Muhammad Usman Ghazanfar

Naturally occurring entomopathogenic fungi infecting stored grain insect species in Punjab, Pakistan.

Abstract The occurrence of entomopathogenic fungi isolated from stored grain insect pests sampled from various geographical regions of Punjab, Pakistan, was investigated. In total, 25,720 insects from six different species were evaluated, and 195 isolates from 24 different fungal species were recovered. These included the Ascomycetes Beauveria bassiana sensu lato (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae) , Metarhizium anisopliae sensu lato (Metschnikoff) Sorokin (Hypocreales: Clavicipitaceae), Purpureocillium lilacinum (Thorn) Samson (Hypocreales: Ophiocordycipitaceae), and Lecanicillium attenuatum (Zare and W. Gams) (Hypocreales: Clavicipitaceae). The cadavers of red flour beetle Tribolium castaneum (Herbst.) (Coleoptera: Tenebrionidae) were significantly infected with the fungi followed by rice weevil Sitophilus oryzae (L.) (Coleoptera: Curculionidae), lesser grain borer Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), rusty grain beetle Cryptolestes ferrugineus (Stephens) (Coleoptera: Cucujidae), and cowpea weevil Callosobruchus maculatus (F.) (Coleoptera: Bruchidae); however, the least were recovered from khapra beetle Trogoderma granarium (Everts) (Coleoptera: Dermestidae). The geographical attributes (altitude, longitude, and latitude) greatly influenced the occurrence of entomopathogenic fungi with highest number of isolates found from >400 (m) altitude, 33°–34′ N latitude, and 73°–74′ E longitude. The findings of the current surveys clearly indicated that the entomopathogenic fungi are widely distributed in the insect cadavers, which may later be used in successful Integrated Pest Management programs.

Salicylic acid induced resistance in fruits to combat against postharvest pathogens: a review

Salicylic acid (SA), the plant hormone, is extensively involved in signalling pathway, primarily in defence to induced local and systemic resistances in fruits against postharvest pathogens. Exogenous application of SA on fruits at optimum or non-toxic concentration provided efficient control of decay caused by postharvest pathogens. SA has direct fungitoxic effect on pathogen growth. This review scrutinises the control of various postharvest diseases by the application of SA on different fruits. Furthermore, physiological mechanism involved in inducing resistance is also discussed. These findings are necessary for understanding the proper function of SA in harvested fruits. In future, there is a need to correlate the efficacy of SA with environmental conditions and should emphasise on molecular paths involved in signalling of induce resistance.

Alleviation of Abiotic Stress in Medicinal Plants by PGPR

The use of traditional medicine and medicinal plant is a normative practice for the maintenance of good health in most developing countries. Interest in the medicinal plants as a re-emerging health aid has been fuelled by the rising costs of prescription drugs in the maintenance of personal health and well-being in these countries. Medicinal plants face a number of biotic and abiotic environmental stresses that have a detrimental impact on growth and development. Among the various environmental stresses, some of the major abiotic stress factors are salinity, flooding, heavy metals, drought, cold, soil compaction, mechanical impedance and deficiency of nutrient. Under stress conditions, several plant physiological imbalances such as enhanced ethylene production and nutritional and hormonal imbalance may influence the growth and therapeutic traits of these plants. The use of conventional approaches to mitigate the abiotic stresses associated with medicinal plant did not bring much of success. Plant growth-promoting rhizobacteria (PGPR) are a group of soil beneficial bacteria that reside in the rhizosphere zone in association with the roots of different plants. Application of these bacteria to seeds or plants promotes plant growth or protects the plants from harmful effects of multifarious abiotic stress factor. In addition, these bacteria also characterised to protect their host plant from pathogenic microorganisms. The role of PGPR in relation to medicinal plants and their effect on growth and synthesis of therapeutic metabolites are still unclear under stress condition. This chapter explains the possible role of PGPR medicinal plant interactions, i.e. characteristics of medicinal plant, types of stress factor, plant response under stress, PGPR and their role in alleviating the stress in stressful conditions. This chapter envisaged the scope of studies published to date focusing on medicinal plant growth improvement, biologically active compound production and contribution of PGPR as an inducer of stress tolerance in these valuable plants.

Resistance to commonly used insecticides and phosphine fumigant in red palm weevil, Rhynchophorus ferrugineus (Olivier) in Pakistan

The red palm weevil Rhynchophorus ferrugineus (Olivier) is an important pest of date palms in many regions of the world. This paper reports the first survey of insecticide resistance in field populations of R. ferrugineus in Pakistan which were collected from seven date palm growing areas across Punjab and Khyber Pakhtunkhwa (KPK) provinces, Pakistan. The resistance was assessed by the diet incorporation method against the formulated commonly used chemical insecticides profenophos, imidacloprid, chlorpyrifos, cypermethrin, deltamethrin, spinosad, lambda-cyhalothrin and a fumigant phosphine. Elevated levels of resistance were recorded for cypermethrin, deltamethrin and phosphine after a long history of insecticide use in Pakistan. Resistance Ratios (RRs) were 63- to 79-fold for phosphine, 16- to 74-fold for cypermethrin, 13- to 58-fold for deltamethrin, 2.6- to 44-fold for profenophos, 3- to 24-fold for chlorpyrifos, 2- to 12-fold for lambda-cyhalothrin and 1- to 10-fold for spinosad compared to a susceptible control line. Resistant R. ferrugineus populations were mainly found in southern Punjab and to some extent in KPK. The populations from Bahawalpur, Vehari, Layyah and Dera Ghazi Khan were most resistant to chemical insecticides, while all populations exhibited high levels of resistance to phosphine. Of the eight agents tested, lower LC50 and LC90 values were recorded for spinosad and lambda-cyhalothrin. These results suggest that spinosad and lambda-cyhalothrin exhibit unique modes of action and given their better environmental profile, these two insecticides could be used in insecticide rotation or assist in phasing out the use of older insecticides. A changed pattern of both insecticides can be used sensibly be recommended without evidence of dose rates and frequencies used.

Virulence of entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae against red palm weevil, Rhynchophorus ferrugineus (Olivier): Virulence of fungi against red palm weevil

Nineteen different isolates of the entomopathogenic fungi Beauveria bassiana sensu lato (s.l.) and Metarhizium anisopliae s.l. (Ascomycota: Hypocreales), recovered from different soil samples (field crops, fruit orchards, vegetable fields and forests) and insect cadavers were tested against Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) at two different spore concentrations (1 × 107 and 1 × 108 conidia mL−1). Three isolates of B. bassiana and two of M. anisopliae gave >88 % larval and >75 % adult mortality of R. ferrugineus on their highest dose rate respectively. More sporulating cadavers (mycosis) resulted from a high dose rate compared to low dose on both life stages of R. ferrugineus. The current study confirmed the lethal action of B. bassiana and M. anisopliae isolates with mortality levels usually directly proportional to the conidial concentration. This study further confirmed that the isolates recovered from R. ferrugineus dead cadavers gave more mortality compared to the other sources. In the virulence assay two isolates of B. bassiana caused the highest percentage of both larval and adult mortality at all exposure intervals which suggest that they may be the most promising for use in sustainable management programs aimed at microbial control in date palm orchards.