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Search Results for ' Vegetables--Diseases and pests'

PAL Questions: 5 - Garden Tools:

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Keywords: Brassicaceae (Mustard/Cress family), Vegetables, Vegetables--Diseases and pests

PAL Question:

We have a couple of beautiful heads of cauliflower and a nice set of broccoli. The cauliflower looked nice until we cut through it to find lots of little bugs, turning some of the flower inside dark. We have a few aphids on our mustard greens, but the cauli bugs do not look like aphids.

Is it possible to grow ANY Cruciferae up here without infestations? I have NEVER been able to grow ANY type without some kind of bugs. At least the aphids wait until the bok choy flowers before they infest....and our yard has lots of ladybugs! Is there any hope?

View Answer:

We recommend that you start your seeds indoors to reduce the threat of insect infestation. Once the plants have begun to establish themselves, you can move them outdoors.

These books have great information about growing vegetables in the Pacific Northwest:

Growing Vegetables West of the Cascades: The Complete Guide to OrganicGgardening (by Steve Solomon, Sasquatch Books, 2007)
Sunset Western Garden Book of Edibles (Sunset, 2010)
Winter Gardening in the Maritime Northwest(by Binda Colebrook).

Colebrook explains that crucifers are "susceptible to attack by clubroot, cabbage loopers, imported cabbageworms, cabbage maggots, and gray aphids." Sunset recommends that to prevent pests, "plant in a different site each year. Row covers will protect plants from aphids, cabbage loopers, imported cabbage-worms, and cabbage root maggots. Collars made from paper cups or metal cans (with ends removed) deter cutworms, which chew off seedlings a the base."

Season All Season
Date 2008-01-10
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Keywords: Artichokes (common), Cutworms, Vegetables--Diseases and pests, Slugs

PAL Question:

I have about 20 healthy artichokes. They did not die back in the winter. I think that there is a lot of bug activity going on in them: earwigs, slugs. Should I cut the plants to the ground and dispose of the possible bugs that have wintered over in them? I hate to do it because the foliage is so lovely.

View Answer:

I have grown artichokes for the last 5 years, so I am going to answer from personal experience.
Do not cut the plants back because they will be sending up their flowers in the next few weeks (depending on the weather, it could be as late as June). Cutting it back now will just delay any flowers for at least 6-8 months, if not kill them outright. While I too have had numerous slugs, earwigs and cutworms, I find that their damage is minimal, and does not hurt the flower show. And for eating I just wash them carefully and then turn a blind eye when I find a few earwigs in the pot after cooking!
Sprinkling some Sluggo (or comparable less toxic slug bait) into the leaf joints will help too.

Season Spring
Date 2006-11-02
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Keywords: Powdery mildew diseases, Perovskia, Vegetables--Diseases and pests

PAL Question:

Last year I planted 25 gorgeous Russian Sage in 1 1/2 gal pots. They were fabulous last year, but barely came back this year. We had a mild winter here in New Jersey, but even so, I know that is not an issue with that plant as I've grown it for years. This year I planted an additional 40 in the same hillside and they are doing phenomenally well. On last year's plants, some have flowered a tiny bit, but none have come back to the size they were and most are so small, they look like they came from a 6-inch pot! Do you have any thoughts as to what I can do to improve the situation?

Also, although we haven't had much rain, I am seeing what I'm assuming is mold on several of my plants: trumpet vine, roses, honey suckle. The zucchini and cucumbers have been totally decimated so there is no fruit. White is covering the leaves and with the veggies, the leaves are crumbling and disintegrating.

View Answer:

There are a few possibilities for the poor showing of your Russian Sage (Perovskia atriplicifolia) plants. However, without knowing more details about the growing conditions, I may be offering you advice that does not help. If the pots you selected to grow your plants in were made of a thin material, there is a chance you did not provide them with enough protection from the winter temperatures. Planting them directly into the ground can help to avoid this, if it's possible for you to do so in their location.

Depending on the amount of sun and moisture your plants are receiving, poor growth can result. Russian Sage plants like "a well-drained soil and need to have a warm to hot, sunny position" in the garden. (The Cultivation of Hardy Perennials by Richard Bird published in London by B.T. Batsford Ltd in 1994) If the soil is too wet, root rot can occur.

If they are in the proper cultural environment (lots of sun and well-drained soil), then perhaps they are lacking nourishment. The Plant Care Manual by Stefan Buczacki (published by Crown Publishers in New York in 1993), suggests feeding your plants with a general purpose fertilizer in mid-spring and in mid-summer.

As for your second question, I believe what you are describing is a case of powdery mildew. It is a fungus that shows itself in times of dry weather. The main thing you will need to do is destroy all the foliage affected by the mildew. The mildew on infected foliage will spread to new foliage.

Powdery mildew thrives where plants are crowded and there isn't enough air circulation, so give your plants space, a sunny site, and try watering in the morning, and watering from beneath the plants (not over the leaves) so they are able to dry off during the course of the day.

Here is a link to the University of California-Davis, Integrated Pest Management website. You can learn more about this fungus, including host plants, life cycle and management.

Colorado State University Cooperative Extension has some information about powdery mildew as well, including preventative measures and a recipe for making your own baking soda fungicide.

Season All Season
Date 2007-08-02
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Keywords: crop rotation, Vicia faba, Vegetables--Diseases and pests

PAL Question:

I have small ants on my fava beans and it appears that some of the young pods are blackening. Do ants eat fava beans? Is there anything I can do this year, or should I just start over next time in a different location?

View Answer:

The ants may be visiting the extrafloral nectaries of your fava bean plants! (see this photo of just this activity)

Apparently, some insects are attracted to the nectar of Vicia faba, as this Oregon State University Extension page describes:
"Many beneficial insects, including predatory wasps and lady beetles, are attracted to the nectar of flowering fava bean.
Fava bean also has extrafloral nectaries on its stipules, the leaf-like structures at the base of the leaf petioles. Extrafloral nectar is available to short-tongued insects that do not have access to the nectar of the legume flowers. Both beneficial and pest insects (e.g., lygus bug) feed on extrafloral nectar.
Fava bean is susceptible to aphid damage, especially from the bean aphid. Although aphids usually do not affect fava bean's utility as a cover crop, they can cause considerable damage to the seed. Broadbean weevils also can reduce seed yields."

Here is similar information, from Golden Gate Gardener.

It's possible that the blackening is from aphid honeydew, or perhaps it could be chocolate spot, which is a fungal disease (Botrytis fabae). Here is more about this, from the Royal Horticultural Society.

Practicing crop rotation might be beneficial with your favas as it is with other edible plants. Below is additional information on vegetable crop rotation.
Washington State University Extension: Vegetable Garden Evaluation and Planning Ahead
Penn State: Crop Rotation

To check your favas for botrytis or other diseases, take samples to a Master Gardener Clinic for diagnosis.

Season All Season
Date 2010-06-04
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Keywords: Vegetables--Diseases and pests, wireworms

PAL Question:

Our community vegetable garden has been overrun with wireworms this year. Is there anything we can do to control them?

View Answer:

Here are the links I've located which mention some organic controls for wireworms:
Cyber-Help for Organic Farmers (British Columbia) mentions prevention with planting Brassica crops, use of beneficial nematodes, drying, letting the area go fallow, etc.
Wireworm Biology and Nonchemical Management in Potatoes in the Pacific Northwest (specific to potato crops in the Pacific Northwest, but includes useful information that shows the science to back up suggestions in the previous link)

As you might expect, organic methods are not the toxic silver-bullet approach to pest management--they are longer range. You might have community gardeners plant their crops in containers for the time being (or maybe someone would be willing to donate raised beds?).

I consulted Backyard Bounty: The Complete Guide to Year-Round Organic Gardening in the Pacific Northwest by Linda Gilkeson (New Society Publishers, 2011). Here's a summary of what she says:

  • Check the soil for the eggs of adult beetles in April and May.
  • "Wireworms can be especially damaging for the first few years after new sod is turned for a garden."
  • Larvae take 3-6 years to develop into adults. The worst damage is in spring and fall when they feed close to the soil surface. In summer and winter, they burrow deeper--but they also do this when there is nothing to eat. As you have already noticed, they are attracted to plant roots.
  • Planting late avoids some wireworms. The author recommends not planting fall rye as a cover crop, as it attracts adults to lay eggs there. "Instead of cover crops, I prefer to keep empty garden beds weed-free all winter and use compost and leaf mold to add organic matter. Sow extra seeds of peas, beans and corn to allow for losses. Lightly fork over the soil in annual beds several times before planting and pick out wireworms; their light color makes them easy to see against the soil."
  • She suggests removing all weeds and roots from the bed. Then, use chunks of potato and carrot as bait, skewering each chunk on a short stick (to serve as a marker) and bury the pieces a few inches deep in the soil. Pull up the wireworm traps every day or two and destroy the worms. "For heavily infested soil. it might be worth trying 'trap crops.' Starting with bare soil, about 10 days before you want to plant the bed, sow rows of wheat or barley (about four seeds per inch) about a yard apart. The germinating seeds attract the wireworms if there are no other roots in the soil. After 10 days, pull the grain seedlings and destroy any wireworms found in the soil along the row and among the roots."
  • About parasitic (beneficial) nematodes, she says that the only species that has shown some effectiveness against wireworms is Heterorhabditis bacteriaphora.

Season All Season
Date 2014-06-28
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June 24 2013 12:55:25