International solutions to Control Yellow and Black Sigatoka
Black Sigatoka (black leaf streak) and Yellow Sigatoka (leaf spot) are caused by the fungi Mycosphaerella fijiensis and Mycosphaerella musicola, respectively.
Yellow Sigatoka takes its name from the Sigatoka valley in Fiji where the disease was first recognized in 1912. During the next 40 years, the disease spread to all banana growing countries, making it a classic global disease epidemic. At the time it was the most serious leaf disease of bananas. Today Black Sigatoka is the most aggressive disease.
Black Sigatoka Life cycle
Black Sigatoka is the most serious foliar disease in bananas. Under optimal conditions it can advance through a complete life cycle in only 21 days. Damage from this disease causes a significant reduction in the photosynthetic area of the leaf. Losses in fruit yield can reach 50 through premature maturation, a very serious problem in fruit grown for export.
Black Sigatoka has its origin in the Pacific region and was reported in 1963 in Fiji. Since then, it has spread to many countries in the South Pacific and South East Asia. In Africa it was identified in 1973 in Zimbabwe and then spread across East and West Africa. In 1973 the fungus appeared in Central America, specifically in the area of La Lima, Republic of Honduras. It reached Belize in 1975, Costa Rica in 1979 and Panama in 1980. It has since reached other banana producing countries in South America.
Chemical control of Sigatoka began in the 1930s with applications of Bordeaux mixture. This was gradually superseded by other fungicides, such as the dithiocarbamates, benzol-derivatives, morpholines, benzimidazoles and triazoles. Baycor" and Folicur" are two well-known Bayer CropScience fungicides belonging to the latter group and have been used successfully over many years for Sigatoka control.
More recently, strobilurms were introduced and from this fungicide family Bayer CropScience has launched Tega" (trifloxystrobin), the most effective strobilurin available in bananas.
With the launch of two new fungicides from new chemical families, Impulse" and Siganex", Bayer CropScience has introduced two new options for disease control in bananas. These new products complete Bayer CropScience's fungicide portfolio in bananas, offering the most innovative, technologically advanced and diverse fungicide range available for the control of Sigatoka.
Fungicide Resistance Management
Due to the highly negative impact of Black Sigatoka disease on banana yield and quality, intensive and highly-developed spray programs are needed to control the disease. Under these circumstances it is very important to avoid and manage potential fungicide resistance risks. Spray programs need to be adapted to the local cropping and epidemiological situation. Resistance monitoring of the different fungicide groups is essential.
Bayer CropScience invests resources every year to monitor and find the best solutions to manage resistance issues. Bayer CropScience is also an active member of the different FRAC (Fungicide Resistance Action Committee) Working groups.
You can find the latest FRAC recommendations at the following Internet address: www.frac.info/