Fungicides translocation

Systemic fungicide, translocated acropetally within the plant... 

Systemic foliar fungicide, translocated acropetaly in the xylem... 

CGA 245704 (acibenzolar Figure 4.39) may operate in a similar manner to natural defence activators. It does not possess fungicidal activity per se but induces resistance to a wide range of pathogens. The product is readily translocated in the phloem and xylem but is subject to rapid metabolism. 

Staub, T., Dahmen, H. and Schwinn, F.J. 1978. Biological characterization of uptake and translocation of fungicidal acylalanines in grape and tomato plants. Z. Pflanzenkr. Pflan-zenschutz 85, 162-168. 

Professor Filhr discussed penetration, translocation and distribution of fungicides in plants. These aspects of fungicide performance are often critical in determining the success of a systemic fungicide in a particular type of application. The ability to penetrate into plant tissue and move while retaining activity therein is the primary basis for the superiority of the newer systemic fungicides over the older surface protectants. Internal therapeu-tants may also influence the host physiology and as a consequence, be assisted by the natural defense system of the host. 

Carris, L.M. (1983) Movement of the systemic fungicide metalaxyl in soils and its translocation in plants. M.S. Thesis, Washington State University, Pullman, Washington. 

Systemic fungicide absorbed by roots, stems, leaves with translocation acropetally to all parts of the plant including subsequent growth... 

Systemic fungicide, absorbed through roots and green tissues, with translocation acropetally. Acts by inhibiting development of the germ tubes, the formation of appressoria and the growth of mycelia... 

Systemic fungicide, which readily penetrates into the leaf tissue followed by acropetal translocation to the leaf tip... 

Systemic fungicide absorbed through roots and leaves with ready translocation in young growing tissues but less ready translocation in older, woody tissues... 

Systemic fungicide, absorbed by leaves and roots with translocation acropetally... 

Many commercial fungicides currently in use belong to the class known as protectant or surface fungicides. These are usually apphed to plant foliage as dusts or sprays. Such materials do not appreciably penetrate the plant surface of cuticle and are not translocated within the plant, whereas the more recent systemic fungicides are absorbed by the plant via the roots, leaves, or seeds and are translocated within the plant. 

Most of the early systemic fungicides (benomyl) showed translocation through the xylem. However, pyrimidine systemic fungicides e.g., ethirimol and dimethirimol, appear to move through the phloem. 

As with almost all systemic fungicides, after foliar or soil application, absorption and translocation via the xylem follows. The mechanisms of action of pyrimidines are not very clear, however, information suggests that spore germination and mycelial growth are inhibited. In addition, studies with ethirimol suggest that it inhibits RNA synthesis as well as adenosine metabolism by blocking adenosine deaminase. 

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