Show simple item record

dc.contributor.advisorStarr, James L.en_US
dc.creatorFaske, Travis Ryanen_US
dc.date.accessioned2010-01-15T00:15:21Zen_US
dc.date.accessioned2010-01-16T02:15:41Z
dc.date.available2010-01-15T00:15:21Zen_US
dc.date.available2010-01-16T02:15:41Z
dc.date.created2006-08en_US
dc.date.issued2009-06-02en_US
dc.identifier.urihttp://hdl.handle.net/1969.1/ETD-TAMU-1842
dc.description.abstractAbamectin is a blend of B1a and B1b avermectins that is being used as a seed treatment to control plant-parasitic nematodes on cotton. Data on the toxicity of abamectin and its effectiveness as a seed treatment to control Meloidogyne incognita or Rotylenchulus reniformis on cotton are lacking. The toxicity of abamectin was based on an assay of nematode mobility, LD50 values of 1.56 µg/ml and 32.9 µg/ml were calculated based on 2 hr exposure for M. incognita and R. reniformis, respectively. There was no recovery of either nematode after exposure for 1 hr to its LD50 concentration. Sublethal concentrations greater than 0.39 µg/ml for M. incognita and 8.2 µg/ml for R. reniformis reduced (P = 0.05) infectivity on tomato. In field trials, suppression (P = 0.05) of M. incognita was observed 32 DAP by abamectin seed treatment whereas no suppression of R. reniformis was observed. No suppression of M. incognita was perceived by abamectin seed treatment in microplots. Suppression of M. incognita was observed in microplots by harpinEA and harpingαβ as a seed treatment and foliar spray, respectively. Seed cotton yields were variable for abamectin-treated seed, but numerically positive for harpin-treated cotton. Initial gall formation on developing taproots was suppressed (P = 0.001), and penetration of 5-cm long taproots by M. incognita and R. reniformis was numerically suppressed by abamectin-treated compared to non-treated seed, but infection increased with root development. Using an assay of nematode mobility, the proportion of dead second-stage juveniles (J2) was higher (P = 0.05) following exposure to an excised radicle from abamectin-treated seed than non-treated seed, but lower (P = 0.05) than J2 exposed to the abamectin-treated seed coat. Thus a higher concentration of abamectin remained on the seed coat than emerging radicle. The concentration of abamectin transferred from the seed coat to the developing roots was limited, which contributed to the variability in suppression of plant-parasitic nematodes on cotton.en_US
dc.format.mediumelectronicen_US
dc.format.mimetypeapplication/pdfen_US
dc.language.isoen_USen_US
dc.subjectabamectinen_US
dc.subjectAvictaen_US
dc.subjectMeloidogyne incognitaen_US
dc.subjectroot-knot nematodeen_US
dc.subjectRotylenchulus reniformisen_US
dc.subjectreniform nematodeen_US
dc.subjectcottonen_US
dc.titleEfficacy of abamectin as a seed treatment for control of Meloidogyne incognita and Rotylenchulus reniformis on cottonen_US
dc.typeBooken
dc.typeThesisen
thesis.degree.departmentPlant Pathology and Microbiologyen_US
thesis.degree.disciplinePlant Pathologyen_US
thesis.degree.grantorTexas A&M Universityen_US
thesis.degree.nameDoctor of Philosophyen_US
thesis.degree.levelDoctoralen_US
dc.contributor.committeeMemberIsakeit, Thomasen_US
dc.contributor.committeeMemberKolomiets, Michaelen_US
dc.contributor.committeeMemberPike, Leonarden_US
dc.type.genreElectronic Dissertationen_US
dc.type.materialtexten_US
dc.format.digitalOriginborn digitalen_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record