Growth suppression of legumes in pyriproxyfen stressed soils:<br>A comparative study

Abstract

Insecticides are commonly used to combat economically important insect pests in agriculture. These plantprotecting agents severely decline crop productivity by affecting different plant growth parameters. The assessment of phytotoxicity of insecticides are generally, confined to one plant species and broad studies concomitantly evaluating the insecticide effect on more than one crop specifically, the legume are scarce. Hence, this study was designed to assess the effect of technical grade insecticide, pyriproxyfen simultaneously on legumes like chickpea, pea, lentil and greengram. Pyriproxyfen showed the highest toxicity to root and shoot dry biomass, leghaemoglobin, chlorophyll content and seed protein in chickpea, nodule numbers in pea, shoot nitrogen and root phosphorus in greengram, and nodule biomass, root nitrogen, root phosphorus, shoot phosphorus and seed yield in lentil. For instance, pyriproxyfen decreased the number of nodules (percent decline over controls) in each legume in an order: pea (44) > greengram (14) > chickpea (5) = lentil (5). Similarly, pyriproxyfen mediated percent decline in leghaemoglobin occurred in the order like: chickpea (69) > lentil (25) > pea (18) > greengram (12). Generally, pyriproxyfen affected most adversely the growth of both chickpea and lentil. It is concluded that the extent of phyto-toxicity of insecticide and the type of plant organs affected might differ among plant species.

Fate of Pyriproxyfen in Soils and Plants

“…Indeed, while the 50% lethal concentration in 72 h (72 h LC 50 ) of pyriproxyfen equaled 672.29 µg/cm 2 , the 72 h LC 50 values of 4 -OH-Pyr, DPH-Pyr, POP, POPA, PYPA, and PYPAC against earthworms equaled 30.39, 10.25, 13.29, 24.33, >75.52, and >78.79 µg/cm 2 , respectively [30]. In the same way, Ahemad [53] studied the potential adverse effects of pyriproxyfen (98%) on different plants. The insecticide showed the highest toxicity on the root and shoot dry biomass, leghaemoglobin chlorophyll content and seed protein in chickpea (Cicer arietinum L.); the nodule numbers in pea (Pisum sativum); the shoot N and root P in greengram (Vigna radiata L. Wiclzeck); and the nodule biomass, root N, root P, shoot P and seed yield in lentil (Lens esculentus).…”

The Challenge of Combining High Yields with Environmentally Friendly Bioproducts: A Review on the Compatibility of Pesticides with Microbial Inoculants

“…The insecticides not only reduced nodule number and dry weight but also nitrogenase activity in nodules and plant biomass production. Ahemad [23] also reported several negative effects with the application of pyriproxifene, at the recommended dose of 1300 µg kg −1 soil, in chickpeas (Cicer arietinum L.), peas (Pisum sativum L.), mung beans (Vigna radiata L. Wiclzek), and lentils (Lens esculentus, = Lens culinaris Medik) grown in pots that remained in an open field. Although the plants had not been inoculated, inferring that nodulation was related to indigenous rhizobia, pyriproxifer resulted in a 44% decrease in nodule number in peas, 14% in mung beans, and 5% in chickpeas and lentils, resulting in decreases in nodule dry weight compared with the controls not treated with insecticide.…”

Comparative effect of different insecticides on the growth and yield of soybeans

“…https://doi.org/10.17221/77/2019-PPS green grams; and the nodule biomass, root nitrogen, root phosphorus, shoot phosphorus and seed yield in lentils (Ahemad 2014). Organophosphate insecticides also reduce the germination of annual grasses and annual forb species (Gange et al 1992).…”