FIMBY: Change is in the autumn air

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