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Attack of the hoplia beetles


What happened to this rose? Hoplia beetles attacked it. (Photos:
Debbie Arrington)
This pest loves to eat light-colored roses and other spring flowers



What’s eating your roses? If it’s early May in Sacramento, most likely you’ve been visited by hoplia beetles.

This pest loves light-colored roses, especially white, yellow, apricot or light pink. It chews round holes in the petals as it works its way to the tasty center. It likes the unopened buds, too. But it doesn’t eat rose leaves – just the flowers.

According to UC Cooperative Extension master gardeners, hoplia beetles also feed on the flowers of calla, citrus, irises, lilies, magnolia, olive, peonies, poppies and strawberries, and on the young leaves and fruit of almonds, grapes and peaches.

In other words, these beetles are hungry, destructive pests.

Members of the monkey beetle family, hoplias are common in our area from late March through May, depending on the weather. More than 300 species of hoplia are known. Our most common local hoplias are Hoplia callipyge . The adults are brown, oval and about 1/4 inch long.

The adult beetles can fly, which is how they made it to your roses. They over-winter in the larval or pupal stage underground in undisturbed areas, feeding on roots and decaying vegetation. They emerge from the soil as adult beetles with an appetite. After feeding for several weeks, they fly back to their nesting site to lay eggs.

This life cycle takes a full year, which is key to their control. They’re only a problem right now. By the end of May, they’ll have disappeared.

This hoplia was eating a rose Sunday in midtown Sacramento.
Because the beetle tunnels into the bloom, chemical pesticides are not effective – or necessary. The pesticide has to come in direct contact with the beetle to kill it. In addition, systemic insecticides aren’t effective because concentrations of the poison in the plant’s petals aren’t high enough to be effective.

When you see a rose or other flower with hoplias, cut off the whole bloom, drop it in a plastic bag, seal and dispose of it.

Or use the bucket method: Fill a 5-gallon bucket with soapy water. Then, shake flowers suspected of containing beetles over the bucket. The beetles will fall in and drown.

Hoplias are attracted to white, so try this trick: Fill white buckets (preferably 5-gallon) or other large containers with water; the important thing is that these containers are white. Add a few drops of detergent to the water to break surface tension. Place these beetle traps at several locations among your rose bushes. Thinking it's a giant white bloom, hoplias will fly into the white bucket and meet a watery death.

The other solution? Stick to red roses; hoplias don’t like red.

For more information on hoplia beetles, check out the UC Integrated Pest Management pest notes at:
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7499.html

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Garden checklist for week of May 31

Remember to water early. No more rain is in the immediate forecast.

* It’s not too late to transplant tomatoes, peppers, eggplant or other summer favorites. Make sure they stay hydrated.

* From seed, plant corn, melons, pumpkins, radishes, squash and sunflowers.

* Plant basil to go with your tomatoes.

* Transplant summer annuals such as petunias, marigolds and zinnias.

* It’s also a good time to transplant perennial flowers including astilbe, columbine, coneflowers, coreopsis, dahlias, rudbeckia, salvia and verbena.

* Let the grass grow longer. Set the mower blades high to reduce stress on your lawn during summer heat. To cut down on evaporation, water your lawn deeply during the early hours of the morning, between 2 and 8 a.m.

* Tie up vines and stake tall plants such as gladiolus and lilies. That gives their heavy flowers some support.

* Dig and divide crowded bulbs after the tops have died down.

* Feed summer flowers with a slow-release fertilizer.

* Mulch, mulch, mulch! This “blanket” keeps moisture in the soil longer and helps your plants cope during hot weather.

* Cut back fruit-bearing canes on berries.

* Feed camellias, azaleas and other acid-loving plants. Mulch to conserve moisture and reduce heat stress.

* Cut back Shasta daisies after flowering to encourage a second bloom in the fall.

* Trim off dead flowers from rose bushes to keep them blooming through the summer. Roses also benefit from deep watering and feeding now. A top dressing of aged compost will keep them happy. It feeds as well as keeps roots moist.

* Pinch back chrysanthemums for bushier plants with many more flowers in September.

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Dec. 16: Add asparagus to your edible garden

Dec. 9: Soggy soil and what to do about it

Dec. 2: Plant artichokes now; enjoy for years to come

Nov. 25: It's late November, and your peach tree needs spraying

Nov. 18: What to do with all those fallen leaves?

Nov. 11: Prepare now for colder weather in the edible garden

Nov. 4: Plant a pea patch for you and your garden

Oct. 27: As citrus season begins, advice for backyard growers

Oct. 20: Change is in the autumn air 

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Sept. 30: Seeds or transplants for cool-season veggies?

Sept. 23: How to prolong the fall tomato harvest 

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Sept. 9: How to get the most out of your pumpkin patch

Sept. 2: Summer-to-fall transition time for evaluation, planning

Aug. 26: To pick or not to pick those tomatoes?

Aug. 19: Put worms to work for you

Aug. 12: Grow food while saving water

Aug. 5: Enhance your food with edible flowers

July 29: Why won't my tomatoes turn red?

July 22: A squash plant has mosaic virus, and it's not pretty

July 15: Does this plant need water?

July 8: Tear out that sad plant or baby it? Midsummer decisions

July 1: How to grow summer salad greens

June 24:  Weird stuff that's perfectly normal

SPRING

June 17: Help pollinators help your garden

June 10: Battling early-season tomato pests

June 3: Make your own compost

May 27: Where are the bees when you need them?

May 20: How to help tomatoes thrive on hot days

May 13: Your plants can tell you more than any calendar can

May 6: Maintain soil moisture with mulch for garden success

April 29: What's (already) wrong with my tomato plants?

April 22: Should you stock up on fertilizer? (Yes!)

April 15: Grow culinary herbs in containers

April 8: When to plant summer vegetables

April 1: Don't be fooled by these garden myths

March 25: Fertilizer tips: How to 'feed' your vegetables for healthy growth