Avocado production has boomed worldwide in recent years, and Spain, including the Canary Islands, has been no exception. The number of avocado growers in the region has increased significantly as growers recognize the potential of this crop. However, several species of spider mites (Tetranychidae) pose a risk to this crop, with the genus Oligonychus being the most diverse and having the greatest economic impact. In particular, Oligonychus perseae (Tuttle, Baker and Abbatiello) has been reported as the one mainly responsible for the economic damage in major avocado-producing regions worldwide. In this paper, we aim to present an overview of the studies conducted and the measures implemented to mitigate the impact of O. perseae after its arrival in the Canary Islands. Our objective is to provide a detailed description of the current status of this pest (O. perseae), with special attention to its situation 17 years after its first appearance in avocado crops in the Canary Islands. In doing so, we aim to provide valuable insights and knowledge to understand and manage better the challenges posed by O. perseae in this region.

The Persea mite, Oligonychus perseae Tuttle, Baker & Abbatiello (Acari: Tetranychidae), is an economically important foliar pest of avocados in Spain. The effects of this mite on the foliar damage, production losses and economic impact were assessed in two avocado, cv. Hass, orchards located in the main growing areas of Spain (Northern Tenerife and Málaga) for 3 and 5 consecutive years, respectively. The economic injury level (EIL) for the optimization of the use of acaricides to control this mite was also established, considering three spraying strategies: (i) mite-free treatment (<50 mites per leaf), (ii) conventional treatment (50–150 mites per leaf), and (iii) control treatment (the absence of spraying). Persea mite populations were sampled fortnightly and foliar damage was estimated. At the end of each season, fruits were harvested, weighed and production losses were quantified. The cumulate mite-days (CMDs) had a significant effect on the percentage of leaf area damaged (PLAD) and yield reduction. High numbers of the Persea mite caused extensive damage to leaves, so a loss in tree yield was evident. However, for the middle population level, there was no evidence of yield losses. The quantitative EIL was estimated at a PLAD of 17%, equivalent to a CMDs of 178 mites per leaf, which is the amount of damage that should not be exceeded. In Northern Tenerife, with a mild climate, the Persea mite can reach significant populations that are maintained throughout the months. In avocado orchards in Málaga, the summer is hotter and drier, so the presence of the mite exists for a shorter duration in the seasons, with less damage to the leaves. In Tenerife, yield loss can be compensated by chemical treatments that permit pest control.

The effect of alkali stress on crop production has gained importance around the world. Avocado (Persea americana Mill.) is considered a salt-sensitive species, but the effect of alkaline water on avocados has not been sufficiently studied. Plant growth, leaf damage, and chemical analysis were evaluated in response to alkali salt (NaHCO₃) and neutral salt (NaCl) stresses on six clonally propagated avocado rootstocks. All plants exhibited exclusion mechanisms by the accumulation of Na⁺ and Cl⁻ in their root systems, Na⁺ was concentrated to a greater extent than Cl⁻. The accumulation of Na⁺ in the leaves was greater when applied as NaHCO₃ compared to the NaCl treatment. Although Cl⁻ toxicity is more commonly observed under usual field conditions, in our experiments when Na⁺ reached the leaves it caused nearly two times more leaf necrosis.

The Canary Islands are a Spanish archipelago, where the greatest water demand comes from agriculture. Being an outermost European region that receives a large number of tourists per year, the need for greater food sovereignty becomes more important. It is vital to undertake studies on the water footprint (WF) of the main crops, in order to identify the irrigation practices of local farmers and establish recommendations for water saving through improvement of these practices. The results of this study show that the average WF for bananas in the Canary Islands is 340.80 m³ t⁻¹ ± 34.07 and for avocadoes is 1741.94 m³ t⁻¹ ± 286.16. The WF models proposed can explain 92 and 86% of the total variance of the WF for banana and avocado crops, respectively. The WF of both crops can be reduced, and this work can be a starting point for improvement. Farmers will face a change in temperature and water availability due to climate change; useful water saving strategies for local farmers can now be made based on estimation of the WF with yield and net needs data.