Scott Lukas Hemp Diseases and Pests

Slides from a presentation on insect pests and diseases observed on hemp by Scott Lukas of OSU's Hermiston Agricultural Reserach and Extension Center.

Chlorotic leaf spot identification and management (formerly light leaf spot)

Cindy Ocamb, Extension Plant Pathologist, discusses her research on chlorotic leaf spot (formerly light leaf spot, Pyrenopeziza brassicae), how to identify this emergent disease, and management strategies.

Chlorotic leaf spot in Oregon brassicas

Evaluation of combined fungicide and genetic resistance to control white mold in green beans (2015)

The resistance to white mold obtained so far in snap beans has been derived from NY 6020, which provides partial physiological resistance. Under light disease pressure, plants will show few if any symptoms, while under heavy pressure, the plants may show a moderate level of infection (whereas susceptible BBL types will be 100% molded). Cultivars with this form of resistance would not need any supplemental control with fungicides, whereas under heavy pressure, fungicides might be required, but at a reduced frequency or quantity. The objective of this study was to determine whether OR6771 would benefit from an integrated mold control approach that included fungicides typically used in snap production, Topsin M and Rovral tankmixed.

Clubroot (Plasmodiophora brassicae) control strategies on brassicas (2015)

The goals of this project were to determine 1) if liming controls clubroot, 2) the pH that must be attained to achieve commercially viable levels of control, and 3) how best to lime (materials, timing, incorporation strategies) to achieve that pH. Research conducted in 2014 showed that liming clubroot infected soils to a pH ≥7.1 is an effective practice for reducing both the incidence and severity of clubroot. Liming does not kill the pathogen but rather prevents disease spores from infecting the plant. In 2015 the research was focused on the relationship between disease incidence and severity when pH <7.1,better understanding when to apply lime, and how to incorporate to maximize pH change.

Clubroot (Plasmodiophora brassicae) control strategies on brassicas (2014)

This research has demonstrated that liming clubroot infected soils to a pH ≥7.1 is an effective practice for reducing both the incidence and severity of clubroot. Liming does not kill the pathogen but rather prevents disease spores from infecting the plant. This research demonstrated that highly reactive calcitic lime products could be substituted for hydrated lime as they effectively raise the pH of the soil to the target pH of ≥7.1 within a week after application. The project also demonstrated that boron and Serenade drenches did not suppress clubroot under field conditions.

Winter Squash Production Resources

It is difficult to find information on winter squash production and storage. This page aggregates resources relevant to Oregon winter squash growers.

Winter Squash Storage Rots and Their Management

Farmers in western Oregon can lose a significant portion of their winter squash in storage to storage rots. In winters 2012-2015 we collected samples of stored squash with rot symptoms from farmers in western Oregon and the OSU Plant Clinic identified the pathogens causing those rots. This article includes photos of the rot symptoms, descriptions of the diseases, and information on how to control storage rots.

Special Local Need registration for Rovral on Brassica seed crops

this SLN registration is for management of black leg on Brassica seed crops

White Mold of Snap Bean and Other Vegetable Crops

White mold is a serious foliar and pod disease of snap beans grown for processing in western Oregon as well as in all major snap bean production regions in the US. White mold has a wide host range as it is a pathogen on more than 400 plant species.

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