A gardener’s work is never done. The battles with weeds may be slowing down, but now insect problems are on the rise. Aphids are sucking the juices from roses, curling the leaves of ash, cherry, dogwood and more. Last week I mentioned earwigs seem to be voraciously eating seedlings and young plants. I have found slugs on my iris. Cooperative Extension’s Horticulturist Wendy Hanson says sawflies are attacking Jeffrey pine and hollyhock weevils are out in droves.
What’s a gardener to do? For the least toxic methods, aphids can be hosed off daily or so with a blast of water, squished with your fingers or sprayed with insecticidal soap. They will be gone as the summer temperatures rise, returning mid- to late-August. Aphids prefer plant hosts with high nitrogen content and lots of new growth. Try using slow release fertilizers on susceptible plants.
Yes, we have slugs in Nevada. They are not insects, but mollusks. They feed on many species of plants near the ground chewing holes in the edges of leaves and fruits. Wet humid conditions encourage slugs, so don’t overwater and water early in the day to allow foliage to dry by evening. Reduce hiding places such as debris, dense ground covers and weedy areas. Flat containers of beer buried level with the soil attract slugs and serve as a trap.
Conifer sawflies aren’t true flies. They are relatives to bees and wasps. Their caterpillar-like larvae often feed several to a needle or on young shoots. Pear sawfly larvae (pearslugs) look like slugs and skeletonize the leaves of most fruit trees, particularly pear and cherry. Healthy trees tolerate some defoliation by both types. Natural predators such as birds and parasitic wasps and even small mammals can keep populations in check. Clipping off infested foliage can work when larvae are on a small portion of the plant. Pearslugs can be hosed off.
Hollyhock weevils are small, about 1/8 inches, gray with orange legs. Their snouts are amazingly long, almost half their body length. These weevils eat the seeds, buds and tender leaves of hollyhocks. As the leaves unfurl, they are covered by numerous small holes. Manage them by shaking the plant over a sheet on the ground, picking up the weevils and destroying them. Regular removal of seedpods will eliminate developing larvae.
Healthy plants tolerate insects. Insecticides are rarely needed to manage many insect infestations. If you have questions email me or call me at 887-2252.