Characteristics
The use of F4 is recommended mostly in spring time, during the first growth stages, when the plant normally suffers from zinc and manganese deficiencies caused by cold and asphyxial soils and by the impaired absorption capacity of the root system.
As these microelements play a crucial role in the cell mitosis, such a deficiency in the early stages of growth will unmistakably give rise to a limited leaf development and an inadequate capacity of the plant to prepare its reproduction organs.

Pome fruits (apple and pear trees)
In pome fruits, the event leads to the undersized development of the first few leaflets which appear elongated. They tend to form weak rosettes unable of nourishing neither the flowers nor the small fruits.Treatment method : it is recommended to carry out 2 to 3 treatments with F4 in doses of 300-400 ml/hl starting at the appearance of stipules up to the flowering period; if need be it may be mixed with F1. In case of applications with reduced water volume, the dose of 1 lt/hl should not be exceeded. In case of serious deficiencies it is recommended to treat the plants in the summer-autumn months in order to better prepare the plants for the following spring.

Stone fruits (Peach, Apricot, Prune trees)
In case of noticeable deficiencies, treatments with F4 start about 3 weeks after flowering, at a rate of 3 to 4 applications at the dose of 300 ml/hl, up to a maximum of 1 litre for low volume treatments. In case of average deficiencies, it is recommended to alternate treatments with F4 and F2 which will deliver an optimal vegetative growth, a reduction of gummosis, well developed and prime quality fruit.

Citruses
Citruses are mostly sensitive to Zn and Mn deficiencies and respond to applications with F4 especially during growth and foliar system regeneration periods.
F4 is applied at the dose of 300 m/hl with about a two-week interval between applications and for at least 3 to 4 treatments.

Commercial crops
Among commercial crops, CORN is one of the most important and early sowing varieties are particularly sensitive to Zinc and Manganese deficiencies. Very good results can be obtained using F4 in combination with post-emergence weed-killers, at the dose of 1 lt/ha of mixture.
As F4 formulation is exceptionally rich in organic-hygroscopic matter and in softening substances, it stimulates the growth of soft, resilient and greener leaves. The fruits are firm and well coloured.