EFFICIENCY OF ORGANIC AND INORGANIC PESTICIDES AGAINST STORED GRAIN INSECT PESTS

The insect pests cause substantial loss of grains in the field and during storage of food grains that worth millions of rupees. Hence, in order to manage stored grain insect pests a combination of organic and inorganic pesticide control materials was selected to check the efficiency against red flour beetle (Tribolium castaneum) and pulse beetle (Callosobruchus chinensis). Total 10 treatments were used, eight different organic bio-pesticides (neem seed, neem leaves, naswar, tobacco, eucalyptus, citrus, dhatura and mint) and one inorganic (naphthalene balls) and control used at 32 ± 2°C and 70 ± 5% RH. The results indicated that three doses of all treatments were used as 5, 10 and 20gm in 50gm grains. Overall, maximum (4.33 ± 1.00%) mortality of red flour beetle was observed using neem seed powder and no (0.0 0 ± 00%) mortality was observed in minte leaves powder. In case of pulse beetle, the maximum (5.07 ± 0.87%) mortality was observed using neem seed powder and minimum (0.66±0.22%) using citrus leaves powder. Maximum (16.26 ± 0.03) antifeedant efficiency of red flour beetle was observed in control group and minimum (6.46±0.65) antifeedant efficiency of red flour beetle was found in dhatura leaves powder at all tested concentrations. Maximum (14.23 ± 0.13) antifeedant efficiency of pulse beetle was determined in control group and and minimum (1.00 ± 0.04) was observed for naphthalene balls at all tested concentrations. Maximum (94.67%) repellency against red flour beetle was observed using neem seed powder and minimum (62.00%) was found in naphathalene balls as compared with their controls. Maximum (81.32%) repellency against pulse beetle was observed using naswar powder and minimum (63.34%) repellency was determined using neem leaves powder as compared with their control group. We concluded that 20% of neem seed powder concentration proved effective to suppress the population of both red flour beetle and pulse beetle.

Efficacy of Entomopathogenic Nematodes Against Three Species of Stored Product Insects

Two specis of entomopathogenic nematodes (EPNs), Steinernema riobravi, symbolized by Sr, and Heterorabditisbacterophora, symbolized by Hb,were tested by using five concentrations: 125, 250, 500, 1000, and 2000 an infectiousphase, ml of the type Sr and four concentrations of 500, 1000, 2000 and 3000infectious phase/mlof the type Hb against Cowpea weevil, Callosobruchus maculates,Khapra beetle, Trogoderma granarium, and Rust red flour beetle Triboliumcastaneum, using three exposure times of 24, 48, and 72 h. The mortalityrate increased withincreasing in concentrations and the exposure period. The results showed that the highest mortality rate was 16.67 whole insects recorded for the 2000 infectious phase/ml with Sr nematodes after 72 hours post- treatment ofC. maculatus. The results showed that the highest rate mortality,which is 20 larvae, was recorded for the infectious phase dose of the genus nematode (Hb), all of which are 500, 1000, 2000 and 3000 gastricphase/ml, and for all exposure periods used between 24 hours and up to 72 hours against the larvae of the T. granarium. The results showed that the highest rate of mortality 10.00 whole insects was recorded for the dose of 3000 Infectious stage/ml and at the exposure time 72 hours, while the lowest rate for this mortality of 1.33 adult insects for rusty flour beetle was recorded for the dose of 500 infectious stage/ml and for the exposure time only 24 hours. The resultsindicated that mortality rate was increasing against any increase in both the exposure time and the dose of nematodes of the genus Hb.

Eco-friendly Approach for the Management of Rust Red Flour Beetle, Tribolium castaneum (Herbst) on Wheat Grains

Background: Wheat is the major cereal crop occupying an eminent place in economy of our country. About 10-15% wheat is lost annually due to ravages of stored grains pests during storage. The principal stored grain pest of wheat is red flour beetle Tribolium castaneum (Herbst) which is a cosmopolitan and most serious pest. Methods: The present investigation was carried out in the Entomology Laboratory during 2020-2021, College of Agriculture, Central Agricultural University, Imphal to investigate eco-friendly management of rust red flour beetle, Tribolium castaneum on wheat grains by using different inert materials viz., paddy straw, paddy husk ash, cow dung ash, coal ash, sand dust, saw dust, boric acid and one untreated control with the dose of 1.5 gm/100 gm of wheat grains. Result: The results showed that the boric acid exhibited 100 per cent adult mortality of T. castaneum within 5 days after treatment. Afterwards the next best treatment was cow dung ash, coal ash shows the very effective in treatment in the adult emergence and grain weight loss. Whereas, saw dust shows the least effective treatment in the controlling adult emergence.