Articles
EFFECTS OF THE NEMATICIDES ALDICARB AND FENAMIPHOS ON THE EGG HATCH, MOVEMENT, AND ROOT PENETRATION OF THE CARROT CYST NEMATODE, HETERODERA CAROTAE
Article number
532_24
Pages
189 – 194
Language
Abstract
The effect of the nematicides aldicarb and fenamiphos was investigated under laboratory conditions.
Two hundred cysts or 50 egg masses of Heterodera carotae were arranged on 2-cm diameter sieves provided with a 215 μm pore plastic net and contained in 3.5 cm diameter plastic Petri dishes.
Cysts and egg masses were incubated at 20 °C in exudates of carrot roots containing 0, 0.05, 0.5, 5, 25 or 50 μg/ml of either chemical in order to determine the chemical effect on egg hatch.
In other experiments, newly emerged second stage juveniles were maintained in solutions containing 0, 0.1, 0.5, 1 or 5 μg/ml of either nematicide, at 10 °C for 15 hours, and then poured on the top of 12 cm high and 3-cm diameter columns, containing sand wetted with the same nematicide concentrations to study the effect on the movement.
Treated nematodes were inoculated also in plastic pots containing two week old carrot seedlings to investigate the effect on root invasion.
Both columns and pots were left for three days in a growth chamber at 20 °C. Emergence of juveniles from cysts was suppressed by concentrations of 0.05–50 μg/ml fenamiphos and 5–50 μg/ml aldicarb.
Emergence of juveniles from egg masses was significantly reduced at 0.5 μg/ml and completely suppressed at higher concentrations of aldicarb.
Egg hatch from egg masses was not affected by fenamiphos at 0.5 μg/ml, but it was completely suppressed at higher concentrations.
When the chemicals were removed from treated cysts and egg masses, egg hatch resumed completely from cysts and egg masses treated with aldicarb and partially from those treated with fenamiphos.
Juvenile movement was suppressed by 0.1–5 μg/ml aldicarb or 5 μg/ml fenamiphos.
Carrot root invasion by juveniles was reduced by 0.1–5 μg/ml of both chemicals, with aldicarb giving better root protection than fenamiphos and completely inhibiting nematode root invasion at 1–5 μg/ml.
Two hundred cysts or 50 egg masses of Heterodera carotae were arranged on 2-cm diameter sieves provided with a 215 μm pore plastic net and contained in 3.5 cm diameter plastic Petri dishes.
Cysts and egg masses were incubated at 20 °C in exudates of carrot roots containing 0, 0.05, 0.5, 5, 25 or 50 μg/ml of either chemical in order to determine the chemical effect on egg hatch.
In other experiments, newly emerged second stage juveniles were maintained in solutions containing 0, 0.1, 0.5, 1 or 5 μg/ml of either nematicide, at 10 °C for 15 hours, and then poured on the top of 12 cm high and 3-cm diameter columns, containing sand wetted with the same nematicide concentrations to study the effect on the movement.
Treated nematodes were inoculated also in plastic pots containing two week old carrot seedlings to investigate the effect on root invasion.
Both columns and pots were left for three days in a growth chamber at 20 °C. Emergence of juveniles from cysts was suppressed by concentrations of 0.05–50 μg/ml fenamiphos and 5–50 μg/ml aldicarb.
Emergence of juveniles from egg masses was significantly reduced at 0.5 μg/ml and completely suppressed at higher concentrations of aldicarb.
Egg hatch from egg masses was not affected by fenamiphos at 0.5 μg/ml, but it was completely suppressed at higher concentrations.
When the chemicals were removed from treated cysts and egg masses, egg hatch resumed completely from cysts and egg masses treated with aldicarb and partially from those treated with fenamiphos.
Juvenile movement was suppressed by 0.1–5 μg/ml aldicarb or 5 μg/ml fenamiphos.
Carrot root invasion by juveniles was reduced by 0.1–5 μg/ml of both chemicals, with aldicarb giving better root protection than fenamiphos and completely inhibiting nematode root invasion at 1–5 μg/ml.
Authors
N. Greco, F. Elia
Keywords
Chemical control, Daucus carota, egg hatching, movement, root invasion
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