Formentera’s familiar prickly pear cacti are facing a growing threat from an aggressive cochineal insect that has spread across the island after previously causing extensive damage in Ibiza.

The pest, Dactylopius opuntiae, is attacking Opuntia cacti and leaving plants covered in distinctive white, waxy colonies. In affected areas, increasingly few healthy specimens are being found.

Locally known as figuera de pic, the prickly pear has become closely associated with the traditional rural landscape of the Pityusic Islands.

The Pest Is Spreading Across Formentera

The presence of Dactylopius opuntiae is becoming increasingly visible in Formentera.

Residents have reported the spread of the insect in recent years, while recent observations indicate that many prickly pear plants in areas including Sant Ferran are now affected.

The insects settle on the cactus pads, where they feed on the plant's sap.

Large colonies produce a characteristic white coating that can make heavily infested plants appear almost covered in cotton.

A Particularly Aggressive Species

Dactylopius opuntiae is native to the Americas and is an obligate parasite of plants belonging to the Opuntia genus.

It should not be confused with Dactylopius coccus, the cochineal traditionally associated with the production of carmine dye.

The two species are different, and Dactylopius opuntiae is considered considerably more aggressive towards its host plants.

The Canary Islands Government notes that the species has even been used in the Iberian Peninsula as a biological control agent against Opuntia because of its impact on the cactus.

How the Cactus Is Damaged

The insects feed directly on the cactus, weakening the plant as infestations become established.

The affected pads can develop chlorosis and necrosis, reducing their ability to photosynthesise.

With severe infestations, the plant can become increasingly weakened and may eventually die.

The insects are particularly difficult to reach because their colonies are protected by a waxy white secretion.

Wind Can Help Spread the Pest

One of the reasons the infestation can move rapidly is the mobility of the insect's early stages.

Nymphs can be dispersed by wind and establish new colonies on nearby cactus plants.

Once established, populations can grow across multiple pads, making heavily affected plants increasingly difficult to maintain.

This creates a particular challenge in areas where prickly pear plants grow close together in fields, along paths or around rural properties.

Ibiza Has Already Seen Severe Damage

The problem is not new to the Pityusic Islands.

Ibiza has been dealing with the spread of the pest for several years, with residents documenting the deterioration of prickly pear plants across different parts of the island.

The arrival of the pest in Formentera has therefore raised concern that the southern island could experience similar damage.

Formentera's environment officials have acknowledged the increasing presence of the insect and the difficulty of dealing with it.

A Familiar Part of Rural Ibiza and Formentera

Although prickly pear cacti originated in the Americas, they have been part of the rural landscape of Ibiza and Formentera for generations.

The plants have traditionally been found around houses, paths, fields and old livestock enclosures.

Their fruit, known locally as figues de pic, has traditionally been consumed, while the pads have also been used as feed for goats and sheep.

The cactus has therefore become part of the visual and agricultural heritage of the islands despite its non-native origins.

The Legal Complication

The situation is made more complicated by the legal status of several Opuntia species in Spain.

Spain's Ministry for the Ecological Transition includes species such as Opuntia maxima in the Spanish Catalogue of Invasive Alien Species. The official documentation records the species as widely naturalised in the Balearic Islands.

That classification means public policy is directed towards preventing the spread of listed invasive plants rather than promoting their reproduction or expansion.

This creates a particular difficulty in the case of Formentera's traditional prickly pear plants: the landscape value of the cactus does not change its status under Spain's invasive-species framework.

No Specific Public Eradication Programme for the Cactus

According to Formentera's Environment Department, there is currently no specific public programme aimed at treating the island's prickly pear population against the cochineal.

Officials have described the situation as serious but difficult to address.

The challenge is partly linked to the status of the host plant itself and the absence of a straightforward large-scale treatment capable of protecting the existing population.

Individual owners therefore have a different role from public administrations when it comes to trying to keep affected plants alive.

Treatments Can Be Attempted on Private Plants

Formentera's Environment Department recommends that individual owners can try treatments such as potassium soap or neem oil on affected cactus pads.

Because the insects are protected by their waxy coating, treatments need to be repeated and applied carefully.

Other measures used in areas affected by the pest include removing heavily infested pads and washing colonies away with pressurised water.

Any treatment should be used only in accordance with its authorised purpose and the manufacturer's instructions.

Care Is Needed With Edible Fruit

Extra caution is needed when prickly pears are producing fruit for human consumption or when cactus pads are used as livestock feed.

Owners should verify that any treatment product is authorised for the intended use and follow all application instructions.

Plant material removed from heavily infested cacti should also be handled carefully rather than simply being abandoned on the ground, as this could contribute to the spread of the pest.

The Canary Islands Offer a Warning

The experience of the Canary Islands shows how severe the problem can become.

Dactylopius opuntiae has been present there for years, where authorities have documented its impact on Opuntia plants.

The Canary Islands Government describes the insect as particularly aggressive and says serious infestations can cause major damage to prickly pear plants.

The experience provides a possible indication of what could happen in Formentera if the infestation continues to expand.

More Than a Change to the Landscape

Formentera's prickly pears are more than ornamental plants.

They are part of the agricultural and visual history of the island and are closely associated with traditional rural properties.

Their decline would therefore be noticeable not only in ecological terms but also in the character of the countryside.

At the same time, the island has to manage a plant that Spain officially treats as an invasive alien species in the case of listed Opuntia species.

What Happens Next?

For now, the cochineal continues to spread across Formentera, while individual landowners are left to manage affected plants where appropriate.

There is no confirmed island-wide programme to preserve the existing prickly pear population from the pest.

The scale of the problem will become clearer as further observations are made and more plants are affected.

Formentera's authorities and residents now face the difficult question of how to deal with a pest threatening a familiar part of the island's rural landscape while the cactus itself is subject to Spain's invasive-species regulations.

A Familiar Cactus Under Pressure

The white patches appearing across Formentera's prickly pear cacti are the visible sign of a much larger change.

Dactylopius opuntiae has already caused serious damage in Ibiza and is now becoming increasingly widespread on Formentera.

For an island where figuera de pic has been part of rural life for generations, the continuing spread of the insect could gradually change the appearance of the countryside.

For now, monitoring, careful treatment of individual plants and responsible handling of affected material remain among the practical measures available while the situation develops.