Description of the survey area and collection procedures of samples & data The study was carried out in the three major maize grown area of Bangladesh viz Rangpur, Bogura and Kushtia during July, 2017 to December, 2017. To find out the post-harvest problems of maize cultivation, 20 farmer’s opinions were collected from each survey area through a well-structured questionnaire and also to find out on-farm post-harvest losses of maize in the research area, 1kg of maize was collected from 20 farmers of each selected area for the abundance of insect pest and their infestation. The samples of grains were obtained from as many different parts of the various storage facilities as possible (top, sides, centre, & bottom). Each sample was put in a paper bag and labeled with the necessary information for further inspection in a laboratory as per the methods used by Firidissa (1999). After the collection of samples, grains were sieved over a 2mm mesh sieve (Abraham, 1995) according to each sample of survey areas. Insects were removed, counted and grouped to order & family, and were preserved dry as pinned collections or in 75% ethanol for identification. Identification was made using a combination of insect identification keys, books, journals, handbooks, pictures, booklets, and comparisons with already identified specimens in the laboratory. Again, it was identified and confirmed with the help of specialized persons of the Department of Entomology, BAU, Mymensingh. Then, the rate of insect infestation was recorded from each sample of the selected areas.
Experimental Site, period and design The experiments were conducted in IPM Laboratory, Department of Entomology, Bangladesh Agricultural University (BAU), Mymensingh during July, 2017 to December, 2017. The experiments were laid out in Complete Randomized Design (CRD) with three replications. The experimental site is located at 24.75° N latitude and 90.5°E longitude at a mean elevation of 7.9 to 9.1 m above the sea level. It is situated under a sub-tropical climate, which is characterized by high temperature, high humidity and heavy precipitation with occasional gusty winds from April to September and scanty rainfall associated with moderately low temperature and humidity from October to March.
Maize grain, different types of containers, botanicals and bio-rationales used for the experiment Clean and well sieve size grain of variety BARI Hybrid Butta09 was used, which was obtained from Bangladesh Agricultural Research Institute (BARI), Gazipur, Bangladesh. The grains were cleaned of broken kernels and debris by hand and by using a 4.76 mm round holed sieve. The grains were graded manually and almost larger grains were used in the study. Before the experiment, the seeds were dried in oven at 500C for two days and frozen at -60C for seven days to kill any live insects on and in it. Then, 1 kg larger grains were used in each replication for the purpose of the containers experiment and 100 g grains were used in each replication for botanicals & bio-rationales experiment. Six different types of containers viz. Earthen pot, Gunny bag, Doll (made from bamboo), Plastic bag, Plastic pot and Tin kauta (made from steel) were selected as storage containers which was kept free from insect pest and pathogens. Five different types of botanicals viz. leaf of Neem (Azadrachtaindica), leaf of Biskatiali (Persicariahyddropiper), the mature seed of Mahogani (Swieteniamahogani), a clove of garlic (Allium sativum) and the mature seed of Pithraj (Aphanamixispolystachya)were used as botanicals for controlling insect pests and infection. Four different kinds of bio-rationales viz. Spinosad, Abamectin, Emamectinbenzoate and Lufeneuron were used as rationales.