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Meloidogyne incognita- and Rotylenchulus reniformis-resistant new cotton cultivars have recently become available, giving growers a new option in nematode management. The objectives of this study were: (i) to determine the yield potential of the new cultivars PHY 360 W3FE (M. incognita-resistant) and PHY 332 W3FE (R. reniformis-resistant) in nematode-infested fields and (ii) to evaluate the effects of combining the nematicides Reklemel (fluazaindolizine), Vydate C-LV (oxamyl), and the seed treatment BIOST Nematicide 100 (heat killed Burkholderia rinojenses and its non-living spent fermentation media) with resistant cotton cultivars on nematode population levels and lint yield. Field experiments in 2020 and 2021 indicated M. incognita population levels were 73% lower on PHY 360 W3FE (R) and 80% lower for R. reniformis on the PHY 332 W3FE (R) at 40 days after planting. Nematode eggs per gram of root were further reduced an average of 86% after the addition of Reklemel and Vydate C-LV when averaging both cultivars over the two years. Tests with BIOST Nematicide 100 + Reklemel + Vydate C-LV (0.56 + 2.5 L/ha) in both M. incognita and R. reniformis fields produced higher lint yields. Overall, planting PHY 360 W3FE (R) and PHY 332 W3FE (R) improved yields an average of 364 kg/ha while limiting nematode population increases. The addition of the nematicides further increased yields 152 kg/ha of the nematode-resistant cultivars.

Plant parasitic nematodes are major pests on upland cotton worldwide and in the United States. The reniform nematode, Rotylenchulus reniformis and the southern root-knot nematode Meloidogyne incognita are some of the most damaging nematodes on cotton in the United States. Current management strategies focus on reducing nematode populations with nematicides. The objective of this research was to integrate additional fertilizer and nematicide combinations into current practices to establish economical nematode management strategies while promoting cotton yield and profit. Microplot and field trials were run to evaluate fertilizer and nematicide combinations applied at the pinhead square (PHS) and first bloom (FB) plant growth stages to reduce nematode population density and promote plant growth and yield. Cost efficiency was evaluated based on profit from lint yields and chemical input costs. Data combined from 2019 and 2020 suggested a nematicide seed treatment (ST) ST + (NH4)2SO4 + Vydate® C-LV + Max-In® Sulfur was the most effective in increasing seed cotton yields in the R. reniformis microplot trials. In R. reniformis field trials, a nematicide ST + (NH4)2SO4 + Vydate® C-LV at PHS supported the largest lint yield and profit per hectare at $1176. In M. incognita field trials, a nematicide ST + 28-0-0-5 + Vydate® C-LV + Max-In® Sulfur at PHS and FB supported the largest lint yields and profit per hectare at $784. These results suggest that combinations utilizing fertilizers and nematicides applied together across the season in addition to current fertility management show potential to promote yield and profit in R. reniformis and M. incognita infested cotton fields.

Plant parasitic nematodes (PPN) are microscopic soil herbivores that cause damage to many economic crops. For the last century, it has been proposed that chemotaxis is the primary means by which PPN locate host plant roots. The identities and modes of action of chemoattractants that deliver host-specific messages to PPN, however, are still elusive. In this study, a unique multidimensional agar-based motility assay was developed to assess the impacts of root exudates on the short-range motility and orientation of PPN. Three PPN (Rotylenchulus reniformis, Meloidogyne incognita and Heterodera glycines) and root exudates from their respective host and non-host plants (cotton, soybean, and peanut) were used to validate the assay. As predicted, R. reniformis and M. incognita were attracted to root exudates of cotton and soybean (hosts), but not to the exudates of peanut (non-host). Likewise, H. glycines was attracted to soybean (host) root exudates. These results underpinned the intrinsic roles of root exudates in conveying the host specificity of PPN. In particular, PPN selectively identified and targeted to hydrophilic, but not hydrophobic, fractions of root exudates, indicating that groundwater should be an effective matrix for chemotaxis associated with PPN and their host plant interactions.

Cotton (Gossypium spp.) is attacked by parasitic nematodes including the reniform nematode (Rotylenchulus reniformis Linford and Oliveira). Options for management of reniform nematode are limited. No cultivars of upland cotton (G. hirsutum L.) have genetic resistance. Our objectives were to evaluate the USDA G. hirsutum collection for reaction to parasitism by R. reniformis, and determine the value of measurement of eggs (reproduction) or vermiform stages (nematode survival) as an indicator of nematode resistance. In groups of 50, accessions were evaluated in the greenhouse, using single plants in four replicates. Accessions were planted in sterile soil and inoclated with a mixture of R. reniformis isolates. After 60 d, soil populations of vermiform nematodes were determined, and eggs were extracted from the root system and counted. Paymaster 'PM 1218' was included as a check in every experiment. Out of 1973 accessions with at least one replication, none showed high levels of resistance. Seven accessions had lower population development than PM 1218 after repeated evaluations. Results indicated egg counts and vermiform counts were correlated, but not closely. Egg counts were higher and more variable than vermiform counts. While some accessions showed levels of resistance that might be useful in cotton improvement, evaluation remains difficult and introgression of genes for reniform nematode resistance remains a long-term breeding objective.

Objective. Solid organ transplant recipients are at increased risk for invasive pneumococcal disease. The American Academy of Pediatrics recommends immunization with sequential pneumococcal vaccines for this group; however, data are lacking. Accordingly, this study was designed to evaluate the safety and immunogenicity of the recommended regimen. Methods. Pediatric solid organ transplant recipients (n = 25) between 2 and 18 years of age who had not previously received 7-valent conjugate pneumococcal vaccine (PCV7) were enrolled. These patients received 2 doses of the PCV7 and a single dose of the 23-valent polysaccharide pneumococcal vaccine (23V). Each vaccine dose was given 2 months apart. Healthy age-matched controls (n = 23) were enrolled for comparison. Controls received a single dose of PCV7 followed 2 months later by a single dose of 23V. Antibody concentrations to serotypes 1, 4, 5, 6B, 9V, 14, 18C, 19F, and 23F were measured by enzyme-linked immunosorbent assay prevaccination, 2 months after each vaccine dose and 5 to 7 months after 23V. Local and systemic reactions to each vaccine dose were recorded. Results. Systemic and injection-site reactions were comparable between the 2 groups. Significant rises in serotype-specific pneumococcal antibody geometric mean concentrations from prevaccination levels were observed in both groups; however, final antibody responses to serotypes 1, 4, 9V, 14, 18C, 19F, and 23F were significantly lower in solid organ transplant recipients compared with the control group. Antibody concentrations did not increase significantly among solid organ transplant patients after the second dose of PCV7. No additional increase in PCV7-associated serotype-specific antibody levels was observed after the 23V dose in both groups. Heart transplant recipients had lower antibody responses compared with liver transplant recipients. Conclusions. Although the pneumococcal vaccine regimen was safe and immunogenic among pediatric solid organ transplant recipients, the patients did not seem to benefit from the second dose of PCV7 or from the 23V dose given 2 months later. Additional studies are needed to determine the number of PCV7 doses and the interval between PCV7 and 23V to induce optimal responses. Pediatrics 2005;116:160-167; solid organ transplant recipient, invasive pneumococcal disease, conjugate pneumococcal vaccine, vaccine response. ABBREVIATIONS. AAP, American Academy of Pediatrics; PCV7, 7-valent conjugate pneumococcal vaccine; 23V, 23-valent polysaccharide pneumococcal vaccine; PTLD, posttransplant lymphoproliferative disease; GMC, geometric mean antibody concentration., Solid organ transplant recipients are at increased risk of bacterial infections including invasive pneumococcal infections. (1-4) This has also been shown in pediatric solid organ transplant recipients, (5,6) who (like [...]