Corcyra cephalonica Stainton

Bold white sorghum grains meant for human consumption is procured. The sorghum should not be treated with insecticides (to test this a sample containing 100 gms from each bag is crushed and 20-1st/2nd ins tar Corcyra larvae are allowed to feed for 2-3 days to find out whether the sorghum has previously been treated with any of the insecticides. The conclusion could be drawn based on the mortality of the larvae).

The required quantity of sorghum is milled to make 3-4 pieces of each grain. It is heat sterilized in oven at 100°C for 30 minutes and is sprayed with 0.1% formalin. This treatment helps to prevent the growth of moulds as well as increases the grain humidity, which was lost due to heat sterilization. Then it is air dried and poured @ 2.5 kg / box.

To start with, 600 boxes (containing 2.5 kg of sorghum/box) are infested with 300 cc of Corcyra eggs, and the lid is secured for about 30 days. Later on infestation is done at the same ratio on 45th, 90th, 135th, 180th and 225th day. On 270th and 315th day only 200 boxes each are infested. The first lot of 600 boxes is kept in racks and the lids closed. (the same procedure is followed for subsequent lots) On 40th day moths start emerging and the emergence continues for about two months. 10 to 75 moths emerge daily with the peak of moth emergence being between 65th and 75th day.

The moths are collected daily and transferred to the specially designed oviposition cages. Moth emergence reduces after 100 days of initial infestation and boxes are reused after cleaning. Eggs which pass through 15, 30 and 40 mesh sieves are collected and run over a slope of paper to eliminate dust particles. The-eggs are treated with UV rays (15Wt UV tube for 45 minutes at a distance of 2 feet) to prevent hatching.