Herbicide Efficacy of Spot Spraying Systems in Fallow and Postharvest in the Pacific Northwest Dryland Wheat Production Region.

Real-time spot spraying technology has the potential to reduce herbicide costs and slow herbicide resistance. However, few studies exist on the efficacy of this technology in the Pacific Northwest (PNW). This research compared the herbicide efficacy (reduction in weed density and cover) of WEED-IT and WeedSeeker spot spraying systems to uniform spraying in fallow and postharvest in 2019 and 2020.

Weed responses to fallow management in Pacific Northwest dryland cropping systems.

A two-year rotation of summer fallow (SF)/winter wheat (WW) is the most common cropping system in low precipitation areas of the U.S. Pacific Northwest (PNW).

Selected Pacific Northwest Rangeland and Weed Plants as Hosts of Pratylenchus neglectus and P. thornei.

Eighteen rangeland plants and 16 weed species were assayed in the greenhouse for efficiency as hosts of Pratylenchus neglectus and P. thornei. Hosting ability ratings were assigned using the ratio of final versus initial nematode density and by comparing the final nematode density to that of susceptible wheat controls.

Selected Pacific Northwest Crops as Hosts of Pratylenchus neglectus and P. thornei.

Thirty crop species and cultivars were assayed in the greenhouse for efficiency as hosts of Pratylenchus neglectus and P. thornei. Hosting ability ratings were assigned using the ratio of final versus initial nematode density and also by comparing the final nematode density to that of a susceptible wheat control.

Resistance and Tolerance of Landrace Wheat in Fields Infested with Pratylenchus neglectus and P. thornei.

Pratylenchus neglectus and P. thornei reduce wheat yields in the Pacific Northwest of the United States. Resistant landrace cultivars have been identified using controlled environments.

Spring Wheat Tolerance and Resistance to Heterodera avenae in the Pacific Northwest.

The cereal cyst nematode Heterodera avenae reduces wheat yields in the Pacific Northwest. Previous evaluations of cultivar resistance had been in controlled environments. Cultivar tolerance had not been evaluated.

Effects of Crop Rotations and Tillage on Pratylenchus spp. in the Semiarid Pacific Northwest United States.

There is interest in converting rainfed cropping systems in the Pacific Northwest from a 2-year rotation of winter wheat and cultivated fallow to direct-seed (no-till) systems that include chemical fallow, spring cereals, and food legume and brassica crops. Little information is available regarding effects of these changes on plant-parasitic nematodes. Eight cropping systems in a low-precipitation region (<330 mm) were compared over 9 years.

Influence of Semiarid Cropping Systems on Root Diseases and Inoculum Density of Soilborne Pathogens.

There is interest in converting the 2-year rotation of rainfed winter wheat with cultivated fallow in the Pacific Northwest of the United States into direct-seed (no-till) systems that include chemical fallow, spring cereals, and food-legume and brassica crops. Eight cropping systems in a low-precipitation region (<330 mm) were compared over 9 years to determine effects of changes on diseases. Fusarium crown rot was more prevalent in wheat following cultivated than chemical fallow, and Rhizoctonia root rot was more severe when winter wheat was rotated with chemical fallow than with no-till winter pea.

Influence of Nematicides and Fungicides on Spring Wheat in Fields Infested with Soilborne Pathogens.

A complex of fungal soilborne pathogens and plant-parasitic nematodes reduces wheat yields in the Pacific Northwest. On several other crops in nematode-infested soils, seed treatment with abamectin (Avicta) or Bacillus firmus (Votivo) or foliar application of spirotetramat (Movento) reduced root injury and improved yield. These products, along with fungicide seed treatments and aldicarb (Temik), were evaluated in 13 spring wheat trials over 3 years.

Geocenamus brevidens Associated with Reduced Yield of No-Till Annual Spring Wheat in Oregon.

Associations between stunt nematodes and yield of no-till annual spring wheat (Triticum aestivum) were examined at two eastern Oregon locations. Geocenamus brevidens was the only species detected at one location and was mixed with Tylenchorhynchus clarus at another location. Six cultivars were planted with or without application of aldicarb during 2001.

Suppression of Wheat Growth and Yield by Pratylenchus neglectus in the Pacific Northwest.

Many wheat (Triticum aestivum) fields planted annually in the Pacific Northwest are infested by high populations of the lesion nematode, Pratylenchus neglectus. Spring wheat cultivars varying in tolerance and resistance to P. neglectus were treated or not treated with aldicarb to examine relationships between the nematode and growth and yield of annual direct-seeded (no-till) wheat.

Pathogenicity of Fungi Associated with the Wheat Crown Rot Complex in Oregon and Washington.

Crown rot of wheat in the Pacific Northwest is caused by a complex including Bipolaris sorokiniana, Fusarium avenaceum, F. culmorum, F. pseudograminearum, and Microdochium nivale.

Plant-Parasitic Nematodes Associated with Reduced Wheat Yield in Oregon: Heterodera avenae.

Heterodera avenae is widely distributed in the western United States, where most wheat is grown in non-irrigated winter wheat/summer fallow rotations in low rainfall regions. Economic and social pressures have motivated growers to pursue a transition from winter wheat/summer fallow rotation to no-till annual spring cereals. Annual cereals are also planted in some irrigated fields.

Crop Damage Estimates for Crown Rot of Wheat and Barley in the Pacific Northwest.

Crown rot of wheat and barley in the Pacific Northwest is caused by a complex of Fusarium pseudograminearum, F. culmorum, F. avenaceum, Bipolaris sorokiniana, and Microdochium nivale.

Pratylenchus thornei Associated with Reduced Wheat Yield in Oregon.

Pratylenchus thornei reaches high population densities in non-irrigated annual cropping systems in low-rainfall regions of the Pacific Northwest. Two spring wheat varieties with different levels of tolerance and susceptibility to P. thornei were treated or not treated with aldicarb in three experiments.

Economic impact of Hessian fly (Diptera: Cecidomyiidae) on spring wheat in Oregon and additive yield losses with Fusarium crown rot and lesion nematode.

Damage caused by Hessian fly, Mayetiola destructor (Say), was quantified in spring wheat, Triticum aestivum L., trials near Pendleton and Moro, OR, during 2001 and 2002. Five field experiments were established to examine genetic resistance to Fusarium crown rot, Fusarium pseudograminearum (O'Donnell & Aoki), and economic damage by lesion nematode, Pratylenchus neglectus (Rensch, 1924) (Filipjev Schuurmanns & Stekhoven, 1941) and Pratylenchus thornei (Sher & Allen, 1941).

Nematodes in dryland field crops in the semiarid pacific northwest United States.

Soils and roots of field crops in low-rainfall regions of the Pacific Northwest were surveyed for populations of plantparasitic and non-plant-parasitic nematodes. Lesion nematodes (Pratylenchus species) were recovered from 123 of 130 non-irrigated and 18 of 18 irrigated fields. Pratylenchus neglectus was more prevalent than P.