DAR ES SALAAM: On 7 November 2026, Geoffrey Kirenga, Chief Executive Officer of the AGCOT Centre (Agricultural Growth Corridors of Tanzania), shared photographs of avocado fruit pierced and scarred by insect damage with a blunt warning in Kiswahili: “Madhara yake. Ni mharibifu sana. Tuwe makini tulinde mazao yetu.” In English: “This is the damage it does. It is very destructive. Let us be vigilant and protect our crops.”
The pest at the centre of the warning is the large avocado seed weevil, Heilipus lauri, known in Kiswahili as fukusi wa parachichi or fukusi mkubwa wa mbegu ya parachichi. It is a specialist pest of avocado that destroys fruit from the inside, and it is one of the pests that importing countries watch most closely.
The timing of the warning matters. Tanzania’s avocado industry has never been bigger. According to the Cereals and Other Produce Regulatory Authority (COPRA), the country exported 52,000 tonnes of avocado in the 2025/2026 season, beating its 2030 target of 40,000 tonnes four years early and earning US$97.2 million. National production rose to 203,473 tonnes, and the government plans to distribute a further 500,000 seedlings in 2026/2027. An industry growing this fast, and moving this much planting material, has a great deal to lose from a new pest.
What is the avocado seed weevil?
Heilipus lauri is a snout beetle (family Curculionidae) that feeds and breeds almost exclusively on avocado. The adult uses its long, beak-like snout to drill into young fruit. According to research by the University of California, Riverside, the female lays her eggs in a small chamber she chews beneath the skin (on average about two eggs per hole, sometimes more) and may plug the hole with chewed fruit skin.
When the eggs hatch, the larvae (grubs) tunnel through the flesh to the seed, burrow in and feed, causing extensive damage inside the fruit. They pass through four larval stages, then pupate inside the ruined seed. The new adult cuts a round exit hole and emerges to start the cycle again. Under laboratory conditions of about 21.6°C, development from egg to adult takes roughly 76 days, and adults can live for months.
Adults also feed on young leaves, green stems and the skin of both young and mature fruit.
Why it is so damaging
The danger of this weevil is that most of its damage is hidden. From the outside, an infested fruit may show only a small hole and some scarring; inside, the seed is being eaten. Seed feeding makes fruit unmarketable, and heavy infestations can cause fruit to drop early.
In its native range the losses can be severe. In poorly managed Hass orchards in Mexico, 30–38 per cent of fruit has been found damaged by the weevil, and in one survey of three poorly managed orchards in the State of México, about 63 per cent of hanging fruit showed damage. Because the grubs live inside the fruit, insecticide sprays struggle to reach them.
Where it is found, and why Tanzania should care
Heilipus lauri is native to Mexico and is recorded only in the Americas. Mexican plant health authorities, citing the European and Mediterranean Plant Protection Organization (EPPO), list it in Mexico, Guatemala, Costa Rica, Nicaragua and Colombia; Colombian surveillance documents also cite reports from other Central and South American countries. In Colombia it is an invasive pest, believed to have arrived from Mexico in avocado seeds used to raise rootstocks.
It has not been recorded in Tanzania, East Africa or anywhere in Africa. That is the good news. The concern is that it could arrive.
The weevil has already been intercepted in the United States in avocado fruit exported from Mexico and Colombia, and the US Department of Agriculture lists Heilipus weevils as avocado pests of high concern. California has run a proactive programme against it since February 2020, before any incursion, precisely because prevention is far cheaper than eradication.
For Tanzania, the main pathways would be the same: infested fruit, and above all avocado seeds or planting material brought in from the weevil’s native range. With a seedling programme counted in hundreds of thousands, unchecked imported seed is a real risk.
Damaged fruit is not always the weevil
Farmers who find holes or rot in their avocados should not assume they have found Heilipus lauri. Tanzania already has two well-documented pests that damage avocado fruit:
- Oriental fruit fly (Bactrocera dorsalis): an invasive fly that lays eggs in ripening fruit; its maggots speed up rotting. Research by icipe and partners on Mount Kilimanjaro and in Kenya’s Taita Hills found it makes up about 90 per cent of pest insects trapped in avocado farms in the two countries. Its spread cost Kenya and Tanzania the South African avocado market in 2007.
- False codling moth (Thaumatotibia leucotreta): a native African moth whose caterpillars bore into fruit and which is treated as a quarantine pest by major importing markets.
Both cause fruit damage and export rejections, and both are managed with tools that are already available: orchard sanitation, traps and lures, and good harvesting practice. Only a trained plant health officer, examining the insect itself, can confirm which pest is responsible.
What growers, nurseries and traders should do
- Never plant avocado seed of unknown origin. Buy seedlings and rootstock seed only from registered nurseries and known sources.
- Do not bring avocado fruit, seed or budwood into the country without a permit. Under the Plant Health Act No. 4 of 2020 and the Plant Health Regulations, 2023, importing plants and plant products requires a permit from the Tanzania Plant Health and Pesticides Authority (TPHPA), the national plant protection organisation.
- Inspect fruit regularly. Look for small drilled holes, scarring on the skin, early fruit drop, and seeds that are hollowed out or tunnelled when you cut fruit open.
- Collect and destroy fallen and damaged fruit. This also cuts fruit fly and false codling moth numbers.
- Report anything unusual. If you find a beetle with a long snout in or on avocado fruit, or seeds eaten from the inside, keep a sample in a sealed container and report it to your district agricultural extension officer or to TPHPA. Early detection is what keeps a quarantine pest out.
Prevention is the only affordable option
Tanzania has reached its avocado export goals years ahead of schedule. Keeping those markets depends on keeping pests like Heilipus lauri out. Once a hidden, seed-boring pest is established, it is hard to control and can close export doors.
As Mr Kirenga put it: “Tuwe makini tulinde mazao yetu,” meaning “let us be vigilant and protect our crops.”
Kwa ufupi (Kiswahili)
Fukusi wa parachichi (Heilipus lauri) ni fukusi mkubwa wa mbegu ya parachichi. Ni mdudu mwenye mdomo mrefu unaotoboa matunda ya parachichi ili kutaga mayai. Mabuu yake huingia ndani ya mbegu, hula na kuharibu tunda kutoka ndani, kisha mdudu mzima hutoka kwa kutoboa shimo dogo.
Ni mdudu hatari kwa kilimo cha parachichi kwa sababu uharibifu mara nyingi hufichika ndani ya tunda hadi wakati wa mavuno. Hii inaweza kusababisha matunda kudondoka mapema, kukosa soko na hasara kubwa ya mavuno.
Kwa Tanzania na Afrika Mashariki, fukusi huyu bado hajathibitika kuwepo, lakini ni tishio la karantini. Hatari kubwa ni kuingiza matunda au mbegu za parachichi zilizoambukizwa kutoka Amerika ya Kati na Kusini. Ni muhimu kukagua mazao yanayoingizwa nchini, kutotumia mbegu zisizojulikana asili yake, na kutoa taarifa kwa Afisa Ugani au TPHPA ukiona dalili zisizo za kawaida. Tuwe makini sana.
Sources
- University of California, Riverside: The Large Avocado Seed Weevil, Heilipus lauri: https://biocontrol.ucr.edu/large-avocado-seed-weevil
- UC Agriculture and Natural Resources: Proactive Management of the Avocado Seed Weevil: https://ucanr.edu/node/106104
- SENASICA (Mexico): Ficha técnica, Heilipus lauri: https://www.gob.mx/cms/uploads/attachment/file/155685/Ficha_T_cnica_Helipus_lauri_EPF_2016_1_.pdf
- SENASICA (Mexico): Regulated avocado pests: https://www.gob.mx/cms/uploads/attachment/file/758109/Regulated_Avocado.pdf
- Castañeda-Vildózola et al.: Oviposition biology of H. lauri: https://core.ac.uk/works/162395668
- Odanga et al. (2018), Insects: B. dorsalis and T. leucotreta in avocado, Taita Hills and Mount Kilimanjaro: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6023484/
- Avocado pest densities in Kenya and Tanzania (90% B. dorsalis): https://core.ac.uk/download/528258368.pdf
- Daily News: Tanzania avocado exports surpass 2030 target: https://dailynews.co.tz/?p=167460
- TanzaniaInvest: Avocado exports hit 52,000 tonnes and US$97.2 million: https://www.tanzaniainvest.com/?p=35270
- Plant Health Regulations, 2023 (GN 284 of 2023): https://leap.unep.org/en/countries/tz/national-legislation/plant-health-regulations-2023-gn-284-2023
- Plant Health Act No. 4 of 2020: https://assets.ippc.int/static/media/files/reportingobligation/2021/05/07/THE_PLANT_HEALTH_ACT_2020.pdf
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