Nematicide effects on non-target nematodes in bermudagrass.

In turfgrass systems, nematicides are a valuable tool for managing plant-parasitic nematode populations, but few studies have examined nematicide effects on non-target nematodes. The study evaluated effects of turfgrass nematicide formulations of abamectin (Divanem SC), fluopyram (Indemnify), furfural (MultiGuard Protect EC), and fluensulfone (Nimitz Pro G) on non-target nematode populations in bermudagrass (Cynodon spp.). Nematicides were applied at labeled rates every four weeks as a summer treatment program from June 7, 2016 to August 30, 2016 and April 24, 2017 to July 18, 2017. Samples were collected before the initial treatment and 2 d, 14 d, 56 d, and 238 d after the final treatment in both years for nematode community analysis. Data from each nematicide treatment were compared to the untreated at each sample date using analysis of covariance with initial population counts serving as the covariate. Abamectin had moderate impact and fluopyram had substantial impact on the non-target nematodes. Furfural and fluensulfone had minimal impact on non-target nematodes. The results of this study suggest nematicides can impact non-target nematode densities in bermudagrass.In turfgrass systems, nematicides are a valuable tool for managing plant-parasitic nematode populations, but few studies have examined nematicide effects on non-target nematodes. The study evaluated effects of turfgrass nematicide formulations of abamectin (Divanem SC), fluopyram (Indemnify), furfural (MultiGuard Protect EC), and fluensulfone (Nimitz Pro G) on non-target nematode populations in bermudagrass (Cynodon spp.). Nematicides were applied at labeled rates every four weeks as a summer treatment program from June 7, 2016 to August 30, 2016 and April 24, 2017 to July 18, 2017. Samples were collected before the initial treatment and 2 d, 14 d, 56 d, and 238 d after the final treatment in both years for nematode community analysis. Data from each nematicide treatment were compared to the untreated at each sample date using analysis of covariance with initial population counts serving as the covariate. Abamectin had moderate impact and fluopyram had substantial impact on the non-target nematodes. Furfural and fluensulfone had minimal impact on non-target nematodes. The results of this study suggest nematicides can impact non-target nematode densities in bermudagrass.

Vertical Distribution of Pasteuria penetrans Parasitizing Meloidogyne incognita on Pittosporum tobira in Florida.

Pasteuria penetrans is considered as the primary agent responsible for soil suppressiveness to root-knot nematodes widely distributed in many agricultural fields. A preliminary survey on a Pittosporum tobira field where the grower had experienced a continuous decline in productivity caused by Meloidogyne incognita showed that the nematode was infected with Pasteuria penetrans. For effective control of the nematode, the bacterium and the host must coexist in the same root zone. The vertical distribution of Pasteuria penetrans and its relationship with the nematode host in the soil was investigated to identify (i) the vertical distribution of P. penetrans endospores in an irrigated P. tobira field and (ii) the relationship among P. penetrans endospore density, M. incognita J2 population density, and host plant root distribution over time. Soil bioassays revealed that endospore density was greater in the upper 18 cm of the top soil compared with the underlying depths. A correlation analysis showed that the endospore density was positively related to the J2 population density and host plant root distribution. Thus, the vertical distribution of P. penetrans was largely dependent on its nematode host which in turn was determined by the distribution of the host plant roots. The Pasteuria was predominant mostly in the upper layers of the soil where their nematode host and the plant host roots are abundant, a factor which may be a critical consideration when using P. penetrans as a nematode biological control agent.

Management of Root-knot Nematode (Meloidogyne incognita) on Pittosporum tobira Under Greenhouse, Field, and On-farm Conditions in Florida.

Root-knot nematodes are important pests of cut foliage crops in Florida. Currently, effective nematicides for control of these nematodes on cut foliage crops are lacking. Hence, research was conducted at the University of Florida to identify pesticides or biopesticides that could be used to manage these nematodes. The research comprised on-farm, field, and greenhouse trials. Nematicide treatments evaluated include commercial formulations of spirotetramat, furfural, and Purpureocillium lilacinum (=Paecilomyces lilacinus) strain 251. Treatment applications were made during the spring and fall seasons according to manufacturer's specifications. Efficacy was evaluated based on J2/100 cm3 of soil, J2/g of root, and crop yield (kg/plot). Unlike spirotetramat, which did not demonstrate any measurable effects on Meloidogyne incognita J2 in the soil, furfural and P. lilacinum were marginally effective in reducing the population density of M. incognita on Pittosporum tobira. However, nematode reduction did not affect yield significantly. Although furfural and P. lilacinum have some potential for management of M. incognita on cut foliage crops, their use as a lone management option would likely not provide the needed level of control. Early treatment application following infestation provided greater J2 suppression compared to late application, suggesting the need for growers to avoid infested fields.

Mitochondrial Haplotype-based Identification of Root-knot Nematodes (Meloidogyne spp.) on Cut Foliage Crops in Florida.

Florida accounts for more than 75% of the national cut foliage production. Unfortunately, root-knot nematodes (RKN) (Meloidogyne spp.) are a serious problem on these crops, rendering many farms unproductive. Currently, information on the Meloidogyne spp. occurring on most commonly cultivated cut foliage crops in Florida, and tools for their rapid identification are lacking. The objectives of this study were to (i) identify specific RKN infecting common ornamental cut foliage crops in Florida and (ii) evaluate the feasibility of using the mtDNA haplotype as a molecular diagnostic tool for rapid identification of large samples of RKN. A total of 200 Meloidogyne females were collected from cut foliage plant roots. Meloidogyne spp. were identified by PCR and RFLP of mitochondrial DNA. PCR and RFLP of mitochondrial DNA were effective in discriminating the Meloidogyne spp. present. Meloidogyne incognita is the most dominant RKN on cut foliage crops in Florida and must be a high target for making management decisions. Other Meloidogyne spp. identified include M. javanica, M. hapla, Meloidogyne sp. 1, and Meloidogyne sp. 2. The results for this study demonstrate the usefulness of the mtDNA haplotype-based designation as a valuable molecular tool for identification of Meloidogyne spp.