Mango is the most important fruit crop in the tropical region. It has a high potential for-profit and foreign exchange provided quality mangoes are produced. After fruit set the mango stone/nut weevil cause 40 to 60 % loss in fruit(as fruit-drop and fruit-pulp damage). The stone weevil is a major hindrance in the processing industry and the export market.
The scientists from the Indian Institute of Horticulture have worked out cost-effective and residue-free control strategies for the Integrated Pest Management of Stone Weevil and the technical know-how is as follows.
What are Mango Stone weevil?
Mango stone weevil is the brownish adults about one cm in length and rest between July & February(Off Season) on mango trunks. When fruits are the lime size they lay eggs on fruit. The grubs which hatch bore into the seed, and feed within. On completion of the life cycle, they exit through the pulp thereby spoiling it. Adults cause loss to farmers and are a hindrance to the export and processing industry.
How do you get rid of Stone weevils in Mango?
Integrated pest managemnet is followed to get rid of Stone weevils in Mango
- The adults spend nearly 6 to 8 months in hiding in junctions of trunk and primary branches between July and February where mud and leaf litter gather and decompose. A good cultural method to control the weevils is to clean these junctions with a hard broom any time after July/August. This may be repeated in December/January.
- When any chemical sprays like imidacloprid are given for hopper(Idioscopus or Amritodus) control, farmers should ensure good coverage on the trunk, branches, and canopy. Not only this would control the hoppers(even those hidings in the barks) but also kill resting adult stone weevils.
Note: Adult weevils rest on mango trunk junctions approximately from July to February).
- When 50 percent of fruits have attained ‘lime size’ (2 to 4 cm diameter) give a spray of acephate 1.5g/l followed after two weeks by deltamethrin 1ml/l.
Note: Wherever fruits are intended for export, avoid acephate and instead give two sprays of deltamethrin.