• Vascular wilt shown on the sunflower is a common symptom of an Fusarium oxysporum infection.wilting sunflower image by Deborah Benbrook from Fotolia.com
  
  Fusarium oxysporum is a fungal pathogen that affects a variety of food crops and ornamental plants. According to the University of Hawaii, various forms of Fusarium oxysporum cause vascular wilt, root-rot, yellowing of leaves and damping-off. Vascular wilt is the most common and serious of the disorders that the pathogen causes. Plant essential oils, extracted from a variety of different plants, are an effective organic method of controlling the fungus.
  
  

Cymbopogon Citratus

• Essential oils are collected from a variety of various plants, each having their own levels of toxicity against the fungal pathogen Fusarium oxysporum. According to a study done by the American Society for Microbiology, the essential oils extracted from Cymbopogon citratus or lemongrass showed 100% toxicity against fungal growth. The essential oils from lemongrass at 1,000 ppm (parts per million) inhibited fungal growth and destroyed 100% of fungal growth activity during the months of May to November, according to the American Society for Microbiology. However, the potency of the oil decreased during the months of February to April, which means it has varying levels of toxicity during different months.
  
  

Zingiber Officinale

• Oils extracted from Zingiber officinale, also known as ginger, are a common effective control for Fusarium oxysporum. According to a study done by the African Journal of Biotechnology, essential oils extracted from ginger produced 32.7 to 69.2% effectiveness against the fungal growth. The results show a strong correlation between the use of essential oil of ginger use and the inhibited growth of Fusarium oxysporum. The essential oil extracted from ginger is being used as an organic fungicide against vascular wilt, which accounts for a large portion of crop damage.
  
  

Cymbopogon Proximus

• Essential oils extracted from Cymbopogon proximus, or halfa barr, is another effective method of control for Fusarium oxysporum. Cymbopogon proximus is native to Egypt and from the same lemongrass family as Cymbopogon citratus. A study done by the African Journal of Biotechnology showed that the oils from halfa barr resulted in 42.3 to 75% effectiveness against the growth of the fungus. Because the oils from halfa barr are among the most effective natural methods of control against Fusarium oxysporum, and the fungus Alternaria alternata, the oils are being used as an effective alternative to fungicides. In the study, the effectiveness of halfa barr was greatly influenced by the amount used, which was .13 to .30 g/50 ml. The greater concentration resulted in higher toxicities, which inhibited the growth of the fungal pathogen by nearly 75%.