Opium Poppy Capsule Weevil
Ceutorhynchus maculaalba
📖 Description
Ceutorhynchus maculaalba, the opium poppy capsule weevil, is a specialist pest of Papaver somniferum that causes dual losses — both latex (the legally controlled opium gum of commerce) and seed — making it the most economically important entomological threat to India’s licit opium industry. India is one of only 12 countries licensed by the International Narcotics Control Board to produce opium for pharmaceutical use, and the weevil causes estimated annual losses of ₹80–120 crore to licensed farmers in MP and Rajasthan. The weevil has a single annual generation synchronised to the poppy capsule stage: adults emerge from soil or crop residues in February–March, mate, and females bore into green capsules with their rostrum to oviposit; larvae feed internally on the developing seed capsule for 25–35 days before pupating in the soil. Because the latex is the controlled substance, insecticide choice is restricted to those that do not leave detectable residues above pharmacopoeial limits — making this an unusually challenging pest to manage.
⚠️ Symptoms to watch for
- Punctures on green capsules where adults feed and oviposit, withering and premature drying of punctured capsules, latex leakage that reduces gum yield by 25–40 %, and bored cavities inside the capsule where larvae consume developing seeds.
- Heavily infested fields show patchy capsule maturation and a characteristic 'shot-hole' appearance on drying capsules.
- Seed yield losses of 15–35 % are common in unprotected fields.
🩹 Treatment
- Monitor adult emergence with yellow sticky traps at 10/ha from early capsule formation.
- Spray neem oil 2 % or azadirachtin 1 % (2 ml/L) at the early capsule stage to deter oviposition.
- If infestations exceed 5 adults per 10 plants, apply deltamethrin 2.8 EC @ 1.0 ml/L or lambda-cyhalothrin 5 EC @ 0.5 ml/L during evening hours when adults are most active.
- Repeat after 10 days if necessary.
- Always observe the mandatory 7-day pre-harvest interval for latex collection.
🌿 Organic treatments
- Neem oil 2 % emulsion at capsule formation
- azadirachtin 1 % (2 ml/L)
- Beauveria bassiana 1×10^8 cfu/mL @ 5 g/L sprayed on capsules
- collection and destruction of infested capsules
- deep ploughing after harvest to expose overwintering adults to birds.
🧪 Chemical treatments
- Deltamethrin 2.8 EC @ 1.0 ml/L
- lambda-cyhalothrin 5 EC @ 0.5 ml/L
- acephate 75 SP @ 0.75 g/L
- quinalphos 25 EC @ 1.5 ml/L
- spinosad 45 SC @ 0.2 ml/L (compatible with the Central Bureau of Narcotics approved list).
🛡️ Prevention
- Follow mandatory crop rotation with wheat, mustard, or coriander for at least 2 years — overwintering adults emerge from the same field each season.
- Destroy infested crop residues by burning after latex collection.
- Avoid late sowing (after mid-November), which coincides capsule formation with peak adult activity.
- Use only certified, Narcotics-controlled seed
- commercial seed trade is restricted and often carries hidden infestation.
- Maintain field sanitation — wild Papaver spp. and Argemone mexicana act as reservoirs.
🪴 Affected plants
- Opium poppy (Papaver somniferum) is the primary host.
- In India, severe in the licensed poppy tracts of Madhya Pradesh (Mandsaur, Neemuch), Rajasthan (Chittorgarh, Kota), and Uttar Pradesh (Bareilly, Barabanki).
🦋 Natural predators
- Ground beetles (Carabidae) that prey on larvae dropping to the soil for pupation
- parasitoid wasps (Pteromalidae) that attack eggs and young larvae inside the capsule
- spiders and predatory bugs that take adults on foliage.
🌱 Host plants
- Opium poppy (Papaver somniferum) is the sole economic host
- wild Papaver spp. and Argemone mexicana are occasional reservoirs.
🔄 Lifecycle
- Single annual generation.
- Adults emerge from overwintering sites in soil/crop residue in February–March; mated females bore into green capsules and lay 1–4 eggs per capsule; larvae feed internally on seed for 25–35 days, then drop to the soil and pupate at 5–10 cm depth; new adults emerge in April–May, feed briefly, then enter summer aestivation/overwintering in soil.
📅 Season
- Active February–April in the Indian opium tract, peaking during the capsule-formation to latex-lancing window (mid-March to mid-April).
🔎 Appearance
- Small, compact, grey-brown weevil with a distinctive elongated, slightly curved rostrum and dense grey-white scales covering the elytra, giving it a mottled appearance.
- A pale, irregular white spot near the centre of each elytron gives the species its name (macula-alba = 'white spot').
- Legs are dark reddish-brown; antennae are geniculate and clubbed.
- Larvae are legless, white, C-shaped grubs with a brown head capsule, found feeding inside poppy capsules.
💥 Damage level
- High
🔁 Reproduction rate
- Slow
🗺️ Geographic regions
- Indian Subcontinent (MP, Rajasthan, UP licit opium tracts)
- Central Asia (Afghanistan, Pakistan, Turkey)
- Eastern Europe
- China.
Have an Insect to Identify?
Upload or take a photo of an insect on your plant and our AI will identify it and recommend treatments.
📷 Diagnose from Image