Integrated Pest Management Systems can be used for Promoting Plant Development in Upland Cotton to Combat Reniform Nematode Losses.
Type of DegreeMaster's Thesis
Entomology and Plant Pathology
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Cotton (Gossypium hirsutum) growers of Alabama lost $8.2 million to the reniform nematode (Rotylenchulus reniformis) in 2014. The overall objective for this study was to develop a holistic integrated pest management strategy to enhance plant growth and reduce the yield losses due to R. reniformis in upland cotton by 1) evaluating commercially available growth hormones for the enhancement of cotton plant growth; 2) evaluating starter fertilizers for the enhancement of cotton plant growth; 3) evaluating two nematicides for efficacy on R. reniformis and; 4) combining the optimum growth hormones and starter fertilizers with the nematicide to determine the most efficient management strategy for R. reniformis on cotton. Greenhouse trials and microplot tests were evaluated and field trials were conducted in two Alabama locations in both R. reniformis infested soils and non-infested soils. Plant biomass of the entire plant was greater with the addition of Ascend™ (cytokinin 0.09%, gibberellic acid 0.03%, and indolebutyric acid 0.045%) as a seed treatment and as a seed treatment plus foliar spray compared to the untreated control. Ascend™ seed treatment plus foliar spray showed significantly lower nematode eggs per gram of root when compared to the control. Plant height and plant biomass were not increased by any starter fertilizer application in greenhouse trials. Nematode populations were greater (P < 0.05) than the untreated control with the addition of starter fertilizers. The nematicides Velum Total™ (Imidacloprid 22.2% and Fluopyram15.4%) and Vydate C-LV™ (Oxamyl 42%) were evaluated as seed treatments, in-furrow sprays, or foliar sprays. The Velum Total™ seed treatment and in-furrow spray treatments (P < 0.05) reduced R. reniformis eggs per gram of root when compared to the control. The best selected plant hormone, starter fertilizers and nematicides treatments from the greenhouse trials were then tested in microplot and field trials individually or as combination treatments. Vydate C-LV™ alone, Vydate C-LV™ + starter fertilizers, and Vydate C-LV™ + plant hormone + starter fertilizers supported increased plant biomass in the presence of R. reniformis as compared to the untreated control. Rotylenchulus reniformis eggs per gram of root were also lower in the Vydate C-LV™ + starter fertilizers as compared to the control. Trials in R. reniformis infested fields found that several treatment combinations supported a larger plant biomass compared to the control. The Velum Total™ and Vydate C-LV™ nematicides alone and in combination with the starter fertilizers and plant hormones reduced R. reniformis eggs per gram of root when compared to the untreated control. Increase in cotton yields in the R. reniformis infested fields with the addition of Velum Total™ + plant hormone + starter fertilizers (P < 0.05) were observed when compared to the control.