Collaborative effort required to arrest Orange Fruit Drop

KC PRADHAN, a Concerned  Horticulturist

I read the editorial in NOW! [“Missing Bees”] on the decline in all major cash crops of the State with concern. It was horrifying to see the colossal amount of orange fruit drop in Dzongu as telecast in local cable news a few days back. Lum in Dzongu was considered a highly prized citrus growing belt immune to any serious diseases. This plight might be rampant elsewhere in the state as well.
Though the concerned Department might be already on the job, nevertheless, it is good for the people at large to know and to launch a massive campaign – rather a Panchayat-wise effort - to collate information on one hand and cultivators’ perception on the other without trying to influence information. This should help people at large invest in a brainstorming session in which both, the scientists assigned to the job and progressive growers, can have interactive sessions with a view to come out with a methodology in the best manner possible from the information gathered. Bhutan faces a similar situation and serious research is being carried out there with the help of outside expertise. The situation is too huge for the department officials alone to tackle and people’s participation is urgently required. The fallen fruits should be collected on a daily basis and maggots destroyed before they pupate underground to emerge as Fruit Flies in more damaging proportions. The whole cycle being less than 40 days, it is advisable to take it as an emergency campaign. Though it is the tail end, nevertheless it is worth a try wherever the situation still demands it.
The usual procedure as narrated in literature is to collect the fallen fruits and bury them in four feet deep trenches. The fruits collected in thick plastic bags, the tops tied and exposed to a full blast of the Sun has proven effective in destroying the maggots. It is also advisable for farmers to know the lifecycle of the Fly (Dacus dorsalis) so that they can devise their own methods to contain it. It is learnt an “adult fly punctures the ripening fruits by penetrating its needlelike ovipositor and laying eggs just inside the inner rind of the fruit. Larva on hatching feeds on the pulp inside. Fungal and bacterial infection takes place through the puncture hole due to which rottening of fruit occurs. The fruit ultimately drops down. This usually occurs when the fruits start ripening as the yellow colour attracts the Flies.
The female inserts 2-15 eggs into the rind of the ripening fruit, and around 200 eggs are laid in a month’s period which hatch in about 2-3 days during summer and 10 days in winter. The maggots take 16-29 days to attain full growth in the pulp and then undergo pupation 3-7 inches deep in the soil. The adults emerge after 4-14 days depending upon the climatic conditions”.
Such being the lifecycle of the Fruit Fly, unless it is systematically destroyed on a routine basis, soon it spell the end of Sikkim orange (mandarin) as it happened with Sikkim Apples with scab-disease some thirty years back.
Since an Organic Pesticide and Fertilizers manufacturing unit has been established in the State, it would also be well advised to put them on the job and to see how efficient it is. In most Citrus growing countries it is regular practice to spray chemicals to destroy the flies. But since Sikkim has gone Organic, it is vital that some effective organic pesticides are lined up well in time and importantly it is well publicized besides made easily available.
The efficacy of fruit traps that were supplied is also good to know along with farmers’ perception. ICAR and Krishi Kendras should also be roped in to contain this emerging menace that is being observed in Citrus. It is also important to understand and study the situation in citrus orchards outside the State.
Large Cardamom and Apples, as mentioned in the Editorial, are other areas that demand equally urgent attention. Before such a meet is held it is important to understand the exact state of affairs on the field, the various programmes already in action both by the Department and the Central Govt. agencies based in the State, the synthesis of which, have to be combined with the stakeholders with a view to come up with a well conceived and unanimously accepted and endorsed line of action. This participatory approach alone is the answer to these rather vexing problems.