Phytotoxicity of the Systemic Insecticide Imidacloprid on Tomato and Cucumber in the Greenhouse

Abstract

<jats:p>Imidacloprid is a long-term systemic insecticide that is currently labeled under the trade name Marathon (imidacloprid, 1-[(6-chloro-3-pyridyl)methyl-4,5-dihydro-N-nitro-1-H-imidazol-2-amine, 1% granular on fritted clay, Bayer Corp., Kansas City, Mo.) for ornamental crops grown in greenhouses. The company that markets Marathon is seeking to expand its label to greenhouse-grown vegetable crops, although the rates they plan to label have not yet been divulged. Marathon was applied to cucumber (<jats:italic>Cucumis sativus</jats:italic> L. `Turbo') and tomato (<jats:italic>Lycopersicon esculentum</jats:italic> Mill. `Rutgers') at 0, 1/8, 1/4, 1/2, 3/4, and 1 tsp (0, 5, 10, 20, 30, and 40 mg a.i.) per 4.5-inch (550-mL) pot. Both species developed phytotoxicity symptoms of leaf chlorosis of the oldest leaves and distorted growth and marginal necrosis of newer leaves within 1 week after application. By the end of the experiment, even the lowest rate caused phytotoxicity symptoms. The symptoms were similar in appearance to Ca deficiency but cucumber foliar analysis revealed no difference in Ca, Zn, Fe, or Co across imidacloprid rates, however, Mg and B decreased whereas K and Mn increased linearly across imidacloprid rates. P, Cu, and Mo varied quadratically with 1/2 tsp (20 mg a.i.) per pot having the lowest P and Mo, and Cu increasing at the higher rates. These data indicate that imidacloprid can alter plant nutrition. The rates of imidacloprid applied here are not recommended for use on greenhouse-grown cucumber and tomato under similar growing conditions as in this study.</jats:p>

10.5937/ratpov50-4792 = Effect of seed treatments with neonicotinoids on maize inbred lines seed quality

“…These results are in accordance with the results of Mrđa et al (2009) on sunflower seed, although there are opposite results which indicate that imidacloprid had no effect on the germination of seeds of maize (Bittencourt et al 2000, Dan et al 2012. Increased percentage of abnormal seedlings can be explained by the fact that application of imidacloprid at particular concentrations can lead to disturbances in the metabolism, resulting in the appearance of abnormal seedlings (Ebel et al 2000).…”

Seedling growth of maize (Zea mays L.) inbred lines affected by seed treatment with pesticides

“…Seed treatments with Maxim XL 035-FS + Gaucho 600-FS and Maxim XL 035-FS + Cruiser 350-FS reduced root length of seedlings (126.750 mm and 125.250 mm, respectively). The reduction of root length of inbred line 21202 x 21101 NS treated with Maxim XL 035-FS + Gaucho 600-FS was in accordance to the results achieved on cucumber and reported by Ebel et al (2000), who noted that the use of imidacloprid reduced the growth of the whole plant, decreased the root system, and altered mineral nutrition. Conversely, imidacloprid has been evaluated as a seed treatment without any phytotoxicity or adverse effects on plant growth of wheat, barley, and forage brassicas (Pike et al, 1993;Wilde et al, 2001;Stevens et al, 2008).…”

Effects of Neonicotinoid Seed Treatments on Cotton Seedling Physiology, Nutrition, and Growth

“…However, this is not consistent with other studies. For example, different rates of imidacloprid affected nutrient content in cucumber [39] as well as an increase in cotton plant height, chlorophyll content, and nitrogen content of leaves with increases in imidacloprid seed treatment concentration [16,40]. It is important to note that the nutrients were only analyzed in plants in the fifth true leaf stage in our study and nutrient status at earlier seedling stages could have been impacted.…”