Control
Control of the American Dagger Nematode presents problems because X. americanum is hard to completely remove. Nematicides generally remove up to 95% of the nematodes in soil, however the 5% that remain can reproduce asexually and the viruses that they carry can still infect the roots of young plants. Therefore, to eliminate the nematodes, nematicides should be used along with having a bare soil field for at least a 2 year period. This ensures that the X. americanum has no food source. At the end of this 2 year period the nematodes should be eradicated.
The spraying of nematicides also causes plants to release allelopathic chemicals. These chemicals then kill the nematodes by active suppression because they are toxic to the nematode. Crop rotation is another form of control for X. americanum. It has been shown that certain non-host plants may deny the nematode population an adequate food source for reproduction, and thus greatly reduce its population in the soil. This is termed passive suppression.
X. americanum can only travel via run-off and in damp soil, therefore if soils are kept dry enough the nematodes can be localized and quarantined.
Additionally, if soil is tilled frequently, X. americanum will likely not be in high enough of a population density to cause any noticeable symptoms in its hosts. There is also evidence of X. americanum resistance and "tolerance" seen in certain species of grapes that appeared to be better adapted to the parasite.
Read more about this topic: Xiphinema Americanum
Famous quotes containing the word control:
“America is neither free nor brave, but a land of tight, iron- clanking little wills, everybody trying to put it over everybody else, and a land of men absolutely devoid of the real courage of trust, trust in life’s sacred spontaneity. They can’t trust life until they can control it.”
—D.H. (David Herbert)
“Above and beyond paying attention to feelings before and after a separation, never threaten your child with leaving or loss of love in an effort to control her behavior. Children believe their parents’ assertions that “I will send you away,” “I won’t love you any more,” “I’ll go away,” and are terrified with good reason. Fear is a very poor way of disciplining a child, and it can cause severe lifelong anxiety.”
—Alicia F. Lieberman (20th century)
“Knowledge in the form of an informational commodity indispensable to productive power is already, and will continue to be, a major—perhaps the major—stake in the worldwide competition for power. It is conceivable that the nation-states will one day fight for control of information, just as they battled in the past for control over territory, and afterwards for control over access to and exploitation of raw materials and cheap labor.”
—Jean François Lyotard (b. 1924)