The disease cycle for all cucurbit Fusarium wilts is similar. Initial infection of seedlings usually occurs from chlamydospores that have overwintered in the soil. Chlamydospores germinate and produce infection hyphae that penetrate the root cortex, often where the lateral roots emerge. Infection may be enhanced by wounds or damage to the roots. The fungus colonizes the root cortex and soon invades the xylem tissue, where it produces more mycelia and microconidia. Microconidia may be carried in the transpiration stream up the xylem (Figure 8) where they may become lodged against the vessel wall or perforation plate. Subsequent germination results in hyphae that penetrate and emerge on the other side where they repeat the process of mycelial growth and sporulation. Consequently, the fungus becomes systemic and often can be isolated from tissue well away from the roots. Once infection has occurred, FON is limited to the xylem and generally emerges only after death of the plant.
 Figure 8 |
In response to the advance of the fungus within the xylem, the host plant typically produces tyloses, in an attempt to restrict pathogen movement. Tyloses are invaginations of the xylem parenchyma cells that grow into the vessels and impede water flow (Figures 9-13), as compared to vessels in healthy plants with no tyloses (Figure 10). If the tyloses form quickly enough and sufficiently to completely plug the xylem vessel, before the fungus has proceeded up the plant, they may prevent systemic colonization of the xylem - the result being a resistant plant. In susceptible plants, however, tyloses form more slowly and do not completely block the vessel (Figures 9 & 11), ultimately allowing the fungus to pass through. As the fungus continues to colonize the xylem, more tyloses are formed, eventually restricting water flow and causing the vine to wilt. The formation of tyloses in some vessels and not in others partially explains the ‘one-sided’ wilt (Figure 1) often seen in watermelon and muskmelon. In addition, the pathogen causes a general breakdown of the xylem parenchyma cells resulting in various types of gums that add to the blockage. The extent to which fungal toxins are involved in pathogenesis is not known. Further colonization of the tissue results in necrosis and cellular gums that hastens wilt and death of the plant and produces the characteristic brown discoloration of the vascular tissue (Figures 3 & 4). Because the fungus is systemic in the xylem, it can be readily isolated from diseased plants by surface-disinfesting cross sections of the stem or root and plating them onto a growth medium. Mycelium of F. oxysporum will emerge directly from within the xylem within 24 - 48 hours (Figures 14 and 15).
 Figure 9 |
 Figure 10 |
 Figure 11 |
 Figure 12 |
 Figure 13 |
 Figure 14 |
 Figure 15 |
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The vascular wilt fusaria spend most of their time within the plant. In the very late stages of disease or upon plant death, the fungus begins to grow profusely along the outside of the decayed stem, producing thick mats of white mycelia (Figure 16) and abundant macroconidia. Macroconidia become incorporated into the soil and, along with the mycelium, convert into chlamydospores, which can remain dormant until next season. Chlamydospores formed within the mycelium may survive in a dormant state in the soil for 15 to 20 years.
 Figure 16 |
ORGANIC REMEDIES
FOR
FUSARIUM WILT
ON PLANTS
It is difficult to fight fusarium wilt.
But it is not impossible.
To prevent plants from powdery mildew, controlling and getting rid fusarium wilt. You can prepare own special organic liquid mixture for fusarium wilt yourself, both economically and so effective.
To prepare this special organic liquid mixture, You need some ingredients that you can find your country easily, formulation and production process. You need no help and no technıcal support to make this mixture. simple mixing is sufficient.
Below textbook has a formulation and manufacturing process of special organic liquid mixture and methods of application to treat fusarium wilt . You can produce special organic liquid mixture for fusarium wilt easily and apply to plants safety.
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