Cooler weather and more moisture bring pest, fungal issues
Brassicas come under attack this time of year from cabbage moth caterpillars. The ragged, chomped edges on these leaves are typical of their damage. The holes in the middle of the leaves could be from birds. Kathy Morrison
This is another installment in our Food in My Back Yard series, dedicated to edible gardening.
Have you noticed the mosquitoes? What about the aphids?
Our first atmospheric river of the season brought welcome rain. But that moisture woke up several pests – especially mosquitoes. Recent summery days in the 80s helped eggs to hatch. Mature mosquitoes literally came out of the woodwork, where they lurk. Some species are particularly active in fall.
The solution? Wear mosquito repellent along with long sleeves and pants while working outdoors. Make sure to dump any standing water that may have accumulated from that recent rain.
That precipitation also prompted fall growth on plants. Transplants of cool-season vegetables are growing quickly. All that tender new growth is a magnet for aphids, which multiply exponentially.
Before they chow down, knock aphids off plants with a strong stream of water from the hose. Or blast them with some insecticidal soap or try this home-made solution:
In a blender, combine three or four cloves of garlic with one cup of water; blend until well chopped. Strain the solution. Add 1 teaspoon mild dish soap (such as Ivory). Put that “bug soap” in a pump sprayer and squirt those little pests away. (This bug soap works on several other little pests such as whiteflies, which are also having a big surge.)
Keep the hose out; you may need it for spider mites.
After summer heat and dusty dry conditions, spider mites built up giant colonies, especially in shrubs. They loved recent summer-like temperatures in the 80s, too. They’ll continue to stick around until rain or a strong blast from the hose knocks them off plants.
Late-season caterpillars are munching holes in anything edible, especially lettuce and brassica vegetables (kale, cabbage, broccoli, cauliflower). Look on the underside of leaves and pick them off. Row covers can keep those pretty white butterflies (actually white cabbage moths) from laying their eggs on the plants.
Snails and slugs also like cooler weather – and eat everything. Pick them off when they’re most active (about an hour after nightfall).
Mild fall temperatures in the 70s – the forecast for most of this week – also bring out a plethora of fungal issues.
When high temperatures cool into the 70s (as we’ll see this week), powdery mildew suddenly returns. This fungal disease is easy to spot; it looks like someone dusted foliage with flour.
Expect to see an explosion of powdery mildew on roses and other susceptible shrubs. Squash and pumpkins usually attract it, too. This fungal disease lurks in old mulch or fallen leaves under bushes. If leaves look puckered (but not yet dusted with white), pick them off; that puckering precedes the spores.
According to UC master gardeners, there are many species of powdery mildew; each attacks a specific plant. Among the susceptible crops are: artichoke, beans, beets, carrot, cucumber, eggplant, lettuce, melons, parsnips, peas, peppers, pumpkins, radicchio, radishes, squash, tomatillo, tomatoes, and turnips.
This fungal disease is so prevalent because powdery mildew loves this kind of weather, add the master gardeners. “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.”
Rust, another fungal disease, returns in late October with a vengeance. Again, it’s the weather. Rust spores look like orange specks on the underside of rose leaves. By removing infected leaves early, you can stop a major outbreak. Pick up fallen foliage to prevent rust from returning next spring.
More on powdery mildew: https://ipm.ucanr.edu/home-and-landscape/powdery-mildew-on-vegetables/pest-notes/#gsc.tab=0
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Flowers in My Back Yard Series
July 7: Grow these bright cosmos for bees and butterflies
June 30: Agapanthus adds blue fireworks to the garden
June 23: Easy-care gazanias fill those hot corners
June 16: Daylilies are perfect for water-wise gardens (and a lot more)
June 9: Grow coneflowers for pollinators -- and yourself
June 2: Sunflowers capture Sacramento's summer attitude
May 29: Are your roses going 'blind'?
May 26: Zinnias are the summer flowers every garden needs
May 19: Plant dahlias now for late-summer flower power
May 12: Know your coreopsis from your bidens
May 5: Mums the word on Mother's Day weekend
April 28: Majestic Matilija poppy is worth a look
April 21: Celebrate roses, America's favorite flower
April 14: Small flowers with outsized impact
April 7: Calendulas do double duty
April 3: Make Easter lilies last for years to come
March 31: In praise of a pollinator magnet (small-leaf salvias)
March 24: Azaleas brighten shady spots
March 17: The perfect flower for beginners? Try zonal geraniums
March 10: Keep camellias happy for years to come
March 3: Fruit tree blossoms are a fleeting joy
Feb. 27: Are your roses looking rusty?
Feb. 24: Treasure spring daffodils now and for years to come
Feb. 17: How and why to grow wildflowers
Feb. 10: Let's talk Valentine's Day roses
Feb. 3: Why grow flowers?
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Garden checklist for week of July 12
Get out early in the morning to take care of garden chores. Temperatures are expected to stay below 80 degrees before 10 a.m.
* Remember to water early and deep; your garden depends on you.
* It’s not too late to add a splash of color. Plant petunias, snapdragons, zinnias and marigolds.
* From seed, plant corn, pumpkins, radishes, winter squash and sunflowers.
* Keep your vegetable garden watered, mulched and weeded. Water before 8 a.m. to reduce the chance of fungal infection and to conserve moisture.
* Water before fertilizing vegetables and blooming annuals, perennials and shrubs to give them a boost. Feeding flowering plants every other week will extend their bloom.
* Feed vegetable plants bone meal or other fertilizers high in phosphate to stimulate more blooms and fruiting.
* Don’t let tomatoes wilt or dry out completely. Give tomatoes a deep watering two to three times a week. Harvest vegetables promptly to encourage plants to produce more. Squash especially tends to grow rapidly in hot weather. Keep an eye on zucchini.
* If your melons and squash aren’t setting fruit, give the bees a hand. With a small, soft paintbrush, gather some pollen from male flowers, then brush it inside the female flowers, which have a tiny swelling at the base of their petals. (That's the embryo melon or squash.) Within days, that little swelling should start growing.
* Pinch back chrysanthemums for bushy plants and more flowers in September.
* Remove spent flowers from roses, daylilies and other bloomers as they finish flowering.
* Pinch off blooms from basil so the plant will grow more leaves.
* Cut back lavender after flowering to promote a second bloom.
Contact Us
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Food in My Back Yard (FIMBY) Series
Lessons learned during a year of edible gardening
WINTER
Is edible gardening possible indoors?
Hints for choosing tomato seeds
Why winter is the perfect time to plant fruit trees
When to plant? Consider staggering your transplants
How to squeeze more food into less space
Plant a fruit tree now -- for later
Win the weed war by tackling them in winter
Tips for planting bare-root trees, shrubs and vegetables
Time to give vegetable seedlings some more space
Ways to win the fight against weeds
FALL
Dec. 16: Add asparagus to your edible garden
Dec. 9: Soggy soil and what to do about it
Dec. 2: Plant artichokes now; enjoy for years to come
Nov. 25: It's late November, and your peach tree needs spraying
Nov. 18: What to do with all those fallen leaves?
Nov. 11: Prepare now for colder weather in the edible garden
Nov. 4: Plant a pea patch for you and your garden
Oct. 27: As citrus season begins, advice for backyard growers
Oct. 20: Change is in the autumn air
Oct. 13: We don't talk (enough) about beets
Oct. 6: Fava beans do double duty
Sept. 30: Seeds or transplants for cool-season veggies?
Sept. 23: How to prolong the fall tomato harvest
SUMMER
Sept. 16: Time to shut it down?
Sept. 9: How to get the most out of your pumpkin patch
Sept. 2: Summer-to-fall transition time for evaluation, planning
Aug. 26: To pick or not to pick those tomatoes?
Aug. 19: Put worms to work for you
Aug. 12: Grow food while saving water
Aug. 5: Enhance your food with edible flowers
July 29: Why won't my tomatoes turn red?
July 22: A squash plant has mosaic virus, and it's not pretty
July 15: Does this plant need water?
July 8: Tear out that sad plant or baby it? Midsummer decisions
July 1: How to grow summer salad greens
June 24: Weird stuff that's perfectly normal
SPRING
June 17: Help pollinators help your garden
June 10: Battling early-season tomato pests
June 3: Make your own compost
May 27: Where are the bees when you need them?
May 20: How to help tomatoes thrive on hot days
May 13: Your plants can tell you more than any calendar can
May 6: Maintain soil moisture with mulch for garden success
April 29: What's (already) wrong with my tomato plants?
April 22: Should you stock up on fertilizer? (Yes!)
April 15: Grow culinary herbs in containers
April 8: When to plant summer vegetables
April 1: Don't be fooled by these garden myths
March 25: Fertilizer tips: How to 'feed' your vegetables for healthy growth