Studies on the effects of synthetic glycinoeclepin A analogs on hatching of Heterodera glycines
Date
1997
Authors
Thompson, Jacqueline Mae
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Tylka, Gregory L.
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Abstract
In vitro hatch assays were conducted to determine the effects of a range of concentrations of selected synthetic glycinoeclepin A analogs on the hatching of Heterodera glycines Ichinohe. Cysts were collected from greenhouse-grown soybean plants inoculated with an Iowa race 3 isolate of H. glycines. H. glycines eggs were collected, surface disinfested, and placed onto 25- or 30-μm-pore microsieves which were placed into trays containing a treatment solution. Treatment solutions consisted of 3 synthetic analogs of glycinoeclepin A at 21 concentrations from ranging 5x10⁻¹² μg/ml to 500 μg/ml, a neutral control solution (deionized water), and a positive control (3.0 mM ZnSO₄). Microsieves containing eggs were transferred to fresh treatment solutions every other day, and hatched juveniles were counted. After 22 or 26 days, unhatched eggs remaining on the microsieves were counted and cumulative percent hatch was calculated. Hatching was most consistently inhibited by the 50 μg/ml concentration of all three synthetic analogs tested. Hatching in 100 to 500 μg/ml concentrations was not different (P̲ ≥ 0.05) from hatch in 50 μg/ml. Hatching in low concentrations (5x10⁻¹² to 5x10⁻¹ μg/ml) was not different (P̲ ≥ 0.05) than water, except for that in 2-hydroxymethylenecyclopentanone, which stimulated egg hatch at 1, 2.5, and 5 μg/ml relative to hatch in water. Calculated IC₅₀ (inhibition concentration) values of the synthetic analogs ranged from 14.0 μg/ml to 20.3 μg/ml. No difference in embryo development due to incubation in treatment solutions was detected. Results show consistent inhibition of H. glycines hatching when incubated in high concentrations of all three synthetic analogs tested.
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