The Effects of ILeVO and VOTiVO on Root Penetration and Behavior of the Soybean Cyst Nematode, Heterodera glycines

Abstract

The objective of this study was to determine the effects of ILeVO (fluopyram) and VOTiVO (Bacillus firmus I-1582) seed treatments on Heterodera glycines second-stage juvenile (J2) root penetration and behavior. In a growth chamber experiment, roots of soybeans grown from treated or untreated seeds were inoculated with H. glycines J2s at soil depths of 2.5, 5, or 7.5 cm. ILeVO significantly reduced H. glycines root penetration compared with the untreated control, but only when J2s were inoculated at a soil depth of 2.5 cm, which was near the seed. Changes in nematode behavior were assessed by collecting 60-s videos of J2s after 2 h of exposure to exudates from treated seeds or radicles from treated seeds or from soil leachates in which treated seeds were planted. X- and y-coordinates of each of the 13 reference points were recorded every hour for 24 h. A custom program analyzed and transformed the coordinates into nematode motion parameters (speed and total change in curvature). ILeVO, but not VOTiVO, seed exudates significantly reduced J2 speed relative to the untreated control. Soil leachates from ILeVO or VOTiVO treatments had no consistent effect on H. glycines speed or total change in curvature compared with the untreated control. In another experiment, treated or untreated seeds were incubated in wells of 6-well tissue culture plates containing 11.5% Pluronic gel. Seeds were removed after 2 h, and approximately 50 J2s then were pipetted into each well. The plates were scanned every 60 min for 24 h, and the number of J2s in each well that moved a minimum distance of ≥300 µm was determined using another custom software program. ILeVO, but not VOTiVO, significantly reduced the movement of J2 populations relative to control wells in which no seeds were added. And wells that had seeds, treated or not, yielded significantly less J2 movement compared with the no-seed control. The results of these experiments indicate that ILeVO reduces activity on H. glycines J2s but may not affect nematodes beyond a limited area surrounding the treated seed.

From Old-Generation to Next-Generation Nematicides

“…In contrast, the hatching inhibition was irreversible when G. pallida cysts were exposed to concentrations of ≥50 µM for 32 days, probably due to the very long exposure period [74]. Exudates from soybean seeds treated with fluopyram also inhibited H. glycines J2 hatching [96,97].…”

“…Fluopyram was also used as a seed treatment for soybean to protect plants at the early developing stage from several nematodes (Heterodera glycines, M. incognita, Rotylenchulus reniformis, Pratylenchus spp., and Hoplolaimus spp.) and fungal pathogens (Fusarium virguliforme and Septoria glycines) [96,97,99,100,103], and for cotton against several nematodes (M. incognita, R. reniformis, and Hoplolaimus spp.) [104].…”

Effect of seed-applied fluopyram on Meloidogyne incognita infection and maturity in cotton and soybean

“…Seed-applied fluopyram suppressed J2 entry up to 5.0 cm in cotton and 2.5 cm in soybean. Fluopyram as a seed treatment was reported to suppress root penetration of the soybean cyst nematode, Heterodera glycines, up to 2.5 cm depth (Beeman et al, 2019). Seed-applied abamectin conferred protection at the 2.5-cm depth in cotton and soybean.…”

Microorganisms in the biological control of root-knot nematode: A metanalytical study

“…(Hu et al, 2019;Wesemael et al, 2011), Bacillus sp. (Beeman et al, 2019;Fernandes et al, 2013;Mazzuchelli et al, 2020;Zhao et al, 2018), Paecilomyce sp. (Eapen et al, 2005;Fernandes et al, 2014;Huang et al, 2020), Pseudomonas sp.…”