Fungicide for a Tomato Plant


A variety of fungal infections may cause significant crop losses and visible injury to your tomato plant garden. While proper care is essential, certain pathogens and particularly severe infections benefit from the chemical control offered by fungicides. Get to know some common problems as well as those fungicidal management options for a healthy home-tomato garden.


Providing consistent maintenance creates vigorous tomatoes that are more likely to resist or fight off fungal infections than those tomatoes in weakened or injured states. Grow your tomatoes in locations that provide full sun exposure for optimal production. Tomatoes grow best in soil high in organic content like compost; the ideal pH range is 6.5 to 7.0, according to the University of Missouri Extension.


Fungicides are often necessary for use on tomato plants due to common infections that can destroy crops. Septoria leaf spot, for example, is caused by the fungus Septoria lycopersici and is well-known for its attacks on tomatoes, according to the Iowa State University Extension. Anthracnose, as well, attacks a wide variety of plants including tomatoes and is caused by the fungus Colletotrichum coccodes. Both of these fungal problems are treatable with fungicides.


When left untreated, septoria leaf spot results in the appearance of small spots that appear saturated with water on tomato foliage. Spots turn into larger lesions where fungal growths form. This disease leads to the yellowing, death and drop of leaves. Anthracnose on tomatoes first appears as sunken spots on fruit skin that darken and display fungal growths. This problem leads to the rotting of fruit flesh and, in severe cases, total decay of fruit. Fungicides prevent total destruction to your home garden.


Though fungicides are used as a chemical treatment for fungal infections on tomato plants, realize that they are only one part of dealing with infectious diseases. Cultural control is an essential aspect used in conjunction with fungicides to offer your tomatoes the greatest protection. Always keep tools sanitized between each use on plants and from one plant to the next to reduce the spread of disease. When appropriate, remove and destroy affected plant parts. Additionally, planting resistant varieties to different types of fungal infections greatly reduces your tomato plant's risk of infection. Contact your local county extension agent for advice on the best varieties for your particular region.


Different formulations of chemical fungicides offer control of different fungal diseases. For example, when treating septoria leaf spot on your tomato plants, apply a chemical with the active ingredient azoxystrobin or mancozeb zoxamide. While azoxystrobin is also effective on anthracnose, mancozeb zoxamide is not. For additional athracnose control, apply a fungicide with the active ingredient chlorothalonil which also treats septoria leaf spot, according to Purdue University. Research each fungicide before application to ensure its formulation for use on tomato plants and for the appropriate disease.

Keywords: tomato plant fungicide, tomato plant fungus, tomato fungicide control

About this Author

Tarah Damask's writing career, beginning in 2003, includes experience as a fashion writer/editor for Neiman Marcus, short fiction publications in "North Texas Review," a self-published novel, band biographies, charter school curriculum, and articles for eHow. She has a love for words and is an avid observer. Damask holds a Master of Arts in English and creative writing from the University of North Texas.