Home & Garden

Gardeners, prepare to fight pests

Asian citrus psyllid infestations should be reported to the county agricultural commissioner’s office.
Asian citrus psyllid infestations should be reported to the county agricultural commissioner’s office. Courtesy University of Florida

On that infernal list of life’s certainties, add garden pests to death and taxes. Chewing, sucking, tunneling and spreading diseases, garden pests pose challenges every year. Mostly, we’ve been concerned about aphid, snails, whitefly and the other usual suspects. Tolerating a little damage is part of the gardening experience. An aphid has to eat, right?

Of late, however, Sacramento-area gardeners have been dealing with an especially obnoxious swarm of damage-doers.

State and county agencies are working to control infestations of even newer and more nefarious A-list pests, like the Japanese beetle, discovered in Sacramento County in 2010. This year Sacramento County will place more the 2,000 Japanese beetle traps.

It’s just a matter of time before Sacramento gardeners encounter the Asian citrus psyllid, which has afflicted Florida orchards. Add that to other A- and B-list pests, which may have hitched a ride to the region on ships or planes, especially on incoming plants. It is generally illegal for individuals to bring plants (and accompanying insects) into California from other states and countries, but as officials realize, not everybody knows or follows the law.

The good news is that pests have cycles and populations are up one year and down the next. The bad news is there are even more new and destructive invasive pests on the way. Sacramento County environmental horticulture adviser Chuck Ingels cited the spotted lanternfly, native to China and Southeast Asia, and fond of fruit and ornamental trees and grapes. It recently was discovered in Pennsylvania.

Sorry, there are no pest cease-fires in gardening. To help you get to know your enemy, we’re highlighting what we’re calling the Malevolent Seven.

Japanese beetle

Pest ID: Efforts to curtail the establishment of the Japanese beetle in California are epic. The pest is a handsome little devil, about 1/4-inch long and shiny green with copper-colored wings. It’s often confused with the hoplia beetle or the much larger green fruit beetle (an inch long). Japanese beetles damage hundreds of different plants, but some of its favorites are roses, grapes, cherries, peaches, plums, apples, raspberries, corn and zinnias. The larva does severe damage to lawns.

Control: Handpicking, one-by-one or shaking an infested stem into a container, is the most environmentally conscious control. Any neem-based product that contains azadirachtin can keep them away for 3 or 4 days at a time. More toxic pesticides also will kill bees, so proceed with caution on flowering and edible plants and always read the entire label instructions.

Complete information: www.cdfa.ca.gov/plant;

www.ext.colostate.edu/pubs/insect/05601.html

Spotted wing drosophila

Pest ID: A tiny fruit fly, only 1/16- to 1/8-inch long, that damages mostly cherries in the Sacramento area. It also can damage berries and, occasionally, plums, nectarines, figs and plumcots. If you discover maggots inside cherries, the culprit is the spotted wing drosophila. The maggots are white and about 1/8-inch long when mature. It’s not unusual to find more than one maggot in a single cherry. Look for them in spring once temperatures begin to exceed 60 degrees and again in fall.

Control: The spotted wing drosophila is a newcomer, and there is limited research on the effectiveness of pesticides. The timing for spraying is complicated by as many as 10 generations a year and because pesticides have no effect on the maggots, protected inside the cherry. Try excluding them with fine netting and harvesting early to save as many cherries as possible. Pick up all fallen fruit and dispose in sealed bags to help prevent infestations in following years.

Complete information: www.ipm.ucdavis.edu/PMG/PESTNOTES

Bagrada bug

Pest ID: A stink bug, native to Africa that prefers vegetables, ornamentals and your seedlings. It’s black with orange and white markings on a shield-shaped body. Bagrada bugs are about the same size as a lady beetle and can be confused with harlequin bugs, but are much smaller. Both adults and nymphs feed on flowers, stems, leaves and seeds.

Control: Handpicking if the populations are small enough. Bagrada bug has no known specific natural enemies in the United States and little is known about the effectiveness of pesticides in the home garden. According to University of California Integrated Pest Management, “Research focused on managing the pest organically on commercially grown cole crops suggests that pyrethrum may suppress adults while azadirachtin and insecticidal soaps may reduce populations of nymphs.”

Complete information: www.ipm.ucdavis.edu/PMG/PESTNOTES

Asian citrus psyllid

Pest ID: Deadly damage in a tiny package, the Asian citrus psyllid is about the size of an aphid. Feeding on all citrus varieties, the winged, mottled-brown psyllid causes distorted new leaves and stems. Also look for waxy deposits, honeydew and sooty mold. The most serious damage, however, comes from being a vector of the deadly citrus disease huanglongbing or citrus greening. The psyllid can inject the deadly disease while feeding on citrus trees. There is no known cure. The psyllid and disease is threatening the citrus industry and home gardens.

Control: Other than repeated and thorough applications of insecticidal soap, neem oil spray and horticultural oil spray (every 7-10 days), other options are more toxic and may also be harmful to pollinators. Those would include carbaryl, malathion and imidicloprid. Landscape professional have access to other chemical treatments.

Complete information: www.ipm.ucdavis.edu/PMG/PESTNOTES

Brown marmorated stink bug

Pest ID: A marbled-brown stinkbug, about 5/8-inch long, with two white bands on its antennae. The BMSB invades home and structures in winter and seeks host plants in spring. It damages a variety of fruits, vegetables, berries and also feeds on some trees, including Chinese pistache, redbud and Southern magnolia. Begin looking for them in gardens this spring.

Control: Another newcomer, which means pest and controls are still being researched. UC Integrated Pest Management says, “Most garden pesticides are not very effective against stink bugs, especially adults. ... Insecticides, including broad-spectrum, persistent materials such as pyrethroids, lower toxicity products such as oils, and botanicals such as pyrethrin or azadiractin, may provide some suppression of young nymphs.” Diligent hand picking will reduce light infestations, while row covers, hand picking and pheromone traps used together, can reduce heavy populations.

Complete information: www.ipm.ucdavis.edu/PMG/PESTNOTES

ucanr.edu/sites/sacmg

Citrus leafminer

Pest ID: The citrus leafminer showed up in great numbers last year and was a major concern of gardeners in the Sacramento area. It first was reported in Southern California in 2000 and has slowly moved up the state. New growth on the tips of citrus trees becomes distorted and curled and the leaves are marked by serpentine tunneling, which is the larva mining as it feeds. A moth, less than 1/4-inch long, lays the eggs. Unfortunately, the moth is rarely seen and once the larva enters the leaf, it’s protected from most pesticides. Citrus leafminer damage can stunt growth on young trees (less than 4 years old), but mostly the damage is cosmetic.

Control: While new leaves are horribly disfigured, leave them alone. The healthy parts of the leaf can still help the tree and pruning only will stimulate new growth that will be susceptible to more citrus leafminers. Heavy nitrogen feedings in summer and fall also will promote new growth and attract more leafminers. Most pesticides won’t harm the miners inside the leaf, so they’re useless. If you do use a pesticide, remember you’re using it on an edible crop.

Complete information: www.ipm.ucdavis.edu/PMG/PESTNOTES

Leaffooted bug

Pest ID: You may have seen groups of leaffooted bugs on tomatoes last year. They’re one of the easiest pests to identify with a flat, leaf-like segment on the hind legs and white markings across the wings. Related to the stink bug, it can grow to 1 inch long. Leaffooted bugs have been around a few years but were especially troublesome last summer. They feed by sucking juices from fruits, vegetables, nuts and ornamentals with a piercing mouthpart.

Control: Menacing-looking, but fairly harmless to plants unless there is a major infestation. Leaffooted bugs do little damage other than discoloring fruit where they suck out juices. Handpicking can be effective, but adults are good fliers and can easily escape. Spraying pesticides may be effective on the wingless nymphs, but is not recommended because of toxicity to bees and pollinators and on edibles.

Complete information: www.ipm.ucdavis.edu/PMG/PESTNOTES

Strategies for Dealing with Garden Pests

▪ Be vigilant and regularly inspect plants for eggs, insects and damage. The earlier you detect and ID a pest, the less damage to the garden.

▪ Handpicking is the least toxic control. Wear gloves if you’re squeamish.

▪ Educate yourself on the pests and treatments using research-based information, like University of California Integrated Pest Management “Pest Notes.”

▪ Don’t spray insecticides until you have a positive ID on the pest and you know which insecticide will be effective.

▪ If you do intend to apply insecticides, read and follow all label instructions and be mindful that pollinators may also be killed.

▪ Sacramento County environmental horticulture adviser Chuck Ingels and Ed Laivo, citrus expert and sales and marketing director for Four Winds Growers, suggest that gardeners employ narrow or low-to-the-ground growing techniques, like espalier training and fruit bushes, to exclude pests with covers and enable easier maintenance without pesticides.

Get help

▪ For Japanese beetle, Asian citrus psyllid and Bagrada bug sightings, call the Sacramento County Agricultural Commissioner office: (916) 875-6603. For other pests, call or bring samples to your county cooperative extension office.

▪ California Dept. of Food & Agriculture Exotic Pest Hotline: 1-800-491-1899.

▪ Report a pest online to the California Dept. of Food & Agriculture.

▪ Check the state’s online list of quarantines in your area (click on Quick Reference and scroll down)

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