Plant Disease Management Handbook

By H. M. Rivedal

Cause The fig mosaic virus (FMV) is a single-stranded RNA virus that is transmitted by the eriophyid mite, Aceria ficus. FMV can also be transmitted by vegetative propagation and grafting but not by seed. Mites can overwinter in buds on fig trees. The disease has been observed in both Oregon and Washington and is common on the central California coast.

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Radicchio (Cichorium intybus)

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Radicchio (Cichorium intybus)

Cause The bacterium Agrobacterium tumefaciens enters plants through wounds, either natural or caused by pruning, grafting, mechanical injury, chewing insects, or the emergence of lateral roots. Pruning or cutting tools that cut through galls can become contaminated with the bacteria and spread them to cut surfaces of subsequently pruned plants. Galls can also occur at sites of lateral shoot removal or pinching of terminals. The bacteria can be systemic in plants.

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Radicchio (Cichorium intybus)

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Bellflower (Campanula spp.)

By B. Warneke and J. Pschiedt.

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Wheat (Triticum aestivum) - Fusarium Head Blight (Scab)

Cause The fungus, Botrytis cinerea. This fungus has a wide-host range and is common throughout the year in western Oregon. Plants with injury to the flower bracts due to frost, slugs, snails, or insect damage, are especially susceptible to Botrytis infections.

Cause Several different fungi can colonize the open sinus of certain apples such as 'Delicious', 'Golden Delicious', 'Gravenstein', and 'Idared'. These cultivars have an open sinus that extends from the calyx (flower) end into the core. Alternaria alternata and A. tenuissima colonize the floral tissue during flowering and cause a dry core rot.