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.

Stored Grain Pests and Current Advances for their Management

During the offseason, when fresh food is not available, humans have to consume stored grain food. Unfortunately, these stored grains are later infested with many pests. Foods stored in bags and bins are very much susceptible to infestation with several pests which can cause extensive post-harvest losses, spoilage, and less demand in markets, causing a huge economic crisis. Hence, successful management of stored grain pests becomes necessary to prevent these from insect pests. Current approaches for their management are one of the promising goals, as it includes preventive practices, monitoring, sanitation, and identification of main pathogens. Different management strategies of all the common stored grain pests viz. grain weevils, grain borers, grain moths, flour moths, mealworms, grain and flour beetles, booklice, mites, and parasites are enlisted here.

Pathogenicity of Pakistani isolates of Steinernema bifurcatum and S. affine (Rhabditida: Steinernematidae) in management of stored grain pests Lasioderma serricorne and Tribolium castaneum (Coleoptera: Ptinidae, Tenebrionidae)

Background Stored grain products suffer a considerable economic loss due to insect infestations. The resistance of pests to insecticide, and residues on crops are produced by the application of insecticide. Nowadays, incremental necessity has been occurred to find out alternatives to chemicals. As biological control agents, entomopathogenic nematodes (EPNs) attract attention increasingly in the research area recently. Results The aim of the study was to evaluate the pathogenicity of Pakistani isolates Steinernema bifurcatum and S. affine against the stored grain pests, Tribolium castaneum and Lasioderma serricorne, under laboratory conditions. Suspensions of nematodes were applied at 4 different concentrations 0, 50, 100, and 200 IJs/ml and 3 variable temperatures 15, 30, and 45°C. Pathogenicity rate was recorded after 48 h of application. The larval stage is found more susceptible than the adult. At 200 IJs, S. bifurcatum showed high mortality of L. serricorne larva (92%) and T. castaneum larva (93%), whereas S. affine showed 90 and 95% mortality of L. serricorne and T. castaneum larva, respectively, at 200 IJs. The results revealed that both species of EPN were able to control and reproduce on L. serricorne and T. castaneum. Maximum mortality was recorded at 45 °C from S. bifurcatum whereas S. affine at 15 °C. Conclusions Therefore, S. bifurcatum and S. affine could be suggested as a biological control agent for hot and cold climatic zones, respectively.

Volatiles Play an Important Role in the Attractiveness of Food for Trapping the Stored Grain Pests Oryzaephilus surinamensis L. (Coleoptera: Silvanidae)

The Oryzaephilus surinamensis L. (Coleoptera: Silvanidae), is widely distributed all over the world, this beetle causes serious damage to stored products. Much attention has been paid to use food attraction or food volatile as a non-pollution method to achieve pest management. However, in this study, six most attractive food to O. surinamensis were selected among thirty eight food. Furthermore, the food mixture M17 with the best attractiveness were selected among the eighteen food mixtures combined by these six foods at different ratio. Subsequently food mixture M17 were tested in actual barn and compared with commercial attractant. We collected the volatile from food mixture, the volatile compounds attractive to this beetle also. We identified six electrophysio-logically active compounds responsible for the attraction of O. surinamensis, among the six chemically identified compounds, nonanal, dodecane, tridecaneand β-caryophyllene significantly attracted O. surinamensis when tested individually in behavioral assays. Blend of six chemicals according to food volatile concentration was most attractive to the beetles. The findings of this study reveal that food mixture M17 and food volatile can be potentially used for development of effective attractants for management of O. surinamensis.

Fumigation Activity against Phosphine-Resistant Tribolium castaneum (Coleoptera: Tenebrionidae) Using Carbonyl Sulfide

Phosphine resistance is occurring among stored-grain pests worldwide. This study investigated the fumigation activity of phosphine (PH3) and carbonyl sulfide (COS) against domestic strain (d-strain) Tribolium castaneum, resistance strain (r-strain) T. castaneum and Oryzaephilus surinamensis. All developmental stages of the pests were exposed to two fumigants (PH3 and COS), and the fumigation activity according to the dose and exposure time was evaluated in a 12-L desiccator and 0.5 m3 fumigation chamber. The rice sorption rate and quality following exposure to thetwofumigants were evaluated. The mortality was 2.9% in r-strain T. castaneum, 49.5% in d-strain T. castaneum and 99.2% in O. surinamensis when 2 mg/L PH3 was used in a 12-L desiccator for 4 h. However, all pest developmental stages showed 100% mortality after 24 h of exposure in the 0.5 m3 fumigation chamber, except for the r-strain T. castaneum. A mortalityof 100% was observed in all of the r-strain T. castaneum developmental stages at an exposure time of 192 h. For COS applied at 40.23 mg/L and 50 g/m3 in the 12-L desiccator and the 0.5 m3 fumigation chamber, respectively, 100% mortality was observed across all developmental stages regardless of species and strain. The sorption of COS was 10% higher than that of PH3, but there was no significant difference in rice quality compared to that in the control. Therefore, this study suggests that COS can be used for controlling T. castaneum resistant to PH3.