Maintaining Disease-Free Geranium Stock Plants...The Impossible Dream?

Greenhouse Crops
The Oregon State University affiliated author discusses methods and practices used to reduce or eliminate disease in geranium stock plants. Common geranium pathogens include Botrytis, Pythium, Rhizoctonia, Thielaviopsis, Xanthomonas, and Verticillium wilt.

Aphids in Greenhouse Crops

The most common aphid species causing problems in greenhouse crops are the green peach aphid (Myzus persicae), melon/cotton aphid (Aphis gossypii), chrysanthemum aphid (Macrosiphoniella sanbomi), rose aphid (Macrosiphum rosae), potato aphid (M. euphorbiae), and the leaf-curling plum aphid (Brachycaudus helichrysi).

Greenhouse Management of Western Flower Thrips and Tomato Spotted Wilt Virus

Greenhouse Crops
The Western flower thrip (Frankliniella occidentalis), a vector of tomato spotted wilt virus, is discussed. Information is provided on the following topics; the virus, thrips identification and lifecycle, management, barriers, monitor, chemical controls, and sanitation.


Information provided by the author intended to aid in the identification and management of the greenhouse whitefly (Trialeurodes vaporariorum) and the sweetpotato whitefly (Bremisia tabaci). Monitoring whiteflies, chemical control and whitefly resistance, and biological control are discussed.

Use of Yellow Sticky Traps in Greenhouses

Greenhouse Crops
A brief report on the yellow stick traps used in greenhouses to monitor and/or reduce certain pest populations. The topics discussed include; types of pests caught by the traps, how often to check traps, where to put traps, how many traps to use, and whether traps should be vertical or horizontal.

Update on Western Flower Thrips

An update for the greenhouse industry regarding the Western flower thrips and tomato spotted wilt virus. Growers were starting to report western flower thrip resistance to certain insecticides. Western flower thrips lifecycle along with possible control methods are discussed by the authors.

Update on Tomato Spotted Wilt Virus

Greenhouse Crops
Increasing number of reports of greenhouse crops displaying symptoms of tomato spotted wilt virus (TSWV) prompted the authors to address the issue. Topics discussed are; the history of TSWV in the US, the wide variety of ornamental and non-ornamental hosts, symptoms, and control.

Tomato Spotted Wilt Virus in Greenhouse Crops

Greenhouse Crops
A brief report on tomato spotted wilt virus (TSWV). The discussion focuses on host plants for the disease, which includes a wide range of flowering greenhouse crops, common weed hosts, and vegetable crops. The author also addresses transmission and control of TSWV.

Xylella fastidiosa, A Newly Named Bacterium, Causes Leaf Scorch on Several Shade and Fruit Trees

Plant Disease
Information on the bacterium Xylella fastidiosa which is closely related to Xanthomonas. Xylella fastidiosa was found in the following shade and fruit trees; American elm, American sycamore, red oak, red maple, mulberry, periwinkle, grape, almond, plum, peach and from ragweed.

Root Weevils

A discussion about root weevils that attack dozens of ornamental plant species in the Pacific Northwest; the Black Vine Weevil (Otiorhynchus sulcatus), the Strawberry Root Weevil (O. ovatus), and the Obscure Root Weevil (Sciopethes obscurus). Topics included in the discussion are biology, control, application, and nematodes.