Tips to combat the ferocious Bagrada bug

Q: Can you tell me what options I have for combating the ferocious Bagrada bug?

A: The Bagrada bug, from the stink bug family, is a  1/4 -inch in size. It is black with orange and white markings with a shield shaped body. And it is an eating machine. The bagrada bug hails from Africa and the Middle East. It was first discovered in the United States at a Los Angeles port in 2008 and it made its way to San Luis Obispo County by September 2012.

It overwinters on hillsides of mustard or pepper weeds and becomes active when temperatures rise to 85 degrees or warmer. Its preferred diet includes plants in the brassica family such as broccoli and cauliflower, but it will also feed on radishes, alyssum, nasturtiums and others. You can easily identify the star-shaped lesions that result from its feeding on plant leaves. They also feed on seeds, flowers and stems.

This stink bug family member has no effective natural enemies in the USA. It lays eggs mostly in the soil where parasitoid wasps can’t easily get to them. Some spiders may feed on them, but birds detest the foul smelling liquid the Bagrada secretes when attacked.

So what can you do in your home garden?

Because Bagrada bugs are active during the warmer part of the day, check your plants during that time. Unfortunately, by the time Bagrada adults — or their red-colored nymphs — are spotted, the population may be too high to pick them off by hand.

One effective “mechanical” control method is vacuuming the bugs. Put cardboard or plastic under the affected plant, shake it, and use a handheld vacuum to suck them up. If the plant is already defoliated, dispose of the plant and bugs using a large garbage bag that is tightly secured.

You can also buy a stink bug or pyramid trap. But instead of the chemical lures, which will not work for the Bagrada bug, use crushed sweet alyssum to lure it into the trap. Spraying insecticides is not very effective because the adults are able to fly off without injury and the eggs are safe in the soil.

A reliable method to control almost any insect infestation is figuring out a way to prevent the problem. Use small screened growing tunnels or floating row covers to protect your seedlings and young plants, tucking in the edges so no Bagrada bug can intrude.

Jetta Thornier is a UCCE Master Gardener.

This story was originally published October 5, 2016 at 5:12 AM with the headline "Tips to combat the ferocious Bagrada bug."