Bagrad crop pest Cabbage family

Exotic bug is threat to cabbage-family crops

Bagrada’s needle like mouth sucks juice from tissue of plants Bagrada bug has shown up in many inland gardens

Large populations of an exotic insect pest, the Bagrada bug, also known as painted bug or harlequin bug, appeared in many inland gardens this summer. The bug is native to Africa, and it was first found in California in June 2008 in Los Angeles County. It spread rapidly and is now widely distributed throughout much of Southern California.

The Bagrada bug is a major pest of crop plants in the cabbage family, which also includes broccoli, cauliflower, kale, radish and turnips. Other crop hosts include papaya, potato and legumes.

The bug has needlelike mouth parts that it uses to suck juices from plant tissue. This produces large stippled or wilted areas on leaves and stunted growth on the developing central shoots or heads of plants.

Adult Bagrada bugs are about one-fifth- inch long and have shiny black shield-shaped bodies with distinct white and orange markings. Adult females lay eggs in the soil under host plants and on foliage. Populations can build up quickly and usually peak in late summer or early fall.

Bagrada has few natural enemies in our area, and chemical treatment may be needed to control large populations on crop plants. Before any insecticide is used, carefully read the product label to be sure it is safe to use on the plants you wish to treat. Insecticides that may help control the pests include pyrethrin, Neem Oil, insecticidal soap, Spinosad and carbaryl (Sevin).

Q: My 38-year-old grandiflora rose was 9 feet tall and covered with huge prolific blooms. Our gardener lopped off the top of the bush and it is now, barely, 5 feet tall. Did he ruin the rose, or is there something I can do to restore its former beauty?

A: Your rose should survive and, in time, regain its former stature and beauty. Giving the rose a little fertilizer and a thorough irrigation should help it recover. Be careful not to water the rose too often. Keeping the soil too wet could damage its roots. The severe pruning and loss of foliage will temporarily reduce the amount of water it uses.

If your rose has pink flowers, it may be an old variety, ‘Queen Elizabeth,’ according to Roger English, a rosarian and past president of the San Diego Rose Society. He recommends re-cutting the canes about a quarter-inch above a leaf with 5 leaflets or a bud facing in an outward direction. Leaving a long stub could lead to dieback and decay of the stem. If no leaves are present on the stem and the location of buds is not obvious, it may be better to wait until new shoots appear, and then cut the stem above the most desirable one.

Q: Some type of borer has attacked my peach tree. Will a dormant oil spray kill the pests? I want to keep the borer from spreading to my newly planted plum tree.

A: Several insect species can bore into the trunk, branches or shoots of peach and other deciduous fruit trees. I can only provide general information without knowing which insect you have.

Horticultural oils are contact insecticides, and spray must get on an insect to kill it. Borers feeding beneath a tree’s bark will not be controlled by an oil spray. Other insecticides, including products with systemic activity, are also not very effective against borers.

Branches that have been severely damaged by borers should be pruned out during the winter.

Borers often attack trees that are injured or not growing well due to inadequate soil moisture or fertility, severe pest or disease injury, root damage or old age. Select varieties well adapted to your area’s climate and plant them in well-drained soil. The bark on young trees should be protected from sunburn damage, which can weaken trees and create wounds that attract the Pacific flat-headed borer. You can protect the bark by painting the trunk with a whitewash consisting of water and an equal amount of white, flat interior latex paint. Adequate irrigation is essential to keep fruit trees healthy and vigorous. Water newly planted trees often enough to keep their small root systems from drying out. Established trees should be irrigated periodically during dry weather, and enough water should be applied to wet the soil about 2 feet deep.

Q: Indian Stick insects have invaded my Point Loma neighborhood. When I hand-water my plants, the insects move around and are easy to spot so I can pick them off and crush them. My garden is designed to attract butterflies and hummingbirds, so I don’t use pesticides. Is there a predator or natural product I can buy to control the pests?

A: The Indian Stick insect is an exotic pest. It does not have any effective natural enemies here, and I do not know of any predators you can buy. Hand picking is probably the best non-chemical method to control the pest. Indian Stick insects are difficult to see during the day when they hide among plant stems and remain still. Sprinkling plants with water disturbs the insects and some will move to the exterior of a plant. They can be picked off and crushed or dropped in a container partially filled with soapy water.

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