Major diseases of Lemongrass (Cymbopogon citrates) in North East India

Sushanti Thokchom and Tasvina R. Borahand Akoijam R. Singh


Cymbopogoncitratus (Lemon grass) is a widely used herb in tropical countries, especially in Southeast Asia. The essential oil of the plant is also used in aromatherapy and is one of the most commonly used plants in the folk medicine of native tribes of northeast India. Lemongrass offers multiple health benefits including reduction of bodyinflammations, relieving anxiety, lowering cholesterol, boosting oral health, red blood cell levels, etc. As such lemongrass has become an important ingredient in most of the continental culinary and tea of lemongrassis considered a beneficial drink by the health conscious population of today’s world. Considering the above facts,the large scale cultivation of lemon grass has been initiated to a great extent in North Eastern states of Indiaand has become a source of livelihood for the people of this region. Plant diseases has always been a major constraint in the producton of crops. The occurrence of some major fungal diseases in lemon grass and their management practices arelisted below.

 

Leaf blight (Curvulariaandropogonis)


The fungus affects the crop in the beginning of monsoon. Small brownish spots appear initially during the month of July, which enlarge into long patches along the tips and margins of the leaves. In case of serious infections, the entire leaves dry up resulting in considerable decrease in leaf and oil production. Warm and high humid conditionfavour the disease. The disease can be managed by spraying Mancozeb.

 

Collar rot and wilt (Fusariummoniliforme) 


The symptoms appear as rotting at collar region and wilting of plant. Spraying of Carbendazim 50WP (0.1%) twice at 7 days interval can be effective to manage the disease.


Rust (Puccinianakanishikii) 


Initial symptoms are tiny, light yellow spots that develop into brown spots and elongated, stripe-like, brown lesions that coincide with leaf veins and develop on both sides of the leaf. Lesion development can be substantial, with coalescing lesions forming large leaf spots or blights and causing premature death of leaves. The principal negative effects of lemongrass rust on the plant are defoliation and poor leaf and oil yield. The rust disease is normally not fatal to lemongrass plants, even though defoliation may be severe. Conditions favoring disease development are high rainfall, high humidity, and warm air temperatures. 

 

Integrated management practices 


•    Use of composts, mulches, and fertilizer to stimulate plant growth. 


•    Avoid planting large numbers of lemongrass close to one another. 


•    Do not purchase or distribute rusted plants. 


•    Periodically prune, cut back, or thin out diseased lemongrass plants so that disease free re-growth can occur.


•    Destroy diseased plant material (do not use it around pruned lemongrass plants as mulch). 


•    Keep weeds under control to reduce relative humidity in the lemongrass plant canopy. 


•    Plant lemongrass in well drained soils in a relatively dry or well ventilated area to minimize the time of leaf wetness after rainfall.


•    Minimize overhead irrigation, lemongrass grows well in dry areas.

 

Sushanti Thokchom is JRF at ICAR Research Complex for NEH Region, Umiam, Meghalaya

 

Tasvina R. BorahandAkoijam R. Singh is a Scientist at ICAR Research Complex for NEH region, Umiam, Meghalaya