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Search Results for ' Grapes--Diseases and pests'
PAL Questions: 2 - Garden Tools:
I am looking to install wine-producing grapes in my back yard, but I want to purchase vines from a reputable company, especially since I want to minimize the chance of exposure to Phylloxera. Where would you recommend I shop for the 12-20 vines I would like to install in my back yard?
While I cannot guarantee that any of these nurseries sell stock that is free of Phylloxera, here are three reputable nurseries that may have what you are looking for:
Source: Susan Hill. The Pacific Northwest Plant Locator 2000-2001.
If you would like to know more about Phylloxera, Oregon State University's booklet, Grape Phylloxera: Biology and Management in the Pacific Northwest discusses the subject in great detail.
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We've got an established grapevine that has acquired erineum mites, and a horticulturalist advised us to use dormant spray this fall. The dormant sprays are rather nasty things, and I recently ran across Neem oil, which says it acts as a miticide. It sounds like the concentrated Neem oil is pretty nasty, too, but I'm wondering: (1) will Neem oil work to get rid of the mites; and (2) is it any less harmful to the environment than the traditional dormant sprays?
According to the University of California, Davis Integrated Pest Management program, Erineum mites will not adversely affect your grape crop, they merely cause an aesthetic problem (disfigured leaves).
Washington State University Extension does mention using dormant-season horticultural oils or wettable sulfur. (Search for grape on the left side of the web page). Excerpt:
The grape erineum mite, Collomerus vitus, is actually a type of eriophyid mite. They are very tiny, whitish, worm-like, and spindle-shaped. Their bodies have definite annulations or rings, and only two pairs of legs directly behind the mouthparts. They overwinter under outer bud scales and feed on leaves during summer. The upper leaf surface becomes blistered, and blisters on the lower leaf surface turn white, yellow, or brown. Colonies of mites live inside the blisters (erinea) formed by their feeding on the lower surfaces. The blisters contain masses of enlarged leaf hairs. Large infestations can cause major stress on young vines. From mid-August to leaf drop, the mites migrate back to the overwintering sites beneath bud scales.
Apply according to label instructions. Dormant-season horticultural oils or wettable sulfur applications may be helpful. If you choose to use a pesticide, some examples of products that are legal in Washington are listed below.
Always read and follow all label directions.
- Bonide All Seasons Horticultural & Dormant Spray Oil
- Bonide Lime Sulfur Spray
- ferti-lome SCALECIDE
- R-T-U Year-Round Spray Oil
- Sunspray Ultra-Fine Year-Round Pesticidal Oil
- This list may not include all products registered for this use.
I have only seen references to serious damage from this pest when the grapevine affected is very young, so you may be able to do nothing at all. Neem's effectiveness as a miticide is as yet unproven, and when selecting a Neem-based product, you have to make sure it actually contains the active ingredient said to affect insects, Azadirachtin--some "Neem" products do not. (Also, Azadirachtin affects good bugs as well as the ones you may be trying to control, so it is definitely not risk-free).
Paghat's Garden website article on the "Myth and Reality of Neem Worship"
Although most horticultural oils are petroleum-based, there are supposedly a few out there which are being made with vegetable oil, which would be a preferable alternative if you really needed to spray for the erineum mites. Colorado State University Extension has an article on dormant oil.
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June 24 2013 12:55:25