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Plant based insecticides are considered among the most economic and ecofriendly chemicals for the protection of plants and stored grains. The cowpea weevil (Callosbruchus maculatus) causes more than 90% damage to sored grains in three to six months. The current study investigates insecticidal potentials of five selected botanicals: Melia azedarach, Nicotiana rustica, Azadirachta indica, Nicotiana tabacum and Thuja orientalis. They are explored at six different concentrations (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0%) against C. maculatus and compared to effects of distilled water which is used as a control. Toxicities of 3%(V/V) extracts of N. tabacum, N. rustica, A. indica and T. orientalis against C. maculatus were 100%, 86.11%, 80.56% and 72.22%, respectively. Maximum mortality was caused by N. tabacum and N. rustica (100%), followed by A. indica (82%), whereas minimum mortality was observed in T. orientalis (64%) at 2.5%. Several phytochemicals, alkaloids, saponins, diterphenes, phytosterol, flavonoids and phenols were identified in N. tabacum and N. rustica, while few were present in A. indica. Phytosterol was present in greatest abundance. Saponins were only detected in aqueous extracts of N. rustica and N. tabacum. Taken together, these results indicate the utility of N. tabacum, N. rustica and A. indica as potential botanicals to control pest beetle and cowpea weevil.

As a multi-beneficial amendment, biochar is very useful to be applied for improving soil health and crop productivity. Therefore, this study was carried out to assess the influence of wood biochar and mineral nitrogen (N), phosphorus (P) and potassium (K) fertilisers viz, [(control; 100% NPK (120:90:60 kg ha−1); 75% NPK + 5 tonne biochar; 50% NPK + 10 tonne biochar; 25% NPK + 15 tonne biochar and 20 tonne biochar ha−1)] on wheat yield and soil properties under different management practices [(raised bed (more than 30 cm above the ground) and flat-bed)]. Split plot two factors randomised completed block (RCB) design with three replications were used where management practices were placed to main plot, while treatments were assigned to subplots. Maximum spike length, grain per spike, 1000 grain weight, grain and biological yield were obtained with application of 75% NPK + 5 tonne biochar ha−1 under both raised and flat-bed, which were statistically at par to 50% NPK + 10 tonne biochar ha−1. The grain and biological yield observed at 75% NPK + 5 tonne biochar and 50% NPK + 10 tonne biochar ha−1 were significantly higher than that of 20 tonne biochar ha−1. However, maximum soil organic matter, extractable P and K contents with slight increases in soil pH and EC was observed at 20 tonne biochar ha−1. Moreover, almost all agronomic parameters were significantly better in raised bed compared to flat-bed sowing. Hence, the present study suggested that 75% NPK + 5 tonne biochar ha−1 is suitable for improving wheat yield and soil properties.

Globally, around 2000 plant species are used against pest control. The utilization of botanicals is considered the most economic and biodegradable methods for the control of stored grains pests. Therefore, the current study was carried out to investigate the repellency potential of five botanicals against Callosbruchus maculatus F. in Haripur, Pakistan. The concentrations of Azadirachta indica L., Nicotiana tabacum L., Melia azedarach L., Nicotiana rustica L., and Thuja orientalis L. were, i.e., 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0% in four replicates to establish contact effects. The data were recorded after 1, 2, 3, 6, 24, 48, 72, and 96 hours. The repellency effect of these plant species against C. maculatus were increased in both the time- and dose-dependent manner, and highest effect was observed at 72 h. In addition, the repellency effect was 91% for A. indica (class: V), 86% M. azedarach, 82%, N. tabacum (class: V), 79% N. rustica (class: IV), and 75% T. orientalis (class: IV) at 3% concentration against C. maculatus. Furthermore, following 96 hours’ exposure to treatment the sensitivity response of insects decreases as the time interval increases, i.e., 86% A. indica (class: V) was followed by 71% M. azedarach (class: IV), 65% N. tabacum (class: IV), 61% N. rustica (class: IV), and T. orientalis 57% (class: III) repellency at highest concentration of 3%. The current study concluded that A. indica and M. azedarach can be incorporated for the management of C. maculatus and these plant species might be helpful in the productions of new biopesticides.

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