Pesticides: An alarming detrimental to health and environment

Pesticides are chemical substances of natural or synthetic origin that are used to eradicate pests and insects. These are indispensable in the agricultural processes for better crop production. Pesticide use aims to promote crop yield and protect the crops from diseases and damage. Pesticides must be handled carefully and disposed of appropriately because they are dangerous to people and other species by default. Environmental pollution occurs when pesticide contamination spreads away from the intended plants. Older pesticides such as lindane and dichlorodiphenyltrichloroethane (DDT) may remain in water and soil for a longer time. These accumulate in various parts of the food chain and cause damage to the ecosystem. Biological techniques in the management of pest control such as importation, augmentation, and conservation, and the accompanying procedures are more efficient, less expensive, and ecologically sound than other ways. This review mainly focuses on the consequences on the targeted and non-targeted organisms including the health and well-being of humans by the use of pesticides and their toxicity. The side effects that occur when a pesticide's LD50 exceeds the accepted limit through oral or skin penetration due to their binding to various receptors such as estrogen receptors, GABA, EGFR, and others. These pesticide classes include carbamates, pyrethroids, organochlorides, organophosphorus, and others. The current study seeks to highlight the urgent requirement for a novel agricultural concept that includes a major reduction in the use of chemical pesticides.

Horticultural oils: possible alternatives to chemical pesticides and insecticides

The farmers and agrochemical industries lack science-based knowledge about sustainable utilization of pesticides and insecticides. The investigation on rising use of chemical pesticides and insecticides has remarkable issue related to environment pollution, soil fertility, and human health; as such, nowadays, many people prefer natural alternatives over synthetic chemicals. Natural products, like horticultural oils, play a significant role for sustainable and safe integrated pest management, providing natural alternatives to chemical pesticides and insecticides. For several decades, both plant- and petroleum-based spray oils have been always used to control various pests, mites, and insects. Currently, these horticultural oils are used as a part of the integrated pest management, which utilizes secure and non-chemical pesticides rather than conventional pesticides. Horticultural oil refers to a complex mixture of hydro-carbons with traces of sulfur- and nitrogen-based compounds, extracted from plants. The key components of horticultural oils include paraffin and olefin. The horticultural oils are considered suitable since they are non-toxic to both plants and animals, are applied easily, have low risk properties, cost-effective, and play significant role in pest control, but show little effects on the beneficial insects. As a result, these attributes make horticultural oils to be considered as secure and effective alternative for chemical insecticides and pesticides for both commercial and domestic agriculture.

Production of trans-chrysanthemic acid, the monoterpene acid moiety of natural pyrethrin insecticides, in tomato fruit

The pyrethrum plant, Tanacetum cinerariifolium (Asteraceae) synthesizes a class of compounds called pyrethrins that have strong insecticidal properties but are safe to humans. Class I pyrethrins are esters of the monoterpenoid trans-chrysanthemic acid with one of three jasmonic-acid derived alcohols. We reconstructed the trans-chrysanthemic acid biosynthetic pathway in tomato fruits, which naturally produce high levels of the tetraterpene pigment lycopene, an isoprenoid which shares a common precursor, dimethylallyl diphosphate (DMAPP), with trans-chrysanthemic acid. trans-Chrysanthemic acid biosynthesis in tomato fruit was achieved by expressing the chrysanthemyl diphosphate synthase gene from T. cinerariifolium, encoding the enzyme that uses DMAPP to make trans-chrysanthemol, under the control of the fruit specific promoter PG, as well as an alcohol dehydrogenease (ADH) gene and aldehyde dehydrogenase (ALDH) gene from a wild tomato species, also under the control of the PG promoter. Tomato fruits expressing all three genes had a concentration of trans-chrysanthemic acid that was about 1.7-fold higher (by weight) than the levels of lycopene present in non-transgenic fruit, while the level of lycopene in the transgenic plants was reduced by 68%. Ninety seven percent of the diverted DMAPP was converted to trans-chrysanthemic acid, but 62% of this acid was further glycosylated. We conclude that the tomato fruit is an alternative platform for the biosynthesis of trans-chrysanthemic acid by metabolic engineering.