Evaluation of Promising Sunflower Hybrids against Whitefly, Jassid and Capitulum borer

Pakistan imports edible oil to meet the national demands posing burden on national exchequer. She is trying to grow edible oil crops to overcome this expense. Area under Sunflower cultivation is continuously increasing in Pakistan. But, insect pest infestation is a major concern for the growers. There is a need to develop hybrids which are less susceptible to the insect pests. Present study was conducted to find the most less susceptible Sunflower hybrids. Promising sunflower hybrids were grown and relevant data were recorded. All the hybrids were found moderately resistant to Resistant. This response is subject to the availability of insect population in the field and environment plays an integral role in it. There is dire need to explore the potential further of these hybrids. Keywords: Sunflower, Hybrid, Screening, Whitefly, Jassid, capitulum borer

Changes in the Activities of Protective Enzymes Induced by Mepiquat Chloride (DPC) in Cotton to Defend Against Aphids

Background: Mepiquat chloride (DPC) enhances the resistance of cotton plants, and it is widely used as a growth regulator. DPC can stimulate photosynthesis, stabilize the structure of cotton leaves, and affect population reproduction and energy substances in cotton aphids, but interactions between DPC and cotton aphids remain unclear. In this study, we analyzed the physiological responses of cotton to DPC, and the toxicity of DPC toward cotton aphids, before and after feeding, to explore the DPC-induced defense mechanism against cotton aphids.Results: Measurements of protective enzyme activity in cotton showed that the soluble protein contents, peroxidase (POD) activity, and catalase (CAT) activity in cotton treated with different concentrations of DPC were higher than in the control. Superoxide dismutase (SOD) activity was higher than that of controls when the concentration of DPC was <0.1 g/L. Under aphid stress, POD activity of cotton treated with a low insect population density was significantly lower than that of controls, but the reverse was true for cotton treated with a high insect population density, and SOD activity was positively correlated with population density. The activities of detoxification enzymes in field and laboratory experiments showed that DPC promoted the specific activity of glutathione S-transferase (GST) in cotton aphids, while the specific activities of carboxylesterase and acetylcholinesterase were decreased.Conclusions: DPC enhanced the resistance of cotton by increasing the activity of protective enzymes. It also had a toxic effect on cotton aphids by increasing GST activity (the main DPC target) and lowering carboxylesterase and acetylcholinesterase activities. DPC increased the soluble protein content and SOD activity in cotton under aphid stress, and thereby enhanced tolerance to cotton aphids.

Modeling the effects of insecticides and external efforts on crop production

In this paper a nonlinear mathematical model is proposed and analyzed to understand the effects of insects, insecticides and external efforts on the agricultural crop productions. In the modeling process, we have assumed that crops grow logistically and decrease due to insects, which are wholly dependent on crops. Insecticides and external efforts are applied to control the insect population and enhance the crop production, respectively. The external efforts affect the intrinsic growth rate and carrying capacity of crop production. The feasibility of equilibria and their stability properties are discussed. We have identified the key parameters for the formulation of effective control strategies necessary to combat the insect population and increase the crop production using the approach of global sensitivity analysis. Numerical simulation is performed, which supports the analytical findings. It is shown that periodic oscillations arise through Hopf bifurcation as spraying rate of insecticides decreases. Our findings suggest that to gain the desired crop production, the rate of spraying and the quality of insecticides with proper use of external efforts are much important.

Temperature-Inducible Precision Guided Sterile Insect Technique

Releases of sterile males are the gold standard for many insect population control programs, and precise sex sorting to remove females prior to male releases is essential to the success of these operations. To advance traditional methods for scaling the generation of sterile males, we previously described a CRISPR-mediated precision-guided sterile insect technique (pgSIT), in which Cas9 and gRNA strains are genetically crossed to generate sterile males for release. While effective at generating F1 sterile males, pgSIT requires a genetic cross between the two parental strains which requires maintenance and sexing of two strains in a factory. Therefore, to further advance pgSIT by removing this crossing step, here we describe a next-generation Temperature-Inducible pgSIT (TI-pgSIT) technology and demonstrate its proof-of-concept in Drosophila melanogaster. Importantly, we were able to develop a true-breeding strain for TI-pgSIT that eliminates the requirement for sex sorting, a feature that may help further automate production at scale.

Simplified Phasmatodea population evolution algorithm for optimization

This work proposes a population evolution algorithm to deal with optimization problems based on the evolution characteristics of the Phasmatodea (stick insect) population, called the Phasmatodea population evolution algorithm (PPE). The PPE imitates the characteristics of convergent evolution, path dependence, population growth and competition in the evolution of the stick insect population in nature. The stick insect population tends to be the nearest dominant population in the evolution process, and the favorable evolution trend is more likely to be inherited by the next generation. This work combines population growth and competition models to achieve the above process. The implemented PPE has been tested and analyzed on 30 benchmark functions, and it has better performance than similar algorithms. This work uses several engineering optimization problems to test the algorithm and obtains good results.

The Dynamic of Insect Population Succession in Bird Poisoned by Pyrethroid Insecticides

Insecticide poisoning is one of the causes of death in wild birds. One of the insecticides that are often used is a pyrethroid. This study aims to determine the succession of insects in birds intoxicated by pyrethroid pesticide. This research was conducted in Dramaga campus, IPB University, Bogor, Indonesia. One quail (Coturnix coturnix japonica) was used as a control which was killed by manual neck dislocation, and one bird was treated orally treated with acute dose pyrethroid pesticide. Cadavers are placed in insect traps until they reach the skeletal stage of decomposition. Insects that enter the trap are collected every 6 hours for 24 hours, from the first day until the whole process of decomposition of the carrion reaches the skeletal stage. Then the insects are identified and counted. The results showed that the cadaver decomposition process in the treatment group took longer than the control group. In the control group, insects arrived for approximately 138 hours after the cadaver was placed, while the treatment group took approximately 324 hours. The types of insects in these two groups are relatively the same, namely flies (Order Diptera: Calliphoridae, Muscidae), cockroaches (Order Dictyoptera: Blattidae and Blaberidae) and Sarcophagidae), beetles (Order Coleoptera: Scarabidae), ants (Order Hymenoptera: Formicidae), earwigs (Order Dermaptera: Anisolabididae). Chrysomya megachepala was the dominant insect over the others and was always present from the early stages to post-decay in control and pyrethroid treatment.

Efficacy of Diatomaceous Earth and Vitellaria paradoxa Seed Oil in Storage of Cowpea under Ventilated and Non-ventilated Conditions

Storage of cowpea is highly constrained by insect pest infestation and losses caused by the cowpea weevil (Callosobruchus maculatus, F.) are high. Several methods have been used over the years to protect cowpea grains in storage, but the use of synthetic insecticides is very dominant and this has led to problems, such as the killing of non-target species, user hazards, harmful food residues, and evolution of resistance to chemicals. A search for alternative insect pest control methods which are relatively less harmful to the user and cheaper has become essential. The effectiveness of Diatomaceous earth (DE) and Vitellaria paradoxa seed oil (VPSO) for cowpea storage in polypropylene and jute bags under ventilated and non-ventilated storeroom conditions were investigated over three months period. Crude DE was applied at a dose rate of 1 g/kg of cowpea and a diluted concentration (10% v/v) of VPSO of 400 mL was mixed with 8 kg of cowpea. Live insect count, dead insect count, and germination percentage were assessed weekly while proximate analysis was carried out before and after storage. Mean live insect count increased in the ventilated store-room from 0.67±0.34 to 36.13±19.51insects/kg after 1 month and 3 months of storage respectively for untreated cowpea. Insect population in treated samples increased from 0.38±0.26to 24.78±23.33, and from 0.17±0.30 to 10.75±5.27 for DE and VPSO treated samples, respectively. In the non-ventilated storeroom, insect population increased from 0.33±0.26 to 36.96±19.09 for untreated cowpea, 0.17±0.20 to 33.08±30.07 for DE and 0.21±5.63 to 8.17±11.30 for VPSO treated cowpea. Based on insect count, both treatments were very effective in controlling cowpea weevil in the first two months of storage, however their potency reduced by the third month. The potency of DE deteriorated faster compared to VPSO however, DE treated cowpea was most effective for retaining seed germination in both ventilated and non-ventilated storerooms. Proximate analysis showed that cowpea treated with both treatments had similar nutrient composition after storage. Diatomaceous earth and Vitellaria paradoxa seed oil have potentials in their raw form for short term insect pest control in the storage of cowpea.