Tree-killing disease threatening to wipe out Boko orange groves in Assam

Four years back, Athone Sangma (59) an orange grower of Hantaikona village, 40 km off Boko town in Assam’s Kamrup district used to supply up to one truck load of famed Khasi Mandarin variety to fruit market in Guwahati daily during September to January. During the peak season Sangma used to earn to the tune of Rs. 3 to 4 lakh a year from about 5000 orange plants in his 80-bigha plot of garden. He has not been able to supply oranges as the trees of his gardens hardly bear any fruit owing to some diseases.

Not just Sangma, about 5000 orange growers of lower Assam’s Boko area, famous for the citrus variety, have been facing crisis and this special variety is now on the verge of being wiped out from the area. Meghalaya is famous for Khasi mandarin (Citrus reticulate ), a popular orange variety of the country.

“I have been reduced to rags over the last three to four years after all the plants in my garden have been hit by diseases,” laments Sangma.

Photo - Kishore Talukdar

Sharing his observation of the infected plants, Sangma says, “Initially the crown leaves of the plant turn yellow. Then whole plant gradually dries up and finally it withers completely.”   

“To explore more about the disease, I weeded out the roots of the infected plants and observed that the roots were decaying and stinking. To save the plants I spent Rs 80,000 for application of medicines and other treatments but in vain. Unable to get any result, I have abandoned growing oranges for four years now,” tears rolled down Sangma’s cheeks, as he narrates his sorrows.

Members of a team of experts from New Delhi, who visited his garden in 2014, were also shocked to observe the orange crop devastation. Having grown oranges for 27 years, Sangma was finding it difficult to abandon growing the fruit and, therefore, planted new orange plants in a bid to revive his garden. But all his efforts were in vain as the new plants too were infected. Sangma has now started exploring growing other horticulture crops like banana, areca nut, pineapple etc.

Photo - Kishore Talukdar

Orange cultivation area under Boko Agriculture Sub Division spreads over 3226 hectares.  In the three circles-Chhaygaon, Boko, Bongaon-disease has so far destroyed 1,300 hectares area of orange cultivation. With the disease spreading like wildfire, bleak future is looming large over about 5000 orange growers of the area.

“Normal yearly output of the area is about 6,030 Metric Tonne which has now declined by about 40 percent.” Agriculture Department sources say.

Girish Baruah of Nalakhat near Bamunigaon has also experienced devastation of his orange crop by disease. About 100 plants of the total 550 plants in Baruah’s 5.5 bigha garden have already been destroyed by the disease. “The 8 year old plants started to die just after flowering. Fruit output has also declined. Every year the problem is getting aggravated but the department has done nothing to combat the disease,’ alleges Baruah.   

Bhadeshawr Boro, Project Assistant of Centre of Excellence, Citrus, Bamunigaon says they cannot supply medicine without scheme. “The menace which has already taken heavy toll warrants in-depth exploration to arrest its further expansion. We have to take immediate steps to preservation of the mother plant of this quality orange variety of the country,” Boro says.

Photo - Kishore Talukdar

Agriculture department has attributed the crop devastation to poor management, poor nutrient supply and non replacement of aging plant which are more than 30 years old. However, Athone is unwilling to buy the view of poor management as only cause of disaster and insisted that he had taken all possible measures to save the plants. “I had four permanent night watchmen to man the gardens besides 15 to 20 casual workers, who are engaged in cleaning activities,” Athone says.

Now, Athone has explored the potential of pineapple, areca-nut and banana farming but economic hardship due to failure of orange crop has posed a big challenge for him. “The government should now partonise us to resume professional farming as we have incurred losses over the past four years,” Athone insists.

Agriculture Development Officer of Bongaon Revenue Circle, Bipul Kumar Nath expresses concern over the development and says that  the department would soon launch an awareness drive in this regard. He says that quality of oranges has also deteriorated and the situation demands urgent intervention. 

Photo - Kishore Talukdar

However, N. K Mazumdar, principal scientist of Horticulture Research Station of Assam Agriculture University attributes the crop failure to inadequate farm management. About the crown leaves of the plant turning yellow, Mazumdar says if the root of a particular orange plant starts decaying the symptom initially finds reflection in the leaves which start turning yellow.  Another external symptom is oozing of brown colour gum-type material from the infected plant. It is called gummosis disease which is caused by soil-borne fungal pathogen. The disease spreads if preventive steps are not taken at the initial stage. The disease spreads easily through the hair roots of the infected plant because of the close proximity of the root zones between the plants. The pathologist prescribed uprooting and destruction of dead plants by burning to successfully check spread. Soil treatment after the burning is very important. “Once the soil is treated adequately including the bio agents, farmers should go ahead with planting material anew. Otherwise burning of infected plant with whole root system will not be effective without treating the soil adequately,” Mazumdar says. The pathologist also made suggestion to keep the healthy plant uninfected. The pathologist says as per fungicidal solution, application of pest at collar region up to 1 meter height of the healthy plant is required to keep the disease at bay.

Photo - Kishore Talukdar

Mazumdar rues that the framers are reluctant to spare a share of their profit for the plant which earns them a handsome amount. “It is all about management and plantation of good material and adoption of recommended package of practice for optimum output,” he adds.

Kishore Talukdar

(Kishore Talukdar is an independent journalist based in Guwahati. His areas of interest include Development journalism and Environment journalism. He can be contacted at [email protected] )