Purging the Pine Tree Pest

Having spent the colder months gorging themselves on pine needles and relaxing in the web-like nest, fully grown processionary caterpillars begin their march down the tree trunk in February or March - earlier, if the winter is mild. Their aim is to bury themselves in soft ground, pupate, and manifest several months later as a processionary moth. But, during their search for a burrowing spot, the caterpillars form nose-to-tail processions that can extend to many metres. This is when they’re at their most menacing.

If threatened, the caterpillar’s defence mechanism is to eject some of its up-to-500,000 trichomes in the direction of an assailant. These hairs contain highly potent irritants that can cause eye irritation and troublesome rashes on humans and, should your pet sniff, lick or eat them, possible necrosis of the tongue, severe swelling and suffocation – get to the vet immediately.

The good news is that this cycle happens only once each year. The bad news is that the marching phase can last a number of weeks - a long time to suffer a state of anxious alert for your loved ones.

There are solutions. Hormone traps make boy caterpillars smell like girl caterpillars, they’re so confused that fewer babies are produced. But, results are inconsistent and it can affect the mating behaviour of other harmless insects. Nests can be burnt and destroyed, but this has to be done carefully by a professional. Also, pines are a protected species, so removing the tree entirely is rarely an option. The safest, most efficient way is endotherapy. One single treatment between September and December (AKA now) is enough to control this pest for an entire year. Doctor Pino is the Island’s expert.

The Sarnovichs moved to Mallorca from Argentina four decades ago. A young Guillermo launched a landscaping/gardening business, with father Carlos joining later to lend a hand. Around 17 years ago, Carlos and Guillermo began researching alternative approaches to the usual spraying technique (polluting, expensive, and not particularly efficient) and discovered that other regions were successfully treating processionary caterpillars – including the oak processionary caterpillar you find in the UK – with a drug injection method, or endotherapy. The procedure didn’t contaminate, was very reliable and could save dogs’ lives from this decidedly dangerous caterpillar. As a family of dog lovers, they added the treatment to their list of services. When Carlos’ health began to falter, elder son Federico took over the endotherapy side of things, rebranding as Doctor Pino after his father sadly passed away in 2019.

Federico picks up the story: “Processionary caterpillars may look fluffy and unassuming, but their presence is far from harmless. Aside from the direct health threat they pose to humans and pets, their pine-needle diet causes substantial damage to Mallorca’s lush forests, with the destruction having far-reaching consequences, including soil erosion, diminished biodiversity, and a less hospitable environment for our Island’s rich wildlife. It’s an issue that must be urgently and proactively addressed, but many traditional methods come with their fair share of drawbacks.

“Chemical pesticides have obvious harmful environmental and health implications. Toxins can contaminate our soil and water, attack non-target species, and contribute to the development of pesticide-resistant caterpillar populations. Physically removing nests from trees is labour-intensive and potentially hazardous due to the caterpillars’ toxic hairs. It also falls short as a long-term solution as it doesn’t address the root causes of caterpillar infestations. Pheromone traps are commonly spotted throughout our forests and lure male processionary moths, disrupting their mating behaviour. While less pernicious than chemical pesticides, outcomes are patchy and may have knock-on effects for innocent insects. As for shooting the nests – yes, it happens – it doesn’t take much imagination to see the downside of flying caterpillars and bullets.

“Endotherapy is Doctor Pino’s procedure of choice. It involves injecting insecticide into the trunks of pine trees - the caterpillars’ primary habitat - and offers distinct advantages over traditional eradication methods. First, the precision of the application. Trunk injection delivers a small quantity of insecticide directly to the caterpillars’ habitat, minimising harm to non-target species and reducing environmental contamination. Chemical sprays, by contrast, can drift to unintended locations. Second, this same precision means beneficial insects such as bees and butterflies come to no harm, fostering a healthier ecosystem. Third, there is minimal risk to human health, with neither airborne toxins nor direct contact with the caterpillars. Fourth and finally, the effects are long lasting. The insecticide remains active for several months within the tree, providing enduring protection against caterpillar infestations.”

The ideal time to carry out endotherapy is from mid-September until the first week of December when the caterpillars are weak and have not yet reached their stinging stage. The tree will uptake the injected liquid through its vascular system, transporting it to the leaves, where it will swiftly eliminate any munching caterpillars, preventing them from progressing to the dangerous stage. Doctor Pino inject by hand, and do not use compressed air machinery that can damage the structure of the tree. In fact, the holes ‘heal’ in a very short time.

Doctor Pino does not charge a fixed price per tree, but per injection, and the number required to be 100% effective depends on trunk diameter, height, and crown size. After a site visit, Federico and his team provide a no-obligation quotation. Doctor Pino guarantees that all living creatures in the vicinity of the treated pine tree will be free from processionary-caterpillar-related problems for a whole year. Peace of mind indeed.

Doctor Pino (www.doctorpino.es) is fully licenced to handle the necessary tools and products and is a member of both the Balearic (Associació Balear de l’Arbre (ABA)) and Spanish (Asociación Española de Arboricultura (AEA)) tree associations.