It’s the time of the year when our national flower put on a dazzling show, cloaking plants with brilliantly colored, sweet-smelling blossoms. Are your plants bedecked with perfectly formed flowers, or by chance do you see what way too many gardeners do come June, roses with petals that resemble Swiss cheese, young buds that have dried up, or stems that are broken just below the bud? If so, your garden may be home to the weevil of rose destruction – the rose curculio.
These real bad guys of the garden, if left uncontrolled, can decimate your springtime rose blooms and wreak havoc on other hosts like blackberries, boysenberries, and raspberries. Ragged blossoms, deformed flower buds that fail to open, gouges in buds stems that cause them to shrivel and die, rose stems with “bent necks” and damage to the reproductive portions of the flower are symptoms of this garden marauder.
Generally showing up in late May and June, the beastly quarter-inch long rose curculio or rose weevil is a dull lacquer red with a set of antennae midway up their characteristic narrow, black, curved snout. These chewing insects “drill” small holes in rose buds or tender stems to feed. The small, legless white larvae gnaw on blooms and the reproductive parts of the flower, seeds and to some extent petals as they develop, then drop to the ground to pupate in soil over the winter. Emerging as an adult in late spring, they crawl up to feed on flower buds and starting the reproductive cycle once again. Generally, there is only one generation a year.
Though the damage done by these weevils is generally aesthetic, serious infestation can prevent almost all bloom. The most effective means of reducing or eliminating them is to hand-pick and destroy them. A small container of soapy water works well. Inspect the plant and when you see one of these pests, hold the container underneath it; the curculio plays dead when disturbed and drops off the plant to avoid capture, right into the soapy trap. Late morning is a great time to pick them off as they’re a bit more sluggish. Move slowly to surprise them before they take flight. To reduce future generations, remove spent blooms and hips, along with any damaged blooms and discard them in the trash; don’t add to the compost pile.
By Nanette Londeree, Master Rosarian