A survey of Sigatoka leaf disease (Mycosphaerella musicola Leach) of banana and soil calcium levels in North Queensland

Abstract

Annual averages of lesion development of yellow Sigatoka caused by Mycosphaerella musicola were calculated from surveys conducted at 14-day intervals for 57 banana sites in the North Queensland production region situated in the wet tropics between Cardwell and Innisfail. Soil up to 250 mm depth was sampled from sites between March 2000 and September 2001. Soil parameters were compared with 12 months of leaf disease data averaged centrally about the time the soil sample was taken. The 4 different formulas for calcium expression tested all proved to be significant predictors of disease levels. The strongest relationship (r2 = 0.229) between soil calcium levels and disease levels was obtained from a formula based on an Albrecht interpretation of the soil test data, which includes a pH-derived estimation of exchangeable hydrogen in the denominator. A Chi square analysis on a model incorporating calcium and soil boron was statistically significant (P<0.001). The model combining calcium and boron levels explained more variation in disease levels than calcium alone. Variation in other factors influencing disease such as fungicide program, weather conditions, soil moisture conditions and crop stage may account for variation in disease levels at low calcium sites.

Spatial distribution of Yellow Sigatoka Leaf Spot correlated with soil fertility and plant nutrition

“…According to Huber et al (2012), the mechanisms by which calcium affects the incidence of plant diseases are related both to recognition of pathogens invading the plasma membrane and to the stability of cell walls and biomembranes. Only the study of Gerald et al (2003) reporting a reduction in Yellow Sigatoka in areas with higher levels of Ca was found in the literature; however, the importance of Ca in reducing several other pathosystems has been reported. These include coffee (Coffea arabica/coffeicola Cercospora) (Garcia Júnior et al 2003), citrus (Citrus paradisi/Mycosphaerella citri) (Mondal and Timmer 2003) and oak (Quercus ilex/Phytophthora cinnamomi) (Serrano et al 2013).…”

Interaction between potassium (K) and calcium (Ca) on the severity of Yellow Sigatoka in banana plants

“…In the case of banana plants, the intensity of Yellow Sigatoka was higher in plants grown in K-deficient nutrient solution (Freitas et al, 2015b), and lower in plants grown in soil with higher contents of Ca (Freitas et al, 2015a;Gerald et al, 2003).…”