Scientific name: Fusarium oxysporum
Causal organism: Fungus
Important Fusarium diseases
Banana wilt; Panama wilt (F. oxysporum f.sp. cubense)
Fusarium wilt of cotton (F. oxysporum f.sp. vasinfectum)
Fusarium wilt of sweet potato; Stem rot (F. oxysporum f.sp. batatas)
Fusarium wilt of tomato (F. oxysporum f.sp. lycopersici)
Fusarium yellows of common beans (F. oxysporum f.sp. phaseoli)
Tomato and other solanaceous crops, sweet potato, legumes, cucurbits and banana are the most susceptible plants but it will also infect other herbaceous plants
Affected plant stages
Seedling but mostly during reproductive stage
Affected plant parts
Banana wilt; Panama wilt
An infected plant is characterized by a strong yellowing of the leaves that remain erect for 1 - 2 weeks. Some of the leaves may then collapse at the leaf stalk and hang down at the pseudostem
. The leaves fall in order, from the oldest to the youngest, until they hang about the plant like a skirt, and dry up. The fungi grow in the vascular system causing the plant to wilt. A lengthwise cut on the pseudostem will show numerous brown and black lines running in all directions, and it emits a strong unfavorable smell. Infected suckers
growing out of diseased corms
produce plants that wilt and eventually die out. Leaf symptoms appear after the fungus has spread through the corm. In younger plants, the first signs of infestation are to be found on the unfurling leaf which turns yellow and dies off.
Fusarium wilt of cotton
Yellowing, wilting, defoliated plant, and plant death are the typical symptoms. If a stem is cut lengthwise near the base, its vascular tissues below the bark exhibit a brownish discoloration through the entire main stem.
Fusarium wilt of sweet potato; Stem rot
Yellowing and wilting of the lower and older leaves, and the vines turning tan to light-brown are the typical symptoms. The dying vines have pinkish fruiting bodies of the fungus. The tubers produced by an infected plant have discolored vascular tissues which may rot upon storage.
Fusarium wilt of tomato
Infestation often occurs on mature plants after flowering and at the beginning of fruit set. The initial symptom is the yellowing on the lower leaves and a slight wilting on the infected shoots. Yellowing begins to appear on one side of a leaf and then all leaflets become yellow on the other half of the leaf. As the disease progresses, one side of the plant wilts and this process spreads to the other side as the infection worsens. An infected plant often dies before maturing.
Fusarium yellows of common beans
Infestation often occurs on medium-aged or older plants. It begins as a yellowing and wilting of the lower leaves. The infection progresses up the plant until the entire plant turns yellow. Plants become stunted when infected at a younger age.
To be sure that the plant is infected by Fusarium wilt, you make a lengthwise cut on the stem at the soil line, near the base. The cut has a dark-brownish vascular tissue starting about .03 cm below the bark. Or you pull an infected plant, and the roots are partially or totally reddish-brown in color.
Conditions that favor development
- Infested planting materials
- Infested soil
Prevention and control
There is no known effective method to control Fusarium wilt. The following are the preventive measures to cushion the impact of the disease;
- Plant wilt-resistant cultivars whenever possible. Ask for assistance from your local agriculturist office.
- Practice a proper crop rotation strategy. If your soil is severely infested, planting solanaceous and other susceptible crops is not advisable.
- Whenever practical, remove and destroy infested plant materials after harvest. However, do not put these into your compost pit or pile. Compost from such materials will contain the fungi.
- Grow healthy plants with appropriate fertilization, irrigation, and weed control.