Essential oils (EOs) have been largely investigated for their biocidal activity on root-knot nematodes, Meloidogyne species, the most economically relevant group of phytoparasitic nematodes. Adversely, experimental activity on the effect of EOs on cyst-forming nematode species is very poor, though sustainable management of these nematode species should need new control tools alternative to chemicals, such as EOs-based formulates. EOs of Eugenia caryophyllata (L.) Merr. & L.M. Perry and Schinus molle L. are reported for a wide spectre of biological activities, among which also a biological activity against plant insect pests and fungal pathogens. The major component of the EO of E. caryophyllata is usually considered to be eugenol, with ?-caryophyllene and lower amounts of other components such as benzyl alcohol. The major constituents in S. molle EO were ?-phellandrene and ?-phellandrene, with variable amounts of ?-pinene, p-cymene and ?-pinene. An experimental activity was carried out to assess the in vitro effect of treatments with EOs on egg hatch of different cyst nematodes. Results of a hatching test with cysts of the potato and carrot cyst nematodes, Globodera rostochiensis and Heterodera carotae, respectively, treated with EOs of E. caryophyllata and S. molle are reported in this work. Batches of 100 cysts of each nematode species were exposed to 125, 250 and 500 ?l L-1 solutions of each EO for 12, 24 and 48 hours. There were 4 replications for each concentration x exposure time. Non-treated cysts were used as control. After treatments, hatching test of G. rostochiensis and H. carotae continued over 7 weeks in sodium metavanadate (0.6 mM) or zinc chloride (10 mM) solutions, respectively, counting emerged juveniles at weekly intervals. At the end of the experiment, unhatched eggs were determined and final cumulative percentage hatch was calculated. The EO of E. caryophyllata significantly reduced hatch of eggs of G. rostochiensis only after a 24 or 48 hour exposure to the highest concentration, whereas cyst treatment with the 125 ?l L-1 solution resulted in a significant increase of hatched eggs compared to the non-treated control. Adversely, all treatments with the same EO significantly reduced the percentage hatch of H. carotae eggs, with the exception of the 12 hour exposure to the 125 ?l L-1 solution. Compared to non-treated cysts, all treatments with the EO of S. molle did not significantly affect the hatch of G. rostochiensis, whereas significantly reduced the percentage hatch of H. carotae.
Effect of essential oils on the hatch of eggs of cyst-forming phytoparasitic nematodes
Laquale S;Sasanelli N;D'Addabbo T
2015
Abstract
Essential oils (EOs) have been largely investigated for their biocidal activity on root-knot nematodes, Meloidogyne species, the most economically relevant group of phytoparasitic nematodes. Adversely, experimental activity on the effect of EOs on cyst-forming nematode species is very poor, though sustainable management of these nematode species should need new control tools alternative to chemicals, such as EOs-based formulates. EOs of Eugenia caryophyllata (L.) Merr. & L.M. Perry and Schinus molle L. are reported for a wide spectre of biological activities, among which also a biological activity against plant insect pests and fungal pathogens. The major component of the EO of E. caryophyllata is usually considered to be eugenol, with ?-caryophyllene and lower amounts of other components such as benzyl alcohol. The major constituents in S. molle EO were ?-phellandrene and ?-phellandrene, with variable amounts of ?-pinene, p-cymene and ?-pinene. An experimental activity was carried out to assess the in vitro effect of treatments with EOs on egg hatch of different cyst nematodes. Results of a hatching test with cysts of the potato and carrot cyst nematodes, Globodera rostochiensis and Heterodera carotae, respectively, treated with EOs of E. caryophyllata and S. molle are reported in this work. Batches of 100 cysts of each nematode species were exposed to 125, 250 and 500 ?l L-1 solutions of each EO for 12, 24 and 48 hours. There were 4 replications for each concentration x exposure time. Non-treated cysts were used as control. After treatments, hatching test of G. rostochiensis and H. carotae continued over 7 weeks in sodium metavanadate (0.6 mM) or zinc chloride (10 mM) solutions, respectively, counting emerged juveniles at weekly intervals. At the end of the experiment, unhatched eggs were determined and final cumulative percentage hatch was calculated. The EO of E. caryophyllata significantly reduced hatch of eggs of G. rostochiensis only after a 24 or 48 hour exposure to the highest concentration, whereas cyst treatment with the 125 ?l L-1 solution resulted in a significant increase of hatched eggs compared to the non-treated control. Adversely, all treatments with the same EO significantly reduced the percentage hatch of H. carotae eggs, with the exception of the 12 hour exposure to the 125 ?l L-1 solution. Compared to non-treated cysts, all treatments with the EO of S. molle did not significantly affect the hatch of G. rostochiensis, whereas significantly reduced the percentage hatch of H. carotae.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
