PARASITISM OF DIAPAUSING PINK BOLLWORM PECTINOPHORA GOSSYPIELLA (LEPIDOPTERA: GELECHIIDAE) LARVAE BY ENTOMOPATHOGENIC NEMATODES (NEMATODA: STEINERNEMATIDAE, HETERORHABDITIDAE)

Authors: Gouge, Dawn; Lee, Linda; Henneberry, Thomas

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Larvae of pink bollworm were exposed to insect parasitic nematodes. Insects were incubated in sand filled petri dishes for 6 or 9 d at 17C, then washed and incubated for a further 3 d at 27C. Steinernema riobravis infected larvae rapidly compared with Heterorhabditis bacteriophora, S. riobravis infected over a longer period of time. Larvae were then exposed to S. riobravis, S. carpocapsae, H. bacteriophora, or H. bacteriophora at a dosage of 50, 100, 200, or 400 IJs/larva. Insects were incubated in sand filled petri dishes for 7 d at 16C, then washed and incubated for a further 4 d at 27C. S. carpocapsae and H. bacteriophora infected larvae in higher numbers compared with H. bacteriophora and S. riobravis. A significant difference in infection levels occurred due to nematode dose. PBW infested bolls were exposed to S. riobravis, or H. bacteriophora. Infested bolls were incubated in boxes filled with soil. Boxes were incubated in a constant temperature incubator or outside, exposed to the ambient seasonal temperatures. Summer test involved a constant temperature incubation of 27C, and ambient field incubation of 17-35C at the soil surface and 21-27C 5 cm below the soil surface. The winter test involved a constant temperature incubation of 16C, and ambient field incubation of 15-21C at the soil surface and 13-18C 5 cm below the soil surface. After 5 d the bolls were crushed, insects removed and dissected. H. bacteriophora infected larvae in significantly higher numbers compared with S. riobravis.

Technical Abstract: Larvae of pink bollworm were exposed to insect parasitic nematodes. Insects were incubated in sand filled petri dishes for 6 or 9 d at 17C, then washed and incubated for a further 3 d at 27C. Steinernema riobravis infected larvae rapidly compared with Heterorhabditis bacteriophora, S. riobravis infected over a longer period of time. Larvae were then exposed to S. riobravis, S. carpocapsae, H. bacteriophora, or H. bacteriophora at a dosage of 50, 100, 200, or 400 IJs/larva. Insects were incubated in sand filled petri dishes for 7 d at 16C, then washed and incubated for a further 4 d at 27C. S. carpocapsae and H. bacteriophora infected larvae in higher numbers compared with H. bacteriophora and S. riobravis. A significant difference in infection levels occurred due to nematode dose. PBW infested bolls were exposed to S. riobravis, or H. bacteriophora. Infested bolls were incubated in boxes filled with soil. Boxes were incubated in a constant temperature incubator or outside, exposed to the ambient seasonal temperatures. Summer test involved a constant temperature incubation of 27C, and ambient field incubation of 17-35C at the soil surface and 21-27C 5 cm below the soil surface. The winter test involved a constant temperature incubation of 16C, and ambient field incubation of 15-21C at the soil surface and 13-18C 5 cm below the soil surface. After 5 d the bolls were crushed, insects removed and dissected. H. bacteriophora infected larvae in significantly higher numbers compared with S. riobravis.