Effect of some commonly used pesticides on seed germination, biomass production and photosynthetic pigments in tomato (Lycopersicon esculentum)

Abstract

Pesticides are highly toxic substances. Their toxicity may not be absolutely specific to the target organisms but can adversely affect different processes in the non-target host plants. In the present study, the effect of over application of four commonly used pesticides (emamectin benzoate, alpha-cypermethrin, lambda-cyhalothrin and imidacloprid) was evaluated on the germination, seedling vigor and photosynthetic pigments in tomato. The obtained results revealed that seed germination was decreased by the pesticides and this effect was more prominent at early stages of exposure. All the tested pesticides reduced the growth of tomato when applied in higher concentration than the recommended dose, but at lower doses the pesticides had some stimulatory effects on growth as compared to the control. A similar effect of pesticides was observed on the photosynthetic pigments, i.e. a decrease in pigments concentrations was caused at higher doses but an increase was observed at lower doses of pesticides. The calculation of EC50 values for different parameters revealed the lowest EC50 values for emamectin (ranged as 51-181 mg/L) followed by alpha-cypermethrin (191.74-374.39), lambda-cyhalothrin (102.43-354.28) and imidacloprid (430.29-1979.66 mg/L). A comparison of the obtained EC50 values for different parameters of tomato with the recommended doses revealed that over application of these pesticides can be harmful to tomato crop. In a few cases these pesticides were found toxic even at the recommended doses. However, a field based study in this regard should be conducted to further verify these results.

Hydrogen Peroxide for Insect and Algae Control in a Lettuce Hydroponic Environment

“…On the other hand, the dry weight of the flowers, peduncles, leaves and roots of Gerbera jamesonii (Asteraceae) exposed to Spinosyn (concentrations of 1× and 4× more than that recommended) were not affected when the insecticide was applied to the seedlings (Spiers et al 2006). Shakir et al (2015) also observed that low concentrations of insecticides stimulated the germination of tomato seeds, while high doses acted as inhibitors. Thus, due to the complexity of factors potentially capable of interfering with the germination of lettuce seeds, we suggest that applications of insecticides to control insect pests in hydroponic systems should be avoided in the initial stages (such as seeds).…”

“…This justification also applies to the fact that this insecticide has retarded the growth of algae in the phenolic foam plates over time. The exposure time (immediately after sowing) may have potentiated its toxic effect, as observed by Shakir et al (2015) in tomato seeds. This demonstrates the seed sensitivity to insecticide exposure.…”

Effect of Mancozeb on Mustard (Brassica juncea L.): An In-vitro study

“…According to Anitha & Savitha (2013), Petit et al (2012) and Shakir et al (2016) chlorophyll content were also reduced after increasing the dose of Mancozeb fungicides. Majid et al (2014), Singh & Kaur (2016) and Parween et al (2016) reported oxidative stress caused by Mancozeb that affect overall plant growth as well as biochemical parameters especially chlorophyll content.…”

“…Petit et al (2012), Anitha & Savitha (2013) and Shakir et al (2016) were also reported that growth of plants was reduced after increasing the dose of Mancozeb fungicides. Results were in agreement with the work done by Windham & Windham (2004), Bensoltane et al (2006) and Mohammed & Alrajh (2014) who have reported that Mancozeb is a systemic fungicides which are based on sterol biosynthesis inhibitor are closely related to plant growth regulators the use of which at higher than labeled rates shorten the internodes which may lead to slow-shoot and root growth.…”

Response of African marigold (Tagetes erecta L.) to different concentrations of chlorpyrifos and microbial diversity in root rhizosphere

“…Our results are in close conformity with the parameter, such a morphology found to be increased at recommended dose level. However they said higher dose caused the toxic effect in tomato [35]. The presence of pesticide residue in soil and dificiecy of nutrient affects the uptake of micronutrient in plant, and ultimately it refelects the abnormality of plant growth parameters [36].…”