Euphyllura olivina, commonly known as the “olive milkweed”, is a homopterous insect belonging to the Psyllid family. Historically, its presence in olive groves has been frequent, but it has not represented a significant threat that would justify phytosanitary control measures.

The Ministry of Agriculture’s Pest Management Guidelines have traditionally considered Euphyllura olivina as a secondary pest, since its effects on olive production were marginal. Consequently, there were no chemical treatments authorized for this use on the crop.

Increased damages as of 2017

Since 2017, a drastic increase in the damage caused by this species has been observed in some specific areas of southern Spain, with losses in the olive harvest ranging from 20% in the least severe cases to up to 80% in the most extreme cases. These figures have translated into losses of approximately 6 million kilos of olives, equivalent to 1.2 million kilos of olive oil, affecting more than 400 hectares of olive groves in the south of the province of Cordoba.

Biological cycle of Euphyllura olivina

The olive milkweed mainly affects the flowering of the tree, causing the flowers to suffocate and desiccate. In addition, the nymphs of Euphyllura olivina feed on the sap of the olive tree, weakening the plant and reducing its productive capacity.

The life cycle of this psyllid is closely linked to the vegetative activity of the olive tree:

• First generation: It starts at the end of winter and beginning of spring, affecting new sprouts.
• Second generation: Coincides with the development of inflorescences and buds, the period in which the most critical damage is generated. The nymphs secrete a protective cottony substance while feeding on the sap, which weakens the plant and significantly reduces the fertility of the olive tree by causing the premature fall of flower buds and a decrease in fruit set.

Environmental factors and natural regulation

The development of this pest is strongly influenced by climatic conditions. Dry years favor its proliferation, while heavy rains can considerably reduce the nymph population.

Euphyllura olivina is naturally controlled by several natural enemies, including Chrysoperla carnea and Anthocoris nemoralis as predators and Alloxysta eleaphila and Phyllaephagus euphyllura as parasitoids. Plant Health has suggested that the proliferation of this pest could be related to the population decrease of its predators and parasites due to the intensive use of pyrethroid insecticides.

Control strategies and use of insecticides

The International Olive Council has established a phytosanitary treatment threshold when at least 2 nymphs per inflorescence or more than 60% of the inflorescences covered by cottony secretion are detected. However, this treatment coincides with a critical phase for auxiliary organisms, so it is recommended to avoid the use of pyrethroids and other insecticides that do not respect auxiliary fauna.

Faced with the risk of a new infestation, the Ministry of Agriculture has exceptionally authorized the use of phytosanitary products based on pyrethrins 4.65%, such as pyrethrum extract, between February 15 and June 14, 2025. However, the effectiveness of this exceptional measure is not entirely clear and we explain why.

The main obstacle in the phytosanitary control of Euphyllura olivina lies in the protective capacity of its cottony mass, composed of waxy filaments that prevent the penetration of insecticides. Therefore, the key to control lies in breaking down this barrier to facilitate the action of phytosanitary products.

To break up this cottony mass, the application of oily solutions is recommended, such as GLOBBER, whose composition allows it to adhere strongly to the waxy filaments that make up the cotton created by the nymphs of Euphyllura olivina to protect themselves. This allows the dissolution of the cottony mass and facilitates the action of the insecticide on the psyllid, maximizing its effectiveness and ensuring a higher level of control.

Other success stories

In 2024, in order to develop integrated control strategies against pests that generate protective cottony secretions, such as the aforementioned Euphyllura olivina or Eriosoma lanigerum (woolly apple aphid), protocols based on the combination of authorized insecticides, such as deltamethrin or acetamiprid, with the biostimulant GLOBBER were implemented. The results showed an increase in insecticide efficacy between 15% and 20%, in addition to a significant visual impact, thanks to the almost total elimination of the cottony secretion on branches, shoots and inflorescences.

The proliferation of Euphyllura olivina in recent years has highlighted the need for more efficient and sustainable integrated control strategies. The indiscriminate application of pyrethroid insecticides has not only shown limited efficacy due to the insect’s protective cotton barrier, but has also negatively affected the natural enemies that regulate its population.

The use of biostimulants such as GLOBBER, in combination with authorized insecticides, has proven to be a viable solution by significantly improving the penetration and efficacy of phytosanitary treatments. The implementation of this approach could mark a turning point in the integrated management of olive milkweed, contributing to the sustainability of the crop and the protection of the biodiversity of the olive ecosystem.