cauliflower Mosaic Virus (CaMV), and Cabbage Black Ring Spot Virus — both non-persistent and persistent transmission.
- Heavy infestations can reduce mustard seed yield by 30–50% (₹8,000–15,000 per ha loss) and reduce oil content by 5–10%.
🩹 Treatment
- Apply imidacloprid 17.8 SL at 0.3 ml/L — systemic neonicotinoid.
- Apply thiamethoxam 25 WG at 0.4 g/L — systemic neonicotinoid.
- Apply acetamiprid 20 SP at 0.4 g/L — systemic.
- Apply flonicamid 50 WG at 0.4 g/L — selective aphicide
- preserves beneficials.
- Apply pymetrozine 50 WG at 0.4 g/L — selective aphicide.
- Apply diafenthiuron 50 WP at 1 g/L — mitochondrial ATP synthase inhibitor.
- Apply azadirachtin 1% at 2 ml/L — antifeedant.
- Release Aphidius colemani parasitoid wasps at 50,000/ha.
- Release Chrysoperla zastrowi sillemi lacewing larvae at 10,000/ha.
- Use yellow sticky traps at 8–12 per ha.
- Apply NSKE 5%.
- Avoid pyrethroids (broad-spectrum, kill beneficials).
🌿 Organic treatments
- Azadirachtin 1% (NeemAzal) — 2 ml/L
- antifeedant and growth disruptor
- OMRI-listed.
- Neem seed kernel extract (NSKE) 5% — repels aphids.
- Verticillium lecanii (Lecanicillium lecanii, 1×10⁹ CFU/g) at 5 g/L — entomopathogenic fungus.
- Beauveria bassiana (1×10⁹ CFU/g) at 5 g/L — entomopathogenic fungus.
- Garlic + chilli + ginger extract (3% each) — traditional Indian repellant.
- Yellow sticky traps at 8–12 per ha — mass-trap alates.
- Release Aphidius colemani parasitoid wasps at 50,000/ha — most effective biological control.
- Release Chrysoperla zastrowi sillemi lacewing larvae at 10,000/ha.
- Release Hippodamia variegata ladybird beetles at 5,000/ha.
- Avoid broad-spectrum insecticides — they kill natural enemies and trigger aphid population resurgence.
🧪 Chemical treatments
- Imidacloprid 17.8 SL (Confidor) — 0.3 ml/L
- neonicotinoid
- systemic
- long residual (21–28 days)
- 7-day PHI.
- Thiamethoxam 25 WG (Actara) — 0.4 g/L
- neonicotinoid
- systemic.
- Acetamiprid 20 SP (Mospilan) — 0.4 g/L
- neonicotinoid
- systemic
- less bee-toxic than imidacloprid.
- Flonicamid 50 WG (Fulfill) — 0.4 g/L
- selective aphicide
- feeding inhibitor
- preserves beneficials.
- Pymetrozine 50 WG (Plenum) — 0.4 g/L
- selective aphicide
- feeding inhibitor.
- Diafenthiuron 50 WP (Polo) — 1 g/L
- mitochondrial ATP synthase inhibitor.
- Spirotetramat 240 SC (Movento) — 0.4 ml/L
- lipid synthesis inhibitor
- systemic
- excellent against nymphs.
- Dimethoate 30 EC — 1 ml/L
- organophosphate
- systemic — use only when aphid populations exceed economic threshold.
- Avoid pyrethroids (lambda-cyhalothrin, deltamethrin) — broad-spectrum, kill beneficials.
- Rotate IRAC groups to prevent resistance.
🛡️ Prevention
- Manage wild mustard and Cruciferous weeds on orchard floors, field margins, and irrigation bunds — these are the primary reservoirs from which aphids migrate to mustard crops.
- Practise early sowing (early October in north India) — escapes peak aphid migration (November–December).
- Use yellow sticky traps at 8–12 per ha from crop emergence to monitor alate (winged) aphid migration.
- Release Aphidius colemani parasitoid wasps preventively at 50,000/ha — most effective biological control.
- Maintain balanced nutrition — excess nitrogen promotes soft, aphid-susceptible growth.
- Apply threshold-based insecticide sprays (50 aphids per plant) rather than calendar sprays — preserves natural enemies.
- Practise crop rotation with non-Brassica crops (cereals, legumes) for at least 1 year between mustard crops — breaks the aphid lifecycle.
- Rogue out virus-infected plants immediately — the aphid vectors TuMV, CaMV, and Cabbage Black Ring Spot Virus.
- Plant trap crops of early-sown mustard around the perimeter of main mustard fields — alates congregate on the trap crop and can be sprayed there, sparing the main crop.
- Plant windbreaks (maize, sorghum) around mustard fields — aphids are weak fliers and windbreaks reduce migration.
🪴 Affected plants
- Brassica crops — mustard (Brassica juncea — Indian rai), rapeseed (B. rapa — toria, yellow sarson, brown sarson), cabbage (B. oleracea var. capitata), cauliflower (B. oleracea var. botrytis), radish (Raphanus sativus), turnip (B. rapa var. rapa).
- Cruciferous weeds — Lepidium draba (hoary cress), Capsella bursa-pastoris (shepherd's purse), Sisymbrium irio (London rocket).
- Wild mustard (Sinapis arvensis) is the principal reservoir host on orchard floors and field margins.
- In India, the pest is most damaging in mustard/rapeseed belts of Rajasthan (Bharatpur, Alwar, Kota), Madhya Pradesh (Mandsaur, Ujjain, Ratlam), Uttar Pradesh (Agra, Mathura, Aligarh), and Haryana (Hisar, Sirsa, Mahendragarh).
🦋 Natural predators
- Aphidius colemani (braconid parasitoid wasp — the most effective biological control agent; commercially reared by NBAIR Bangalore; release rate 50,000/ha).
- Diaeretiella rapae (braconid parasitoid wasp — most common natural enemy of brassica aphids; natural parasitism rates of 30–50% in unsprayed mustard crops).
- Aphidius matricariae (braconid parasitoid wasp).
- Chrysoperla zastrowi sillemi (green lacewing — predator of aphid nymphs; release rate 10,000/ha).
- Coccinella septempunctata (7-spot ladybird — predator).
- Hippodamia variegata (ladybird beetle — predator).
- Menochilus sexmaculatus (ladybird beetle — predator).
- Syrphus corollae (hoverfly — predatory larvae).
- Aphidoletes aphidimyza (predatory midge).
- Natural enemies are most effective in unsprayed mustard crops — commercial mustard crops typically receive 2–4 insecticide applications per season that suppress natural enemies.
🌱 Host plants
- Mustard (Brassica juncea — Indian rai — primary host).
- Rapeseed (B. rapa — toria, yellow sarson, brown sarson), cabbage (B. oleracea var. capitata), cauliflower (B. oleracea var. botrytis), radish (Raphanus sativus), turnip (B. rapa var. rapa).
- Cruciferous weeds — wild mustard (Sinapis arvensis — primary reservoir host on orchard floors and field margins), Lepidium draba (hoary cress), Capsella bursa-pastoris (shepherd's purse), Sisymbrium irio (London rocket), Nasturtium officinale (watercress).
🔄 Lifecycle
- Egg (rare in tropical India — parthenogenetic reproduction predominates) → Nymph (4 instars) → Adult.
- In India, reproduction is entirely parthenogenetic (viviparous) — females give birth to live female nymphs without mating.
- Each female produces 80–120 nymphs over her 15–25 day adult lifespan.
- Nymphs feed and moult 4 times over 6–9 days, reaching maturity.
- Total cycle 8–12 days at 25 °C; 18–25 overlapping generations per year in Indian mustard-growing belts.
- In northern India (Rajasthan, Haryana, Punjab), the pest overwinters as parthenogenetic females on wild mustard and Cruciferous weeds — there is no sexual reproduction or egg stage in Indian conditions.
- In temperate regions (Europe, North America), the aphid alternates between primary host (Prunus species for overwintering eggs) and secondary hosts (Brassica crops for summer parthenogenetic generations) — but in India, the parthenogenetic phase is continuous year-round on mustard and Cruciferous weeds.
📅 Season
- Peak activity November–February (rabi mustard crop in Rajasthan, Madhya Pradesh, Uttar Pradesh, Haryana) when daytime temperatures are 18–28 °C.
- Lower activity March–April (high temperatures exceed 35 °C, suppressing reproduction).
- No activity May–September (hot dry summer — pest survives as parthenogenetic females on wild mustard and Cruciferous weeds in moist microhabitats).
- Pest populations build up rapidly in November–December (alate migration from weed reservoirs to mustard crops) and peak in January–February (peak damage period).
🔎 Appearance
- Small, oval, pale yellowish-green to greyish-green aphid 1.4–2.2 mm long, often lightly dusted with white waxy powder.
- Body is somewhat flattened dorso-ventrally.
- Siphunculi (cornicles) are dark, tubular, slightly swollen at the apex, and shorter than the cauda — a key feature distinguishing it from other brassica aphids.
- Antennae are shorter than the body.
- Legs are pale with dark apices.
- Winged forms (alates) have a dark thorax and transparent wings with dark veins.
- Nymphs resemble adults but are smaller, paler, and wingless.
- The species is morphologically similar to the cabbage aphid (Brevicoryne brassicae) but lacks the dense grey waxy bloom.
💥 Damage level
- Severe
🔁 Reproduction rate
- Fast
🗺️ Geographic regions
- Indian Subcontinent, South Asia, cosmopolitan.
- In India: Rajasthan (Bharatpur, Alwar, Kota, Sawai Madhopur, Dholpur), Madhya Pradesh (Mandsaur, Ujjain, Ratlam, Neemuch), Uttar Pradesh (Agra, Mathura, Aligarh, Etawah, Mainpuri), Haryana (Hisar, Sirsa, Mahendragarh, Bhiwani), Punjab (Bathinda, Muktsar, Faridkot), Bihar (Arrah, Buxar), West Bengal (Burdwan, Nadia, Murshidabad), Assam (Nagaon, Morigaon).
- Pest is cosmopolitan — found in all Brassica-growing regions of the world
- particularly damaging in tropical and subtropical mustard-growing belts.
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