Evaluation of Some Botanicals against Callosobruchus chinensis L. Infesting Stored Chickpea Seeds and Bio-Chemical Analysis of Used Botanicals

A study was carried out to evaluate the bio-efficacy of some botanicals against Callosobruchus chinensis L. in stored chickpea (Variety: Anuradha) in the year 2018–20. Different botanicals like Neem (Azadirachta indica), Melia (Melia azedarach), Datura (Datura stramonium) and Tulsi (Ocimum sanctum) were used. Among all the botanicals Neem leaf powder @ 6% performed better with minimum egg laying (64 eggs 5 females-1) compared to the other botanicals except the standard check with Deltamethrin @ 0.04%. Thereafter, 6% Melia leaf powder and 8% Datura leaf powder recorded 87.50 eggs 5 females-1 and 91.25 eggs 5 females-1, respectively. With regard to adult mortality, the best result was also obtained from the treatment Neem leaf powder @6% with 96.67% mortality in 5th day. Following the same trend, 6% Melia leaf powder and 8% Datura leaf powder exhibited 90% and 83.33% adult mortality, respectively, in 5th day. The estimation of total phenols and total antioxidants (IC-50) contents in Neem leaf powder (345.69 mg g-1 and 207.77 μg ml-1), Melia leaf powder (273.40 mg g-1 and 383.68 μg ml-1) and Datura Leaf Powder (213.62 mg g-1 and 405.77 μg ml-1) also confirms the findings of the bio-efficacy trial of the botanicals. Tulsi leaf powder @5% was least efficacious both in terms of egg laying by the females as well as adult mortality. These botanicals are locally available, economic, bio-degradable and safe to the environment. Therefore, they may be fitted in the Integrated Pest Management strategies against stored grain pests as seed protectants.

Susceptibility of different life stages of Callosobruchus maculatus and Callosobruchus chinensis to ECO2FUME gas and its impact on cowpea seeds quality

ECO2FUME gas is an alternative to toxic phosphine fumigant and as a quarantine treatment for the control of a particularly recalcitrant pest, Callosobruchus maculatus and Callosobruchus chinensis. This gas was used to fumigate stored cowpea piles under gas-proof sheets to assess its performance against different developmental stages of Callosobruchus maculatus and Callosobruchus chinensis. The mortality was determined on four developmental stages of C. maculatus and C. chinensis, employing ECO2FUME at different concentrations 25, 30, 40, and 50 g/m3 for 3-days. All stages of both insect species in packed cowpea stacks were completely controlled at 3-days when applied with an ECO2FUME application rate of 50 g/m3. Cases of pupae of C. maculatus and C. chinensis exhibit the highest resistance than other stages, with 78.2 and 73.93% mortality respectively, at 40 g/m3 after 3-days post-exposure to ECO2FUME. Suppression of F1 generation was obtained after fumigation with the same concentration (50 g/m3). Quality (in terms of cowpea germination) and all chemical constituents of cowpea seeds were non significantly (P≤0.05) affected by the fumigation concentration of 50 g/m3.

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.

Insecticidal potency of mixtures of plant powders and Actellic SuperTM (Pirimiphos-methyl + Permethrin) on Callosobruchus chinensis F. and Sitophilus zeamais Motch

Insect pests still cause substantial quantitative and qualitative grain loss ranging from 20 to 100% in small holder farming systems in tropical countries. Synthetic pesticides are recommended as stop gap measures for the management of stored product insect pests. However, their application has not been fully exploited in small scale farming due to environmental, health, and economic concerns. As a result, new researches have shifted focus to exploiting pesticidal plants as alternatives to synthetic pesticides. Therefore, the current study evaluated mixtures of plant powders and reduced amount of Actellic superTM (pirimiphos-methyl + permethrin) as alternative insecticide formulation against Callosobruchus chinensis and Sitophilus zeamais. Green grams and wheat grains were mixed with a mixture of plant powders in the ratios of 1:1, 1:3 and 1:9 to obtain four rates (0.0, 2.0, 6.0 and 10%w/w). Grains and plant powders were also mixed with reduced amount (10, 25, and 50 %) of recommended rate of Actellic SuperTM to obtain dosages as above. Twenty unsexed adults, 1-5 day old S. zeamais and C. chinensis were introduced into treated grains. The mixture of C. lusitanica: T. vogelii powders in the ratios of 1:1, 1:3 and 1:9 caused mortality in C. chinensis of 55, 95 and 85%, respectively. At the same ratio, E. saligna: L. camara mixture produced mortality in S. zeamais of 77, 82, and 85% respectively. In mixture of C. lusitanica and T. vogelii and reduced amount of Actellic SuperTM by 50% the mortality of C. chinensis was 85 and 80 % respectively. Similarly, E. saligna and L. camara and reduced amount of Actellic SuperTM by 50% caused a mortality of S. zeamais of 48 and 97% respectively. The application of plant powders and reduced amounts of synthetic insecticide has the potential to be applied in stored product pest control