The viruses are one of the most threatening factors for plants resulting in gigantic economic losses. These utilize host internal machinery for reproduction and can spread through biological and non-biological means. Among the most hazardous plant viruses, Tobacco mosaic virus (TMV) is the most ancient virus which causes massive economic losses to tobacco, pepper, cucumber and ornamental crops globally. The problem can be reduced by minimizing the vector population through application of pesticides. Opposite to obtained success in virus control, rapid utilization of synthetic chemicals is disastrous for our ecosystem. Therefore, alternative approaches such as natural derivatives should be explored for eco-friendly management of TMV. So, here we have tried to take into account various natural metabolites which can be effectively and potentially used against TMV. We further explained about the derivatives from animals, fungi, bacteria and actinomycetes which are useful against TMV. The review imbibes the recent research findings regarding exploration of natural derivatives for management of TMV and concludes through highlighting the future prospects via hoping that future pesticides will be safer for human being and our planet.

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Management of Tobacco Mosaic Virus through Natural Metabolites

We present the first comprehensive inventory of the mites of Pakistan, based on data from published books and papers. The fauna as presently understood includes 126 families, 316 genera, and 1105 species. The best-documented genera are those that include pests of stored food (for example Acotyledon, 28 species), plant pests (Brevipalpus, 49 species; Tenuipalpus, 35 species), and beneficial predators (Euseius, 44 species; Neoseiulus, 37 species; Phytoseius, 36 species; Typhlodromus, 47 species). Some economically important families such as the Eriophyidae are almost completely unknown. Some of the Cryptostigmata have been studied, but other groups of soil mites are very poorly known. Other large groups such as the feather mites, water mites, Uropodina, and parasitic Astigmata and Prostigmata, have not been studied in a systematic way. An increase in knowledge of these groups would help an assessment of their economic importance, and would make a valuable contribution to the biogeography of the western section of the Oriental Region and the southern section of the Palaearctic Region.

/pdf/checklist-of-the-mites-of-pakistan-1yenon5t8p.pdf

Checklist of the mites of Pakistan.

The control of Spodoptera frugiperda, the key invasive pest of maize, is a serious concern due to its biology and the current global restriction on applying synthetic pesticides. Entomopathogenic fungi are considered to be a potential biological control strategy. The pathogenicity of 12 isolates of Beauveria bassiana in the immature stages and feeding efficacy of S. frugiperda were evaluated. The B. bassiana isolates QB-3.45, QB-3.46 and QB-3.428 caused the highest egg mortality rates of 87.3, 82.7 and 79.3%, respectively, when applied at a concentration of 1 × 108 conidia/mL and measured at 7 days post-treatment. Neonate mortality rates of 45.6 to 53.6% were observed with the same isolates. The B. bassiana isolates caused significant cumulative mortality rates ranging from 71.3 to 93.3% at 14 days post-treatment and reduced larval feeding efficacy from 69.4 to 77.8% at 48 h post-treatment. This study supports using the effective B. bassiana isolates as a biological control agent against S. frugiperda. The significant mortality of the eggs and neonatal larvae and the reduction in the feeding efficacy of the second instar larvae of the S. frugiperda that were treated with isolates of B. bassiana supports the application of entomopathogenic fungi as a biocontrol agent for the effective control of the S. frugiperda population.

/pdf/bioassays-of-beauveria-bassiana-isolates-against-the-fall-20u5arce.pdf

Bioassays of Beauveria bassiana Isolates against the Fall Armyworm, Spodoptera frugiperda

Maize is the most essential crop of China and its productivity has been recently endangered by the fall armyworm (FAW), Spodoptera frugiperda. Chemical pesticides are one of the most important strategies for managing FAW on a short-term basis. The seven synthetic insecticides including novel and conventional belong to four chemical group, spinetoram and spinosad (spinosyns), lambda-cyhalothrin, cypermethrin and bifenthrin (pyrethroids), abamectin (avermectins), broflinilide (diamides), were assessed for their efficiency in causing mortality to second instar S. frugiperda larvae at 24, 48 and 72 h post-treatment at five different serial concentrations (10 to 0.625 mg liter-1). The second instar S. frugiperda larvae were susceptible to the tested synthetic insecticides, however, the toxicity index of synthetic insecticides was estimated based on lethal concentration 50 (LC50), while, LC50 was calculated from the data of larval mortality. The broflanilide and abamectin proved to be the most toxic having the highest toxicity index of 100 and 78.29%, respectively, followed by cypermethrin and bifenthrin were showed toxicity index of 75.47 and 66.89%, respectively. The LC50 values were 0.606 and 0.774 mg liter-1 for broflanilide and abamectin, respectively, followed by cypermethrin and bifenthrin were showed LC50 values of 0.803 and 0.906 mg liter-1 at 72 h post-treatment. Rest of the other synthetic insecticides were showed moderate toxicity index of 42.11 to 62.09%, based on LC50 values were 1.439 to 0.976 mg liter-1 at 72 h post-treatment. The efficiency of synthetic insecticides was increased by increasing concentration level and exposure time. The screened synthetic insecticides among seven insecticides perhaps, provide basis for the development of novel insecticides for controlling S. frugiperda population after further research to evaluate and validate the laboratory results in the field.

/pdf/laboratory-efficacy-of-selected-synthetic-insecticides-3gp3u2dc.pdf

Laboratory efficacy of selected synthetic insecticides against second instar invasive fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae

Panonychus citri (citrus red mite) is a devastating pest of citrus orchards. The conventional chemical acaricides have been strongly forbidden for the management of agricultural insect pests in China. Therefore, we evaluated the susceptibility of adult and nymphs P. citri in laboratory against eight isolates of four fungal species, Akanthomyces lecanii, Metarhizium anisopliae, Beauveria bassiana and Aschersonia aleyrodis. Each citrus seedling having 40 adults (2-d-old) and nymphs (on separate plants) were sprayed with isolates at the concentration of 104 ~ 108 conidia mLˉ1 whereas controlled seedlings were sprayed with 0.02% Tween-80. After 9 days of fungal exposure, the four fungal isolates caused more than 50% mortality of mites, such as; 85.6%, 87.9%, 64.6% and 79.7% by A. lecanii (V3450), B. bassiana (BFZ0409), M. anisopliae (MFZ0706) and A. aleyrodis (AsG0910), respectively. The nymphal mites were less susceptible to applied fungi compared to adults. The LC50s of the tested isolates were determined by the fitted time-concentration-mortality relationships, which declined over days after spray. LT50s were decreased with a high concentration of isolates. After the 9-d inoculation, two isolates of B. bassiana (BFZ0409 and D1344) and one isolate of A. lecanii (V3450) were highly effective at the minimal dose of LC50 of 104 conidia mLˉ1 and are promising candidates to control mites, as compared to other tested fungal isolates.

Comparative pathogenicity of four entomopathogenic fungal species against nymphs and adults of citrus red mite on the citrus plantation

The present study was conducted to evaluate the susceptibility of Rhizoglyphus tritici against the comparative potential of ether extracts from Azadirachta indica, Eucalyptusrnsp., Citrullus colocynthis, Allium sativum, Nicotiana tabacum, Curcuma longa, Nerium indicum, Syzygiumrnaromaticum, Ocimum tenuiflorum and Cassia fistula. The whole trial was executed under laboratory conditions with five concentrations from T1-T5 (0.5%, 1%, 2%, 4% and 8%), and four exposure periods (7, 14, 21 and 28 days). The percentage inhibition of mite population was both time-dependent and concentration-dependent. All the plant extracts exhibited significant acaricidal potential for adult mite as compared to control. The significant population inhibition percentage trend was observed of C. longa 91%, 95.54%, 94.97% and 97.46% and S. aromaticum 88.06%, 92.17%, 95.27% and 96.67%rnfollowed by C. fistula 92.03%, 93.27%, 93.22% and 92.07% while least population inhibition percentage was observed of N. tabacum 84.70%, 85..08%, 90.70% and 93.14% after 7, 14, 21 and 28 days. The median lethal concentrations were also calculated for all extracts, and it was observed that S. aromaticum was highly toxic to mites at lowest concentration 0.128, 0.028, 0.006 and 0.005 followed by C. longa 0.071, 0.036, 0.027 and 0.016 while least toxicity was observed in C. colocynthis 0.047, 0.030, 0.009 and 0.009 against R. tritici, and lethal concentration (LC50) decreased with an increasing time of exposure of the R. tritici to the ether extract. It was concluded that acaricidal potential of plants is directly proportional to time exposure and during first and second week C. fistula and S. aromaticum followed C. longa but suddenly after two weeks acaricidal potential of S. aromaticum was boost up and it was concluded that C. fistula, S. aromaticum and C. longa proved to be more effective gainst stored grain mites as compared to the others plant extracts. Perhaps, this new study will provide the basis for further investigation in order to develop new and safer acaricides in field conditions.

https://www.entomoljournal.com/archives/2016/vol4issue1/PartI/4-1-35.pdf

Muhammad Hamid Bashir

Papers

Acaricidal potential of some botanicals against the stored grain mites, Rhizoglyphus tritici