Ultrasol and Speedfol B SP help control plant vigor in avocado orchards

Controlling vigor in intensive avocado orchards is a fundamental challenge to prevent early overcrowding and ensure high production levels. In these systems, the fruit is often consumed locally and also exported, mainly to the United States.

Vegetative Growth and Fruit Setting in Avocado Inflorescences

Unlike mango or lychee, setting in avocado inflorescences does not inhibit vegetative development of adjacent lateral shoots.
In fact, new growth emerges from the same inflorescences after flowering and initial fruit setting (indeterminate inflorescences).
This vigorous growth often competes with fruit development, causing excessive fruit drop. For this reason, growth regulators such as paclobutrazol and uniconazole are key to controlling vigor and improving fruit retention.

Pruning techniques to control vigor in avocado orchards

Each year, high pruning and selective lateral pruning are recommended during the post-harvest period. This prevents trees from crowding together in the row and prevents excessive expansion of the root systems.
Selective lateral pruning removes only the branches extending beyond the desired space, promoting controlled growth in dense rows, a common technique in high-density systems.
It is crucial that both sides of the rows receive direct sunlight for most of the day and that the spaces between rows remain open to facilitate ventilation and light.

Application of growth regulators in avocado trees: Paclobutrazol and Uniconazole

In high-density avocado orchards, vigor control should begin when the trees approach their final size within their row, which usually occurs 2 to 3 years after planting in layouts of 4–5 m between rows and 2–3 m between plants.
To promote flowering at this stage, doses of 30 to 50 ml of paclobutrazol per tree applied to the soil are recommended, as foliar applications may be less effective due to runoff from the leaves.

Use of Uniconazole with Ultrasol® K

Uniconazole applied during flowering together with Ultrasol® K, helps reduce fruit drop and improves fruit size in Hass avocados, a variety that commonly presents size issues due to the longevity of the ovule after fertilization.
For best results, spraying with uniconazole followed by two applications of Ultrasol® K at 2% (w/v) is recommended.

Foliar fertilization and alkaline soils in avocado crops

Soils with a pH above 7.5 limit the absorption of essential micronutrients such as Iron (Fe), Zinc (Zn), Manganese (Mn), Copper (Cu), and Boron (B).
In these cases, it is necessary to incorporate micronutrient chelates into the spray tank to improve foliar absorption:

• EDTA Zn: 300 g/100 L
• EDTA Mn: 250 g/100 L
• EDTA Cu: 100 g/100 L
• EDDHA Fe: 500 g/100 L
• Speedfol™ B SP: 300 g/100 L