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Attack of the hoplia beetles

Sacramento Digs Gardening
BY Debbie Arrington PUBLISHED MAY 4, 2020

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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GENERAL GARDENING

An article about gardening.

Keywords:

UCCE master gardeners hoplia beetles gardening Sacramento integrated pest management insecticides pest damage pests roses spring flowers UC IPM

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Garden Checklist for week of Nov. 3

November still offers good weather for fall planting:

* If you haven't already, it's time to clean up the remains of summer. Pull faded annuals and vegetables. Prune dead or broken branches from trees.

* Now is the best time to plant most trees and shrubs. This gives them plenty of time for root development before spring growth. They also benefit from fall and winter rains.

* Set out cool-weather annuals such as pansies and snapdragons.

* Lettuce, cabbage and broccoli also can be planted now.

* Plant garlic and onions.

* Keep planting bulbs to spread out your spring bloom. Some possible suggestions: daffodils, crocuses, hyacinths, tulips, anemones and scillas.

* This is also a good time to seed wildflowers and plant such spring bloomers as sweet pea, sweet alyssum and bachelor buttons.

* Rake and compost leaves, but dispose of any diseased plant material. For example, if peach and nectarine trees showed signs of leaf curl this year, clean up under trees and dispose of those leaves instead of composting.

* Save dry stalks and seedpods from poppies and coneflowers for fall bouquets and holiday decorating.

* For holiday blooms indoors, plant paperwhite narcissus bulbs now. Fill a shallow bowl or dish with 2 inches of rocks or pebbles. Place bulbs in the dish with the root end nestled in the rocks. Add water until it just touches the bottom of the bulbs. Place the dish in a sunny window. Add water as needed.

* Give your azaleas, gardenias and camellias a boost with chelated iron.

* For larger blooms, pinch off some camellia buds.

* Prune non-flowering trees and shrubs while dormant.

* To help prevent leaf curl, apply a copper fungicide spray to peach and nectarine trees after they lose their leaves this month. Leaf curl, which shows up in the spring, is caused by a fungus that winters as spores on the limbs and around the tree in fallen leaves. Sprays are most effective now.

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