Periodico olivo 29 Maggio 2026

Subscribe to the Aipo YouTube channel to stay updated - Magazine No. 22 of May 29, 2026 - Phenological phase: from flowering to petal fall in early varieties. Weather data from recent days show maximum temperatures in the olive groves between 28 and 32°C, with average humidity of 60–70% and cool nights around 18–19°C. These conditions do not damage the pollen, do not burn the stigmas, and do not compromise fruit set: the flowering olive tree only begins to show stress above 33–34°C, especially if accompanied by warm winds and relative humidity below 30%. In some areas, however, local peaks have been recorded that reached or exceeded this threshold, resulting in a true heat stroke during full bloom. In such situations, high temperatures can reduce pollen vitality and slow its germination on the stigma, increasing the risk of irregular fruit set, particularly in plants already experiencing mild water stress or that flower in more exposed microclimates. It should also be remembered that spraying the canopy in the evening does not lower flower temperature: the water evaporates quickly, does not alter the internal temperature of the tissues, and does not create a stable microclimate. With evening humidity above 70%, as is the case these days, watering can hinder pollination, as pollen remains moist and heavy in the morning for longer, with reduced wind dispersal capacity. It is therefore essential to maintain adequate soil water levels and preserve the olive grove's microclimate stability, avoiding foliar treatments that could interfere with pollination. Plant protection Olive moth (Prays oleae): limited presence of adults in monitoring traps. Union stink bug (Palpita unionalis): Increased presence; if necessary, Bacillus thuringiensis var. kurstaki can be used; it's best to wait until after flowering. Olive cotton (Euphyllura olivina): Present in many olive groves, white oils are also effective against Union stink bug, if necessary immediately after fruit set. Olive thrips (Liothrips oleae): If necessary, natural pyrethrins, white oils, and copper-based products can be used to limit the spread of the parasite, possibly immediately after fruit set. Brown marmorated stink bug (Halyomorpha halys): Visual inspection of the olive grove has revealed an increase in individuals, especially on the edges. No intervention is currently necessary. Peppercorn scale (Saissetia oleae): Nymphs account for approximately 30% of hatches. Please refer to upcoming bulletins for further information on development dynamics and specific treatment recommendations. Olive fruit fly (Bactrocera oleae): Anyone intending to use traps for mass trapping in their olive groves should plan their purchase and placement. The optimal time is immediately after fruit set and the first growth. Notes on the use of Bacillus thuringiensis Bacillus thuringiensis is a spore-forming bacterium; its protein crystals are highly sensitive to climatic factors. The optimal temperature window for its use is between 20°C and 28°C. The insecticide only works if the Margaronia larvae, or other insects, actively ingest it. Below 15-16°C, the larvae's metabolism slows, they stop feeding, and the treatment fails. Above 30°C, there is a risk of premature protein degradation. The best time to apply it is late afternoon or at dusk, because the sun's ultraviolet (UV) rays destroy the protein crystals of Bacillus thuringiensis within a few hours. This bacterium has no systemic properties and is easily washed away, so if the forecast calls for rain within 24-48 hours, application should be postponed. The dose depends on the commercial formulation chosen (wettable powder or concentrated suspension), but the primary objective in olive trees is to ensure a high volume of water to thoroughly wet the young apical shoots, where the Margaronia larvae build their silken nests. Bacillus t. is lethal against first- and second-stage larvae, those just a few millimeters long, but has limited effectiveness against mature larvae, the third and fourth instars, which have already built a dense silken nest and are close to chrysidation. Visual monitoring of shoots at the end of flowering is essential to detect the very first leaf erosions. Since the tissues of young olive shoots can be tough or waxy, adding an organic tackifier/wetting agent (such as pine oil or soy lecithin) improves the distribution of the liquid film on the leaves and increases their resistance to leaching. Subscribe to the Aipo YouTube channel to stay updated -