Biocontrol Science and Technology
Navon, A., Department of Entomology, Volcani Center, Bet Dagan 50250, Israel
Nagalakshmi, V.K., Department of Entomology, Volcani Center, Bet Dagan 50250, Israel
Levski, S., Department of Entomology, Volcani Center, Bet Dagan 50250, Israel
Salame, L., Department of Nematology ARO, Volcani Center, Bet Dagan 50250, Israel
Glazer, I., Department of Nematology ARO, Volcani Center, Bet Dagan 50250, Israel
An improved calcium alginate gel formulation was developed and tested as a carrier for entomopathogenic nematodes against Spodoptera littoralis and Helicoverpa armigera larvae. Mortality of 100% was caused in 4th instar larvae of the two insects by feeding them on 1000 infective juveniles (IJ) g-1 of Steinernema carpocapsae (ALL strain) in the gel for 24 h. Exposing 2nd to 5th instars of H. armigera and 3rd to 6th of S. littoralis to 500 IJ g-1 of S. carpocapsae (ALL strain) resulted in 70-100% larval mortality. Mature larvae were less susceptible to the nematodes. Mortality of larvae exposed to 500 IJ g-1 of S. carpocapsae (ALL strain) ranged from about 45-55% ar 4 h to 90-95% at 48 h. Fourth instar larvae fed for 24 h with 250 IJ g-1 of nematode strains in gel showed in S. littoralis ranges of susceptibility in the following descending order: S. feltiae (IS-7 strain) = S. carpocapsae (DT strain) = S. feltiae (IS-6 strain) > S. carpocapsae (Mexican strain) = S. carpocapsae (ALL strain) = Heterorhabditis bacteriophora (HP-88 strain) = H sp. (IS-5 strain) > S. riobravae (Texas strain); in H. armigera the rating was: S. feltiae (IS-7 strain) = H. bacteriophora (HP-88 strain) > S. carpocapsae (ALL strain) = S. feltiae (IS-6 strain) = Heterorhabditis sp. (IS-5 strain) > S. carpocapsae (Mexican strain) > S. riobravae (Texas strain). The number of nematodes per larval cadaver increased with mortality rates. In greenhouse tests at 28 ± 2°C and 90% relative humidity, gel discs containing 500 IJ g-1 of nematodes were pinned to leaves of potted plants of cotton (Gossypium hirsutum) (Acala SJ2) and the plants were offered to S. littoralis larvae. Larval mortality of 89 ± 12.7% was caused by S. feltiae (IS-7 strain) and most of the plant leaves were protected against the larvae by the nematodes. In the control, larval mortality was 3.3 ± 0.05% and the plants were almost completely defoliated. Possibilities of using the gel-nematode formulation to protect sheltered crops against insect pests are discussed.

Itamar's own PDF.

פותח על ידי קלירמאש פתרונות בע"מ -
הספר "אוצר וולקני"
אודות
תנאי שימוש
Effectiveness of entomopathogenic nematodes in an alginate gel formulation against lepidopterous pests
12
Navon, A., Department of Entomology, Volcani Center, Bet Dagan 50250, Israel
Nagalakshmi, V.K., Department of Entomology, Volcani Center, Bet Dagan 50250, Israel
Levski, S., Department of Entomology, Volcani Center, Bet Dagan 50250, Israel
Salame, L., Department of Nematology ARO, Volcani Center, Bet Dagan 50250, Israel
Glazer, I., Department of Nematology ARO, Volcani Center, Bet Dagan 50250, Israel
Effectiveness of entomopathogenic nematodes in an alginate gel formulation against lepidopterous pests
An improved calcium alginate gel formulation was developed and tested as a carrier for entomopathogenic nematodes against Spodoptera littoralis and Helicoverpa armigera larvae. Mortality of 100% was caused in 4th instar larvae of the two insects by feeding them on 1000 infective juveniles (IJ) g-1 of Steinernema carpocapsae (ALL strain) in the gel for 24 h. Exposing 2nd to 5th instars of H. armigera and 3rd to 6th of S. littoralis to 500 IJ g-1 of S. carpocapsae (ALL strain) resulted in 70-100% larval mortality. Mature larvae were less susceptible to the nematodes. Mortality of larvae exposed to 500 IJ g-1 of S. carpocapsae (ALL strain) ranged from about 45-55% ar 4 h to 90-95% at 48 h. Fourth instar larvae fed for 24 h with 250 IJ g-1 of nematode strains in gel showed in S. littoralis ranges of susceptibility in the following descending order: S. feltiae (IS-7 strain) = S. carpocapsae (DT strain) = S. feltiae (IS-6 strain) > S. carpocapsae (Mexican strain) = S. carpocapsae (ALL strain) = Heterorhabditis bacteriophora (HP-88 strain) = H sp. (IS-5 strain) > S. riobravae (Texas strain); in H. armigera the rating was: S. feltiae (IS-7 strain) = H. bacteriophora (HP-88 strain) > S. carpocapsae (ALL strain) = S. feltiae (IS-6 strain) = Heterorhabditis sp. (IS-5 strain) > S. carpocapsae (Mexican strain) > S. riobravae (Texas strain). The number of nematodes per larval cadaver increased with mortality rates. In greenhouse tests at 28 ± 2°C and 90% relative humidity, gel discs containing 500 IJ g-1 of nematodes were pinned to leaves of potted plants of cotton (Gossypium hirsutum) (Acala SJ2) and the plants were offered to S. littoralis larvae. Larval mortality of 89 ± 12.7% was caused by S. feltiae (IS-7 strain) and most of the plant leaves were protected against the larvae by the nematodes. In the control, larval mortality was 3.3 ± 0.05% and the plants were almost completely defoliated. Possibilities of using the gel-nematode formulation to protect sheltered crops against insect pests are discussed.
Scientific Publication