Abdul A. Buhroo

Mechanisms of plant defense against insect herbivores

Plants respond to herbivory through various morphological, biochemicals, and molecular mechanisms to counter/offset the effects of herbivore attack. The biochemical mechanisms of defense against the herbivores are wide-ranging, highly dynamic, and are mediated both by direct and indirect defenses. The defensive compounds are either produced constitutively or in response to plant damage, and affect feeding, growth, and survival of herbivores. In addition, plants also release volatile organic compounds that attract the natural enemies of the herbivores. These strategies either act independently or in conjunction with each other. However, our understanding of these defensive mechanisms is still limited. Induced resistance could be exploited as an important tool for the pest management to minimize the amounts of insecticides used for pest control. Host plant resistance to insects, particularly, induced resistance, can also be manipulated with the use of chemical elicitors of secondary metabolites, which confer resistance to insects. By understanding the mechanisms of induced resistance, we can predict the herbivores that are likely to be affected by induced responses. The elicitors of induced responses can be sprayed on crop plants to build up the natural defense system against damage caused by herbivores. The induced responses can also be engineered genetically, so that the defensive compounds are constitutively produced in plants against are challenged by the herbivory. Induced resistance can be exploited for developing crop cultivars, which readily produce the inducible response upon mild infestation, and can act as one of components of integrated pest management for sustainable crop production.

Nano-Biofungicides: Emerging Trend in Insect Pest Control

Application of pesticides, which encompasses insecticides, fungicides, herbicides, nematicides etc., being used for plant defence mechanisms, embarrasses pest organisms. Although, pesticides eliminate the problem of pests, the use of synthetic pesticides has resulted in unsustainable management of our soil resources. This can be explained as due to the development of resistance by the pest organisms on continuous exposure to the pesticides, thus posing a challenge which leads to development of new classes of pesticides. These pesticides, apart from targeting the pest organisms, causes undesirable effects to all matrices of the environment-viz, soil, water, air, biota etc., Hence, the need for the development of ecofriendly pesticides becomes immediate inevitability. However, there is no one single method for efficient command on insect pests. Among the various classes of pesticides, fungicides form a major group of domineering plant diseases of fungal origin, either by inhibiting the growth of the fungi or by complete biocidal activity. The significance of fungicides is due to the fact that fungal diseases stands first in crop thrashing world wide. Currently, apart from the existing synthetic fungicides in the market, biofungicides occupies an unique position in controlling target diseases of fungal origin. An advanced technology in the field of biopesticides is the employment of engineered nanomaterials. These nanomaterials are more reactive can conjugate with biofungicides forming covalent bonds. This unique property of nanomaterials are exploited to manage the plant-pest chain. Therefore, this manuscript focus on nanobiofungicides as a powerful alternative for eco-friendly management of insect pests, in the coming decade.

One-Pot Fabrication and Characterization of Silver Nanoparticles Using Solanum lycopersicum: An Eco-Friendly and Potent Control Tool against Rose Aphid, Macrosiphum rosae

The espousal of nanotechnology is a current come-up of the present revolution. As we know that the rose aphid, Macrosiphum rosae (Hemiptera: Aphididae), is a key pest on rose plant in Kashmir Valley, India, it exhibits a worldwide distribution. In the present study, we have synthesized biologically silver nanoparticles (Ag NPs) from Solanum lycopersicum and characterized them by UV-vis spectroscopy, TEM, and X-RD analysis. The experiment was performed by leaf dip method. Insecticidal solutions of different Ag NPs concentrations, namely, 200, 300, 400, and 500 ppm, were tested on M. rosae. For assessment purposes, leaves were treated with distilled water (used as control). Aphid mortality data revealed that the Ag NPs were effective at 500 ppm concentration. As the concentration and day’s treatment increased, the aphid mortality rate also increased. There were statistically significant differences in M. rosae mortality between concentrations by LSD at 5%. In wrapping up, the use of Ag NPs in pest control processes will be the most novel eco-friendly approach in the Kashmir Valley, India, in future.

Laboratory evaluation of entomopathogenic fungi as biological control agents against the bark beetle Pityogenes scitus Blandford (Coleoptera: Curculionidae) in Kashmir

Abstract The bark beetles (Coleoptera: Curculionidae) are widely recognised as one of the most damaging group of forest pests. Entomopathogenic fungi have shown great potential for the management of some bark beetle species. The efficacy of three entomopathogenic fungi, namely, Beauveria bassiana (Balsamo) Vuillemin, Metarhizium anisopliae sensu lato (Metchnikoff) Sorokin and Lecanicillium lecanii (Zimmerman) Zare and Gams was tested against the bark beetle Pityogenes scitus Blandford under the laboratory conditions. An insecticide – cyclone 505 EC, was also used as positive control in the experiment. Each fungal suspension contained 1.0×109 spores of fungi in 1 ml. In treated branches, B. bassiana and M. anisopliae caused higher percentage of mortalities, that is, 58.33% and 48%, respectively, after 10 days of treatment and 85% and 71%, respectively, after 20 days of treatment. In petri plate assay, B. bassiana, M. anisopliae and L. lecanii caused 100%, 100% and 73.33% of mortality respectively. The percentage of mortality caused by treated insecticide was 79.16%. The results obtained in the present study are promising; however, no recommendations concerning the potential use of these fungal pathogens in forest protection can be given, and further research studies are needed in this respect, especially under field conditions.