pests and diseases
The tomato plant in the centre is most likely suffering from Fusarium wilt. I say probably as there are a number of soil bourn fungal diseases that show similar symtoms.
It is spread short distances by water splash and on garden tools, and long distances by infected transplants and seeds and in contaminated soil brought into your garden. While it can survive in a range of conditions in does best in warm moist soils.
For more details see the Fusarium Wilt entry in Wikipedia.
treatmentOnce in the soil Fusarium Wilt is difficult to eradicate. The best defence is to try and not introduce it to your vegetable garden in the first place. Do not transplant any plant that looks like it has the disease and avoid bringing in soils from other gardens. If it is introduced to your garden then below are steps you can take to control it.
- If possible do not plant vegetables susceptible to
Fusarium Wilt for at least three years.
- If planning vegetables that are susceptible in a bed
known to be contaminated with it then keep the watering to a
minimum, the dryer the soil the less likely that the pathogen
- Avoid using wicking beds as they create the warm moist
conditions that pathogen thrives in.
- If growing plants that are susceptible to Fusarium Wilt then choose varieties that have some resistance to it.
Note that there is a number of soil bourn fungal diseases that affect vegetables and they generally show similar symptoms to Fusarium Wilt. They are however usually treated in a similar fashion.