One of the most maddening gardening tasks is pest control. Discovering roses covered in aphids, Swiss chard with more holes than Swiss cheese, or grotesquely distorted citrus leaves may have gardeners feeling all bugs are bad.

The opposite is true, according to UC Cooperative Extension Integrated Pest Management advisor Eric Middleton. The vast number of insects and other arthropods are either beneficial or neutral, he said. Middleton suggests putting away the pesticides and giving bugs the benefit of the doubt, in most cases.

To be sure, there are bugs that cause a lot of damage. The most common garden enemies in California are aphids, thrips, mealybugs, scales, spider mites and caterpillars.

Pests' natural enemies can dramatically reduce pest populations, while they do no harm to plants. Fungi, bacteria and other microbes can cause diseases that kills pests, but the beneficials you are most likely to see are insects. They work by eating or parasitizing pests.

“Natural enemies provide at least $13 billion in pest control services in U.S. agriculture,” Middleton said. They also offer untold benefits to gardens, yards and natural areas in California.

Predators and parasitoids help keep pests in check

Parasitoids live in close association with the pest host and end up killing it, often from the inside out. The most common parasitoids are tiny wasps, but parasitoids also include beetles and flies. These beneficials can be hard to identify because they spend so much of their lives inside the host. The most telling signs are mummified bodies of pests - small, hollow, hardened bumps attached to leaves.

“Parasitoids are very important for pest control,” Middleton said. “They are almost always more impactful than predators.”

Beneficial predator insects eat pests for food. Some are specialists and will only consume one type of pest, other are less picky.

Common specialists include the mealybug destroyer, black beetles that resemble their prey; spider mite destroyer, black beetles that voraciously feed on spider mites; and vedalia beetle, introduced from Australia to combat cottony cushion scale on citrus.

Many lady beetle adults and larvae are generalist predators. They feed on aphids, mealy bugs, white flies, mites and insect eggs. There are many species in California, including the convergent lady beetle, named for the two white markings on the thorax that are angled towards each other; Asian lady beetle, with a white section on the head that looks like a capital M; and seven-spotted lady beetle, which is very round and a deep, dark color.

Lacewings are delicate, green generalist predators. They eat almost any type of living prey. Eggs can be spotted at the end of small stalks perched on leaves. Lacewing larvae look like small alligators with large sickle-shaped jaws. Some lacewing larvae are called trash bugs. The insects, which cover themselves with plant debris for protection, look like moving piles of garbage.

Syrphid flies are also important predators. Their larvae, very tiny green worms, feed on aphids, psyllids and other soft body insects. The adults look like small bees.

Other predator insects include big eyed bugs, minute pirate bugs, praying mantis, predatory thrips, ground beetles and soldier beetles. In addition, spiders of many types feed on larger and flying insects.

How to promote natural enemies?

Many types of predators can be purchased at home stores and garden centers, such as ladybeetles, lacewings, mites and minute pirate bugs. However, UC research has shown that their success in garden settings is mixed.

“You may need to frequently buy and release in order to control pests,” Middleton said. “If pests are a consistent problem, it's often better to improve conditions for natural enemies in your yard or garden.”

To make your garden or yard welcoming to natural enemies, reduce pesticide use. Most pesticides will also knock down natural enemies, even the organic options. If a treatment is necessary, use soaps, microbials, botanicals or oils.

Reduce mowing, tilling and removing debris.

“Stability is better for most natural enemies,” Middleton said. “Mowing and raking reduce habitat. Tilling can kill soil predators and predator larvae. Let your space be a little wild, the more wild, usually the better for natural enemies.”

Biodiversity also boosts natural enemy numbers. Flowers in particular are very important.

“Have a mixture of perennials and annuals, a range of 10 or 15 different species,” Middleton said. “It's good to have native flowers in the mix. They're better adapted to your area.”

For more information about beneficial insects, see the natural enemies gallery on the UC IPM website: https://ipm.ucanr.edu/natural-enemies/

Download a natural enemies poster from UC IPM here: https://ipm.ucanr.edu/IPMPROJECT/ADS/poster_naturalenemies.html

Native to Texas and the Southeast, Turk's cap (Malvaviscus arboreus var. drummondii) gets its common name from the tightly twisted flowers that never fully open and resemble a Turkish turban or fez.

Turk's cap grows rapidly and can reach 4 to 6 feet high and wide with profuse red blooms spring through fall. It's adaptable to a variety of soil types and is very heat and drought-tolerant once established. Plants may bloom better in full sun, but the foliage will suffer; morning sun and afternoon shade is perfect in our area. In fact, Malvaviscus is one of the few perennials that blooms reliably in shade.

In mild winters the plant will be evergreen. It may die back after a hard frost but is root hardy. Prune hard in late winter/early spring. Plants can become somewhat leggy, so cut back by one-third to one-half as needed to encourage denser growth.

Very attractive to hummingbirds and butterflies, Turk's cap is actually a butterfly host plant. Few disease problems but watch for aphids or whiteflies. Turk's cap has bright red flowers, but other varieties bloom pink or white. All in all, an excellent choice to brighten a shady place.

Preparations for severe weather and damage control in home gardens and orchards have become a major focus for Master Gardeners during the last 10 years. California Master Gardeners are helping home gardeners deal with drought, with atmospheric river ‘bombs' that bring high winds, heavy rains and flooding, with heat spikes and with wildfire smoke and ash. This year we also experienced extended cold spells with night time temperatures near freezing until April. 

Here's a brief review of the major problems home gardeners are facing and some ideas for mitigation of the results of severe weather.

Drought: Amend the soil in planting beds with large amounts of compost and humus twice a year to increase water retention and retard runoff. Replace lawns with drought-tolerant plants and California natives and install water-conserving irrigation. New irrigation devices come onto the market every year; check them out frequently. Consistently maintain a three- to four-inch layer of organic mulch. Leave the leaves from healthy trees to decompose in beds rather than removing them. This preserves beneficial micro organisms in the soil and encourages the development of beneficial fungi that create hyphae, or long fungal threads, which add structure to the soil.

Atmospheric river ‘bombs': Prepare for heavy rain and flood control in the landscape. Fill in low spots, create slopes and shallow trenches within the landscape to carry water away from structures. Amend compacted soil with compost or humus. Replace concrete areas with pavers, bricks or decomposed granite that will allow water to percolate into the soil below.

High winds: Support smaller trees with two stakes placed just outside the root ball to the west/northwest side of the tree, the direction of the prevailing winter storm winds in the Central San Joaquin Valley. When planting new trees always position the tree so that the heavier side with more branches or bigger branches is to the northwest, to help balance the tree against the wind. Plan on regular pruning to remove broken, dead or diseased branches and to correct weak branch structures.

Heat spikes: Deep irrigate a day or two before a heat spike, or several consecutive days of temperatures above 100 degrees, is predicted to arrive. Plan on hand watering container plants twice a day during long hot spells. Move containers into the shade during hot spells and provide afternoon shade for crop-producing plants with movable shade structures.   

Wildfire smoke and ash: Wash off ash and dust from trees and bushes frequently and try to direct the water into planting beds. Cover crop-producing plants temporarily with tarps or row covers to keep pollutants from tainting the fruit or vegetables. 

Long cold spells: The longer cold season this year really disrupted the (used-to-be) normal spring flowering schedule and delayed planting time for warm-season vegetables and flowering annuals. Transplants and seedlings were stunted by the cold and did not recover full vigor until mid-summer, so ripening and harvest have also been delayed. Home gardeners who compete to bring in the first tomatoes in summer or serve the last tomatoes for Thanksgiving in November may need to invest in heat-retaining row covers or heat-reflecting mulches and materials.

UC Master Gardener Richard Gillispie has two words of advice for Fresno County gardeners: “plant lavender.”

That's what he did in a big way when the COVID-19 pandemic thwarted plans to travel in his brand new fifth-wheel RV during retirement. Working alongside his nephew on western Fresno land that has been in the family for 90 years, Gillispie collected, propagated and planted 38 species of the fragrant herb.

Gillespie's fascination with lavender was sparked by his honey bees' keen interest in the plant. He took a self-paced online lavender class at Michigan State University, then converted a field where his father once cultivated cotton into waves of gray-to-green shrubs that radiate a sweet floral aroma.

Caring for lavender is relatively easy. It tolerates poor soil and suffers from few pests and diseases. A perennial, lavender can live in the garden for a decade or more. The plant needs a small application of fertilizer for establishment but, when mature, does not need fertilizer to be applied.

Lavender is naturally drought tolerant. “Too much water will rot the roots,” Gillespie said. “The plants tell you when they need water. As a general rule, soak once a week, then leave them alone.”

In addition to honey bees, lavender attracts butterflies, hummingbirds and other pollinators. With many pollinators threatened by habitat destruction and climate change, lavender plantings are a welcome resource for insects that are essential for food production.

Lavender appealed to Gillispie in part because of its many uses:

Medicinal: Lavender is good for mental health, Gillispie said. The components in plant aromas affect the nervous system and have a calming effect, providing excellent therapy for anyone with anxiety or hyperactivity disorders, he said.

Culinary: Lavender honey is a luxury item made by bees that forage the lavender flowers. Lavender can also be used in sweet and savory recipes. Gillispie said he grills white fish on lavender sprigs to infuse a spicy, minty note. Lavender can be used to flavor lemonade, teas, ice cream, cookies and many other foods.

Potential for value-added products: A wide variety of products can be made with distilled lavender flowers, such as essential oil, soap and lotion and hydrosol, the watery by-product of lavender distillation that can perfume the home, laundry, face and skin with a fresh clean scent.

Learn more:

• Fifteen varieties of lavender fill a four-by ten-foot plot at the Fresno County Master Gardener's Garden of the Sun, 1750 N. Winery Ave., Fresno. Varieties include the fragrant French lavender Mailette, delicate white flower-bearing Edelweiss, the extra-large-leafed Hidcote Giant, and three-foot-tall Fatspike. The garden is open to the public Mondays, Wednesdays and Fridays from 8 to 11 a.m.
• Cultural tips for growing lavender, UC Integrated Pest Management program
• Managing lavender pests, UC Integrated Pest Management program