Home & Garden

Learn how some insects can be beneficial to plants

A lady beetle feeds on mealy plum aphids at an orchard of French prunes
A lady beetle feeds on mealy plum aphids at an orchard of French prunes Fresno Bee File Photo

What should we plant this spring when we’re expecting another drought year?

Elinor Teague

Some very attractive flowering plants, including many drought-tolerant species, should have first place on the planting list because they provide habitats or food for several important beneficial insects. Stressed plants attract pest insects, especially soft-bodied aphids, mealybugs, immature scale, whiteflies and mites. We can expect that our plants will be drought and heat-stressed this summer. Having a home-grown supply of beneficial insects at hand to keep pest insects under control can reduce the need to apply pesticides in our gardens.

The lists of host plants for lady beetles, lacewings and syrphid flies (hoverflies) are very similar, and some of those best suited for our climate are grouped below.

▪ Lady beetles: Also commonly called ladybugs, lady beetles and their larvae are voracious aphid predators. Lady beetle larvae look like tiny gray and orange alligators, and they can consume 100 aphids a day. The adult females lay their yellow eggs near aphid colonies in spring and the eggs hatch within three to five days, just in time for the aphid population explosion. Lady beetles will escape the summer heat and fly to the foothills where they overwinter and return to the Valley the following spring.

▪ Lacewings (green or brown): The tiny brown lacewing larvae, which also look like little alligators, are often referred to as “aphid lions”; they’ll eat 200 aphids or soft-bodied insects and their eggs a day. The larvae feed for one to three weeks before becoming adults. The adults feed on pollen and nectar and are beneficial pollinators. The very pretty lacewing adults fly on spring and summer evenings, attracted to the light from our windows.

▪ Syrphid flies (hoverflies): Syrphid flies are such fun to watch at work in the garden. They resemble small brown or black bee-type insects with yellow and black markings but only two wings. Syrphid flies can hover and fly backward and horizontally. The pollinator adults feed on nectar and pollen and lay a single white egg near aphid infestations or near leaves covered with aphids’ sticky honeydew or excretions. Each slug-like maggot or larva can consume up to 400 aphids or ant or termite eggs, small caterpillars and thrips during that developmental cycle. The larvae turn into pupa and overwinter in tiny cocoons.

Learn to identify the adult and larval stages of beneficial insects in your gardens and avoid spraying pesticides, insecticidal soaps or horticultural oils when you see them in your garden.

This partial list of host plants includes many with umbrella-shaped flowers, favorites of beneficials and pollinators:

Ajuga, alyssum, artemisia, carrot flowers, cilantro, cosmos, dandelion, dill, fennel, goldenrod, lobelia, marigold, mint, parsley, Queen Anne’s lace (invasive), rudbeckia, yarrow

Note: The Clovis Botanical Garden’s annual “Spring into your Garden” festival will be held rain or shine this Saturday from 10 a.m.-2 p.m. at 945 N. Clovis Ave. There will be a water-wise plant sale, garden tours, vendors, exhibitors and children’s activities. Admission is $5 for adults, free for children and CBG members.

Visit www.clovisbotanicalgarden.org for a complete event schedule.

Elinor Teague: etgrow@comcast.net