Hazrat Bilal

Isolation and efficacy of entomopathogenic fungus (Metarhizium anisopliae) for the control of Aedes albopictus Skuse larvae: suspected dengue vector in Pakistan.

OBJECTIVE To isolate the entomopathogenic fungus Metarhizium anisopliae (M. anisopliae) in the local environment, and evaluate its efficacy against the suspected dengue vector Aedes albopictus in Pakistan. METHODS According to the standard procedure, M. anisopliae was isolated from the dead mosquitoes which were collected from the field or dead after the collection. Bioassay was performed to determine its efficacy. RESULTS The results indicated that M. anisopliae had larvicidal effect with LC50 value 1.09×10(5) and LC90 value 1.90×10(13) while it took 45.41 h to kill 50% of tested population. CONCLUSIONS Taking long time to kill 50% population when compare with the synthetic insecticides, is the only drawback for the use of entomopathogenic fungus but these bio-pesticides are safe for the use.

Plants secondary metabolites for mosquito control

Dear Editor: Mosquito control lies in personal protection by using repellents and community education as the most economical method and application of eco-friendly larvicides for the control of mosquitoes. Synthetic insecticides are no doubt having quick actions but it received wide public concern for their adverse effects to the environment, like insecticide resistance[1], environmental pollution, toxic hazards to human and other non-target organisms. To mitigate these problems, a major trend has recently appeared, which includes the use of natural plant based products as insecticides which can provide an alternate to synthetic chemical insecticides. Plants have secondary metabolites which are required for interaction with the environment and confirmed to have biological activity and that can be helpful in protecting the plants from a diseases and insect pests. These compounds can be divided into different chemical groups like alkaloids, phenolic, terpenoids, rare amino acids, plant amines and glycosides. These compounds also play an important role as anti-nutritional components of food and animal feed with a number of phenolic compounds. These include cell wall phenolic components, lignifications of cells and polyphenols such as condensed tannins. Plant also used these volatile terpenoids in plant-plant interactions and serve as attractants for pollinators. Soluble secondary componds like cyanogenic glycosides isoflavonoids and alkaloids can also be toxic to animals. Plant terpenoids have been studied for their activities against a number of insects. Defense strategy of plant against insect pest and pathogens depends on the presence of volatile essential oils or monoterpenes. Due to presence of these compounds there are possibilities to search such plant extracts which can be effective against the mosquitoes. Many plants have been found to contain chemicals like limonin and nomilin which are helpful for the control of insects and are useful for field applications in mosquito control programmes such as Citrus cultivars[2-4] and Emblica officinalis, Ricinus communis, Acacia coucinna, Cinnamomum tejpata, Piper nigera, Coriandrum sativum, Olea vera, Linum usitatissimum, Syzygium aromaticum and Nigella sativa have shown better insecticidal effects against Aedes albopictus[5]. There are many other plant extracts which are being used against different stages of mosquitoes. Plant extracts and essential oils might be best alternative of synthetic insecticides for the control of disease vectors. However, further investigations are needed to determine the secondary metabolites of the effective plant extracts against mosquitoes for the development of new and safe insecticide. There is also need to develop such extraction methods which must be easy, understandable for the community and can be used at home level.

Trophic Relationships between Aphids and Their Primary Parasitoids

Abstract The present research was carried out to study the trophic relationship between aphids and their primary parasitoids in Pothwar, Pakistan during 2009–2010 in the districts of Rawalpindi, Attock, Chakwal, and Jhelum. Ten species of aphids were recorded from 17 host plants. The aphids were parasitized by 11 species of primary parasitoids. Five quantitative aphid-parasitoid food webs were constructed describing the trophic relationships between the community of aphids and their primary parasitoids.