Lesser grain borer, Rhyzopertha dominica infests speciality food crop makhana, Euryale ferox in India

Abstract

Makhana is a popular popped snack in south-east Asia due to its high nutritional value. During storage of roasted makhana seeds, Rhyzopertha dominica found feeding which later found affecting significantly the popping quality. Detailed study elucidated that adults preferred 11 mm size seeds, average 2 grubs and 1 adult per seed was found feeding inside, wherein they bored ∼2 holes, apart from natural hole and caused 49.3% damage in 75 days storage. With an artificial infestation of 150 adults per kg of seed, recorded maximum damage (46.80%) with 4.77 mg of seed dust produced. Insect successfully completed its life cycle on roasted makhana seeds in 100-125 days. Female laid 242 ± 7 eggs at 28 °C, and 210 ± 11 eggs at 32 °C. The infestation led to significant change in seed quality like popping, moisture, ash and crude fibre. The commonly available management strategy like UV light trapping was done, and peak attraction was reported at 8 pm (27%). Study showed feed preference, biology and management option, which can be useful for devising the insect management in makhana storage.