Yellowing disease refers to the phenomenon of yellowing or yellow-greening of some or all of the leaves of a plant as they regress.

There are two major types ofyellowing disease, namely pathological yellowing disease and physiological yellowing disease.

Pathological yellowing disease symptoms are pathogenic microorganisms infecting the tree's root system, leaves or other tissues and cause yellowing of leaves, the onset of which has the characteristics of proliferation and spread, such as yellowing disease of purple leaf plum.

Physiological yellowing symptoms is the tree growth process by the soil environment or atmospheric environmental factors of stress, the normal physiological function of the tree is hindered by the performance of leaf greening and yellowing as the main characteristics of the class of symptoms of the general term. The main cause of physiological yellowing of trees is deficiency, which is more common is iron deficiency, sulfur deficiency, nitrogen deficiency, magnesium deficiency, zinc deficiency, manganese deficiency and copper deficiency resulting in physiological yellowing. The predisposing factors are soil infertility, fertilizer damage, drought, flooding, and atmospheric toxicity. For example, the following situation.

For the control of physiological yellowing, the first step is to find out the cause of the disease and then treat the symptoms. If it is caused by flooding, drainage should be strengthened to prevent water from accumulating after rain, and daily maintenance management should be strengthened. If the yellowing disease is caused by drought, watering should be strengthened, especially in dry weather with lack of rain, for some tree species with weak drought tolerance. If the yellowing disease caused by soil infertility, it should be timely according to the soil lack of fertilizer, the right time, the right amount, targeted fertilization. Fertilizer should pay attention to the application ratio of chemical fertilizer and farmyard manure, not a single application of chemical fertilizer. If the yellowing disease caused by fertilizer damage, the fertilizer should be removed in a timely manner; if the application of chemical fertilizers, it should be flushed with water and take measures to change the soil; if the yellowing disease caused by atmospheric toxicity, one should reduce or control the source of toxic gases, control of air pollution, for the moment can not change the environment, should consider replacing the tree species, the selection of resistant species.

As mentioned earlier, trees lacking iron, magnesium, manganese, nitrogen, potassium, zinc, copper and other elements will appear leaf yellowing, but each and different performance. If the yellowing disease caused by deficiency, first of all, according to the plant deficiency performance to determine the lack of which elements, it is not easy to judge by observation, it should be planted in the soil sampling and testing, and then symptomatic treatment. Yellowing disease caused by iron deficiency is the most common physiological yellowing disease, and its symptoms are very obvious: the earliest manifestation of symptoms is the young leaves of the branches, and then to the old leaves. At the beginning of the disease, the leaf veins are green and the tissue between the veins is yellowed. When there is a severe iron deficiency, the old leaves in the middle and lower parts of the branches, the leaf margins or leaf tips appear scorched or necrotic, and finally the leaves fall off. Adopting to improve the soil environment in the root zone of the plant, promote the dissolution of iron and improve the absorption of iron by the plant is the main idea to treat the yellowing disease of trees.

This product is a nutritional fertilizer specially developed for physiological yellowing disease. Flushing or spraying this product can improve the root or leaf micro-ecological environment, micro-acid environment conducive to the absorption and utilization of trace elements.

Sugar alcohol completely chelated trace elements, nutrients can be quickly transported in the crop phloem, by the demand for parts of the direct absorption and utilization, which is the conventional trace element fertilizer is incomparable. This product is a comprehensive complementary element, a spray can make up for the lack of various nutrients in physiological yellowing disease, with the advantages of time-saving, trouble-saving, accurate, efficient and so on.

The following is the specific test situation of spraying three times of physiological yellowing fly prevention fertilizer for hanging orchids, and the effect is obvious in comparison.

                                                                                                      The left side is not used                                                        the right side is foliar spraying 3 times.