The effect of an abamectin formulation (Vertimec© EC) was tested against the cyst nematodes Globodera pallida, Heterodera carotae and Heterodera schachtii in an in vitro hatching test. Abamectin is a mixture of macrocyclic lactones (abamectin B1a and B1b) produced by the actinomycete Streptomyces avermitilis. Cysts of the nematodes were subjected to different concentrations of an aqueous solution of the abamectin formulation (0, 1.125, 2.25, 4.5, 9.0, 18.0 and 36 ?g/mL) for different exposure times. Cysts were extracted from soil samples by the Fenwick can. Batches of 50 cysts of similar size were set up and arranged according to a complete randomized block design. Each treatment was replicated three times. Untreated cysts were used as controls. Carrot root leachate, 0.3 mM zinc chloride and 0.6 mM sodium metavanadate aqueous solutions were used as natural and artificial hatching agents for H. carotae, H. Schachtii and G. pallida, respectively. Three mL of the hatching agents were added to each batch of cysts which were incubated at 20 + 2 °C in a growth cabinet. Emerged juveniles were counted weekly. At the end of the hatching test cysts were crushed and unhatched eggs and juveniles counted. Juveniles emerging weekly were expressed as cumulative percentages of the total egg content of the cysts (hatched + unhatched). The mortality for each treatment was calculated from percentage hatch considering the natural death in the control by the Schneider Orellis' formula. Data of percentage mortality were subjected to probit analysis to estimate values of lethal doses (LD), that is abamectin dose required for 50, 60, 70, 80, 90 and 99.9% egg mortality at each exposure time. Nematode mortality increase with the increase of abamectin concentration or at the same concentration increasing the exposure time. Abamectin LD50 of 9.9, 13.2 and 796.0 ?g/mL were calculated for an exposure time of 24 hours for H. carotae, G. pallida and H. schachtii, respectively. At 384 hours exposure DL50 decreased at 3.6, 2.9 and 17.6 ?g/mL for the same nematode species.
In vitro effect of abamectin concentrations and exposure times on the survival of cyst nematodes
SASANELLI N;FRANCHI M
2018
Abstract
The effect of an abamectin formulation (Vertimec© EC) was tested against the cyst nematodes Globodera pallida, Heterodera carotae and Heterodera schachtii in an in vitro hatching test. Abamectin is a mixture of macrocyclic lactones (abamectin B1a and B1b) produced by the actinomycete Streptomyces avermitilis. Cysts of the nematodes were subjected to different concentrations of an aqueous solution of the abamectin formulation (0, 1.125, 2.25, 4.5, 9.0, 18.0 and 36 ?g/mL) for different exposure times. Cysts were extracted from soil samples by the Fenwick can. Batches of 50 cysts of similar size were set up and arranged according to a complete randomized block design. Each treatment was replicated three times. Untreated cysts were used as controls. Carrot root leachate, 0.3 mM zinc chloride and 0.6 mM sodium metavanadate aqueous solutions were used as natural and artificial hatching agents for H. carotae, H. Schachtii and G. pallida, respectively. Three mL of the hatching agents were added to each batch of cysts which were incubated at 20 + 2 °C in a growth cabinet. Emerged juveniles were counted weekly. At the end of the hatching test cysts were crushed and unhatched eggs and juveniles counted. Juveniles emerging weekly were expressed as cumulative percentages of the total egg content of the cysts (hatched + unhatched). The mortality for each treatment was calculated from percentage hatch considering the natural death in the control by the Schneider Orellis' formula. Data of percentage mortality were subjected to probit analysis to estimate values of lethal doses (LD), that is abamectin dose required for 50, 60, 70, 80, 90 and 99.9% egg mortality at each exposure time. Nematode mortality increase with the increase of abamectin concentration or at the same concentration increasing the exposure time. Abamectin LD50 of 9.9, 13.2 and 796.0 ?g/mL were calculated for an exposure time of 24 hours for H. carotae, G. pallida and H. schachtii, respectively. At 384 hours exposure DL50 decreased at 3.6, 2.9 and 17.6 ?g/mL for the same nematode species.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
