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Powdery Mildew on Peas

Select powdery mildew resistant or tolerant varieties!

Cornell University’s lists of Disease Resistant Varieties

  • Longbeans
  • Green beans:  Provider, Merpatim, Parkit, Perkutut, Sriti
  • Cucumber: Diva, Cumlaude, Media F1.  Slicers:  Cornell’s list
  • Muskmelon:  Ambrosia F1, Primo (western type), Sun Jewel
  • Pea:
    • Ambassador – Resistant to powdery mildew, entation virus and fusarium wilt
    • Cavalier – Good resistance to powdery mildew.
    • Greenshaft – Resistant to downy mildew and fusarium wilt
    • Rondo – Resistant to fusarium wilt
    • Downy Mildew resistant peas:  Kelevdon Wonder, Oasis, Twinkle, Avola, Hurst Greenshaft, Ambassador, Cavalier and Peawee.
  • Pumpkin: 18 Karat Gold, Gladiator
  • Winter Squash:  almost all varieties
  • Yellow Summer Squash: Success, Sunray, Sunglo
  • Zucchini: Ambassador, Wildcat, Cornell’s list

Healthy Practices Make a Difference!

Plant in full sun!
Plant so leaves of one plant don’t touch another and spread the spores.
Remove any debris or dead leaves breeding habitat.
Remove and don’t compost infected leaves.  If  you don’t remove them, you reinfect your plant each time you water. 
Wash tools and your hands before you go from one plant to the next.
Water in the AM, at ground level.  No overhead watering.
BEFORE you have mildew, while your plants are still babies, drench the leaves with a baking soda/milk mix.  Tablespoon Soda, ¼ cup nonfat milk powder, drop of liquid dish detergent in a watering can.
Drench weekly with your mix.  But if you think you aren’t going to be able to get rid of the mildew, sadly, do the one cut prune.  Remove that plant so it won’t infect others – yours or your neighbors’.  Do this sooner than later.  Mildew is windborne, so the more mildew, the more is spread.

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Slugs and Snails can eat a plant overnight, only the bare stem remaining, if that.   Some good strategies are below.  For important details, please see University of California, Integrated Pest Management (IPM) Snails and Slugs

  • Remove hiding places – leave a few hiding places (traps), remove the snails that gather there
  • Use drip irrigation to reduce humidity and moist surfaces = less habitat
  • Choose snail proof plants as possible
  • Use copper barriers – remember you have to polish them to keep them working
  • Make habitat for natural enemies ie tall poles for birds
  • Use bait like Sluggo/Escar-Go.  Sluggo is organic, safe for birds and animals, pets and children, can be used on the day of harvest, and is effective even after watering or rain!  Is it really ‘organic?’  See this article by conscientious Golden Gate Gardener

Aphids/White Flies Season  Keep an eye out for these critters in your broccoli, cabbages and kale.  The simplest thing to do is spray ‘em with a jet of water from the hose, both topside and underneath the leaves!  If the infestation gets beyond your tolerance, or the plant gets badly stunted or loses its healthy shape, remove the plant – don’t compost it.  Don’t procrastinate on this because aphids/white flies spread quickly.  This is one of the prime reasons to plant the same kind of plant in separate groupings or areas, rather than all in a row or a bunch, so the invaders can’t walk plant to plant.  If you do that, plant them far enough apart so their leaf tips don’t touch, or keep them trimmed so they don’t.  Keep a close watch!

Preventing Powdery Mildew!  Powdery mildew spores are wind spread to new hosts – that means from your plant to mine, or mine to yours!  Powdery Mildew is a common fungal disease that affects many types of plants.  The fungus will coat leaves, stems and flowers.  It looks like a white fuzz or powder, usually starting on shaded lower leaves, in that damp, humid microclimate, especially if we are watering frequently, not letting the area dry out.  This can lead to serious crop damage, low to no production, if left unchecked and can infect crops at any stage of the plants life.  However, UC Davis says ‘Powdery mildews generally do not require moist conditions to establish and grow, and normally do well under warm conditions; thus they are more prevalent than many other leaf-infecting diseases under California’s dry summer conditions.’  Darn.  More at UC Davis IPM on Powdery Mildew

Here are some inexpensive home remedies:

Prevention:  Dilute 1 part nonfat milk, with 10 parts water.  Spray liberally on affected plants.  Do not spray on plants when in flowering stage.  This treatment works so well usually one treatment is sufficient. Be sure to add a half teaspoon liquid dish soap so your mix will stick.  See about research and more details at Appalachian Feet.

Spraying milk on infected plant leaves with a solution of nine parts water to one part milk has shown to decrease powdery mildew by 90%. It has been reported that milk can boost the plant’s immune system, which also helps to fight powdery mildew and other diseases.

Preventative/Cure:  Baking Soda and Epsom Salt Remedy.  Baking soda increases pH levels on the leaf surface which will makes it difficult for the fungi spores to survive.  Foliar spray the plants liberally.  Wash off after one or two days.  The solution will leave a white haze on the leaves of the plants which does looks similar to the mildew.

1 quart water, 1 teaspoon baking soda (sodium bicarbonate) (or 1 Tablespoon to a gallon), 1 T Epsom Salt/Gallon
1 teaspoon cooking oil (canola, soya, whatever)
A drop or two of dishwash or soft soap (to disperse the oil and make it stick)
Apparently it has been found that either the oil or the soda will do the job, but they do better together. However, one needs to test the oil first as some sorts of foliage can be damaged by it.

If the mildew has already taken hold one can get rid of a lot of the spores and make the spray more effective by thoroughly hosing the leaves first.

Brief note on Epsom Salt, 13 % Sulfur. I read a post saying there is no research proving the use of Epsom Salt for fungus. Two paragraphs later, the same post says ‘Once an infected plant is pruned of all affected parts [having powdery mildew], it helps to spray the plant with an effective fungicide, including sulfur, lime-sulfur, neem oil or potassium bicarbonate [baking soda].’ Many gardeners swear by Epsom Salts as well. Try it!

Milk & Baking Soda is the third possible combination used effectively! While you are at it, add one crushed regular strength Aspirin! Salicylic acid, in aspirin, triggers a defense response in your plants!

All these recommendations are organic and completely safe to use. No safety clothing or gear needed.

5 Liter Red Dramm Watering CanDepending on how many plants you need to treat, you can use a hand spray bottle, a hose attached sprayer, a backpack rig or your watering can with a rose nozzle that turns up. This is probably the most efficient for the average home gardener. The idea of foliar treatment, or feeding, is to spray the whole plant, both tops and bottoms of leaves. A lightweight plastic can with a long spout gets into your plant and you can lift it higher for trellis plants like beans, peas, cucumbers, squashes. The Dramm Can rose can be twisted so the spray goes upward to get the undersides of the leaves where pests and diseases hang out.

Please!  Be a good neighbor.  Prevent this common fungus, don’t let it blow into your neighbor’s veggies!

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The Green Bean Connection newsletter started as correspondence for the Santa Barbara CA USA, Pilgrim Terrace Community Garden. All three of Santa Barbara city community gardens are very coastal. During late spring/summer we are in a fog belt/marine layer area most years, locally referred to as the May grays, June glooms and August fogusts. Keep that in mind compared to the microclimate niche where your veggie garden is.

Love your Mother! Plant bird & bee food! Think grey water! Grow organic! Bless you for being such a wonderful Earth Steward!

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What’s happening with my tomatoes?! 

Early BlightFusarium Wilt, Verticillium WiltLate Blight

Tomato – Healthy SunGold!

Tomato – Verticillium Wilt, Yellow Flag effect

This?!                                                 Or this?

This is bar none, the most common summer question I get asked! Potatoes, tomatoes, and the various forms of lettuce are the top three favorite vegetables in the US, so you can see why this is THE question! Since fungi spread as simply as by the wind, I will be campaigning for more tomato plant care, starting with what people can do now to keep the fungi from overwintering, then in the spring to lessen its chances. There are more things that can be done than I knew! Read on!

About Fungi  To emphasize the potency of these fungi: Late Blight of potatoes and tomatoes, the disease that was responsible for the Irish potato famine in the mid-nineteenth century, is caused by the fungus-like oomycete pathogen Phytophthora infestans. It can infect and destroy the leaves, stems, fruits, and tubers of potato and tomato plants. Before the disease appeared in Ireland it caused a devastating epidemic in the early 1840s in the northeastern United States. Not only do the fungi feed on your tomato plants, but take a look at your potatoes, peppers, eggplant, cucumbers and beans! See those yellowing leaves? Remove and dispose of them ASAP! That removes zillions of spores so they can’t spread. The wilts and blights also affect trees! Sadly, not only do your plants look depressing, production is zilch, they die an unnatural death. Remove, replace. Be happy.

How do fungi work?  Spores are spread by rain/watering splash, insects, and wind, and through our hands and tools (wash your hands and tools after handling infected plants) and through these mediums, can travel distances. That’s why it is so important, in our community garden, to tend our plants, so our neighbors’ plants won’t also be infected.  Educate your plot neighbors, better yet, send this to them! Spore spread is most rapid during conditions of high moisture, marine layer days, and moderate temperatures (60°-80°F). Once established, the fungi can over winter in your garden on debris and weeds.

What they look like on your plant: 

Tomato – Early Blight

15 Fungi Preventions!

Cultural control practices alone won’t prevent disease during seasons with wet, cool weather. However, the following measures will improve your chances of raising a successful crop.

Things you can still do this season!** Things you can do now to prepare for next season!**
  1. Buy toms that are tagged VFN, or just VF – that’s Verticillium Wilt and Fusarium resistant or tolerant. Varieties that set fruit early, at lower temps, are Early Girl Improved, Fourth of July, Enchantment. Excellent resistant varieties are Champion, Husky Red, Better Boy, Ace Hybrid, Celebrity.  
  2. Plant only healthy-appearing tomato transplants. Check to make sure plants are free of dark lesions on leaves or stems. If starting transplants from seed, air-dry freshly harvested seed at least 3 days.
  3. Plant cukes and toms on a special raised mound/basin with the bottom of the basin above the regular soil level. See more on this page in the section, Special Planting and Growing Tips!
  4. Remove volunteer tomatoes and potatoes.  If they are a not a resistant or tolerant variety, when they get sick, they increase the chances of your resistant varieties having to fight harder to live, and your good plants may not win the battle.  Do not let volunteers grow, even on compost piles, cute as they are. Infected tomato refuse should be put in the trash, NOT in green waste or your compost.  
  5. **Create a soil barrier, mulch! Newspaper/cardboard covered with mulch or grass clippings doesn’t let the soil dry out. Moist soil is fungi habitat – we want that soil to dry. Use no more than one inch of straw. It is easy to lay on and allows light to get through and air to flow and dry the soil, stops the splash factor. Above all, you don’t want wet soil to contact your plant’s leaves. When that straw gets tired and flattens, trash it and replace with new clean light fluffy straw.   
  6. **Avoid wetting foliage when watering, especially in late afternoon and evening. Water at ground level! Watering the leaves creates a humid micro climate; the fungus produces spores. Dry leaves. Dry leaves. Dry leaves. No moisture, no spores.  
  7. **Air circulation, plant staking and no touching. Air circulation allows the wind to blow through your plants. This allows the timely drying of leaves and it helps break up micro climates. If your plants are packed too tightly together, they themselves become barriers to drying. Staking your plants to poles and using cages helps them grow upright and it creates gaps between the tomato plants. You want wind and sun to reach through and around your plants. And getting more sun, your toms will ripen sooner! Moisture is needed for fungi to spread. Dry is good. Tomatoes should be planted with enough distance that only minor pruning is needed to keep them from touching each other. In the case of tomatoes, scattered interplanting, biodiversity, is always a better choice than row planting where disease easily spreads from plant to plant.  
  8. **Spray proactively. Wettable sulfur works. It is acceptable as an organic pesticide/fungicide, is a broad spectrum poison, follow the precautions. It creates an environment on the leaves the spores don’t like. The key to spraying with wettable sulfur is to do it weekly BEFORE signs of the disease shows. Other products also help stop the spread. Whatever you select, the key is to spray early and regularly.  
  9. **When your toms are about a foot tall, water neighboring plants, but not your toms. Plant water loving companion plants, like Basil or the Plant Dr Chamomile, next to your toms; water them all you want! Make a basin around your toms to keep water OUT! That keeps the soil drier near your plant, so the fungi can’t thrive there. Your tomatoes will get plenty of water by their deep roots.  
  10. **Remove bottom leaves, again, no touching (the ground), and prune your plants. Barbara Pleasant at Mother Earth News says, ‘When the lowest leaves are removed just as the first leaf spots appear, you also remove millions (zillions) of spores. And, because the bases of pruned plants dry quickly, the spread of the disease is slowed because early blight fungi need damp leaves in order to germinate and grow.’ Create an 18 to 24 inch barrier gap or safe space between your garden soil or mulch and the first leaves of the tomato plant. If the spores can’t splash upwards and reach the leaves, they can’t take hold. The stem usually isn’t a place for the spores, though it can be. Best is to remove the bottom leaves before the spores start!
    .
    If you have large plants, you might consider thinning some branches to let the sun and wind blow through the main body of your tomato plant. But, some gardeners don’t recommend pruning or snipping the suckers, the mini branches formed between the trunk and branches, because spores can enter through these cuts. If you decide to prune, the less cuts the better. Prune on hot, dry, unwindy days, mid morning to midday, after dew has dried, so cuts can dry and heal with less chance of airborne fungi getting into them. Try not to touch the cuts after they have been made. Use clippers for a clean cut. Wash your hands, in a rinse of water & alcohol, frequently so you don’t further infect healthy parts of your plant.  
  11. **Remove infected leaves immediately. A leaf should be completely green. Look for brown spots or yellow spots or distress. Remove leaves and prune when it is dry and sunny, not windy. Wash your tools and hands often.  
  12. After the tomatoes set, add some nitrogen. A healthy plant tends to fight off the spores. You don’t want to add too much nitrogen to your tomatoes before they set fruit. Too much nitrogen before fruiting leads to more leaves and less fruit. Add N only once.  
  13. **Rotate your crop if possible. Because fungi also affect other plants, rotation in small gardens isn’t practical or even possible. But if you have the room, move your tomatoes to areas that are fungi free.  
  14. ****At the end of the season remove & trash, don’t compost or put in green waste, all infected debris and surrounding debris. Pull all the weeds because spores can over winter on weed hosts. You want to reduce the number of spores laying in wait.  
  15. **The spores aren’t super spores. During our winter season, turn your soil about 10 inches, burying the spores helps remove them, and it also exposes snail eggs to die.

Preventive Foliar Mix that does wonders! 

Apply every 2 to 3 weeks, so new growth will be covered.  Wet under and over the leaves.  Per gallon add:

  • One crushed regular strength aspirin
  • 1/4 Cup nonfat powdered milk
  • Heaping tablespoon baking soda
  • 1/2 Teaspoon mild liquid dish soap

Water your plants with an aspirin?!  Salicylic acid, in aspirin, triggers a defense response in tomatoes and other plants as well! Adapted from eHow:  The main benefit of aspirin in planting involves aspirin’s ability to fend off potential plant diseases.

  1. Purchase regular strength aspirin. The brand does not matter; purchase the cheapest brand that is available.
  2. Mix together one aspirin with one gallon of water. Combine the ingredients well, so that the aspirin is distributed evenly throughout the liquid.
  3. Add a half teaspoon of mild liquid soap to the mixture. This is used as a way to help the aspirin water stick better to the tomato plants. Once the soap is added, attach a spray nozzle to the gallon jug and it is ready to use.
  4. Spray the tomatoes when you first set them in the ground. Aspirin sprayed directly on seeds improves germination, on plants it stimulates the growing process. There is no need to soak the area. A light and gentle spray will suffice.
  5. Continue to spray the aspirin mixture on the tomato plants every 2 to 3 weeks. You are going to notice that the plants stay healthier and attract fewer insects.

Per a comment by Leroy Cheuvront at Heavy Petal blog:  I have had the blight and have stopped it from destroying my tomato plants. All you have to do is mix 1/4 cup of bleach to a gallon of water and drown the plant from top to bottom, it will not kill the plant. I do it every seven days and the blight has not returned.  — June 18, 2010. It sounds scary, but I bet it works! I would test this principle on ONE plant to be sure it is safe to use.

Solarization  In the past ten years, some enterprising Israelis came up with solarizing. Moist soil is covered with transparent plastic film for four to six/eight weeks in the summer. It takes that long to heat the soil to a temperature and depth that will kill harmful fungi, bacteria, nematodes, weeds, and certain insects in the soil. Some gardeners won’t use solarizing because it kills beneficial soil organisms too… Solarization can be a useful soil disinfestation method in regions with full sun and high temperatures, but it is not effective where lower temperatures, clouds, or fog limit soil heating. Solarization stimulates the release of nutrients from organic matter present in the soil.

Solarization

Solarization also kills grass by heating up the soil when daily temperatures exceed 80°F. Weed eat or mow the area as short as possible. Moisten the soil and cover the area in clear plastic for 10-14 days, until the grass is dead. Although cloudy weather will slow things down by cooling the soil under the film, a few weeks of sunshine will improve your soil dramatically, easily, and inexpensively. If you live in an area with cool or cloudy summers, or if you just don’t want to wait all season, you can speed up the process by adding a second sheet of plastic. Using the hoops commonly used to elevate row covers or bird netting, raise the second sheet of plastic over the ground-level sheet. The airspace between acts as a temperature buffer zone during cloudy weather and the combination of the two sheets of plastic serves to raise the soil temperature an additional 6 degrees. The goal is to raise and maintain temperatures in the top 6 inches of soil to a level between 110 to 125 degrees F. After several days of sunshine, soil temperatures rise to as high as 140 degrees at the surface and well over 100 degrees as far down as 18 inches. Do not mix untreated soil into the solarized bed!

And please, do NOT compost diseased tomatoes, infected trimmings or removed leaves, or any other diseased plant. That’s how you spread soil borne fungi, let alone that they are also spread by wind, are airborne. Put them in the trash, not green waste. If your neighbor has a diseased plant, don’t be shy to respectfully and gently ask them to remove it. Remember, they raised that child. How hard was it for you to give up your plant? Especially the first time. See? They may not even know about wilts. Educate them if possible. Tell them how you learned about it. Offer to send them the link to this page.

Biofumigation  Biofumigation is a sustainable strategy to manage soil-borne pathogens, nematodes, insects, and weeds. Initially it was defined as the pest suppressive action of decomposing Brassica tissues, but it was later expanded to include animal and plant residues. 

Other Tomato Questions & Cures – Holes, spots, brown areas?  Here is an IPM (Integrated Pest Management) image page from UC Davis that is likely to answer your question! It includes diseases and pests. Do take a good look at it!

To the fattest, bestest tomatoes ever!!!! 

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Updated 6.11.19


The Green Bean Connection newsletter started as correspondence for the Santa Barbara CA USA, Pilgrim Terrace Community Garden. All three of Santa Barbara city community gardens are very coastal. During late spring/summer we are in a fog belt/marine layer area most years, locally referred to as the May grays, June glooms and August fogusts. Keep that in mind compared to the microclimate niche where your veggie garden is. Bless you for being such a wonderful Earth Steward!

Love your Mother! Plant bird & bee food! Think grey water! Grow organic!

Read Full Post »

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