How to Effectively Suppress Leaf Spot of Ginger

(by. Dr. Dyah Manohara)

Bacterial wilt caused by Ralstonia solanacearum is still a problem in ginger cultivation in Indonesia. But lately, leaf spot symptoms have been reported to be an important issue in some ginger production centers in West Java, Central Java and Bengkulu. There are four types of fungi are widely reported to cause damage to the leaves of the ginger plant in Indonesia, namely Phyllosticta, Pyricularia, Cercospora and Phakopsora.

In 2009, ISMCRI has conducted screening ginger accessions resistance to Pyricularia and Cercospora fungus; evaluation of the effectiveness of fungicides (botanical and synthetic) against Pyricularia fungus in vitro in the laboratory; evaluation of the distribution of the host fungus Pyricularia on some Zingiberaceae plants. The results of the study in 2010 showed that the combination of K fertilizer (400 kg/ha) and Mg (300 kg/ha) increase plant resistance to leaf spot attack with rhizome production of 413.33 kg/clump.

Application of synthetic fungicide (Mancozeb fungicide) was more effective in suppressing leaf spot attacks, when compared to botanical fungicides (including clove botanical pesticide and fragrant lemongrass botanical fungicide). In 2011, already tested the effect of the combination of fertilizer (K and Mg) and Mancozeb fungicide application (two-and three-week intervals). The results showed that the application of the two-week intervals is better than a three-week intervals.

In 2012, already tested a combination of fertilizer (K and Mg) and Mancozeb fungicide applications at intervals of two weeks to two accessions of ginger (tolerant and susceptible leaf spot), on a field scale in endemic areas leaf spot disease. The results showed that the combination of fertilizer (400 kg/ha KCl and 300 kg/ha MgSO4) and fungicide applications at intervals of two weeks can reduce the intensity of leaf spot by 56% in the ginger accession JPK H. This treatment is also capable of producing rhizomes at 816,79 g. Fertilizer treatment of 300 kg/ha KCl and 100 kg/ha MgSO4 on JPK H was able to improve the quality of the resulting rhizomes. Without fungicide applications, JPK H yield of 785.06 g rhizome, with fungicide application intervals of two weeks, the intensity of leaf spot decreased by 44.77% and JPK H produces rhizomes of 796.34 g with levels higher than the gingerol without fungicide application. 

Source : Indonesian Spice and Medicinal Crops Research Institute