How To Prevent and Control Budworm Damage
GARDEN TIPS
Bedding plants like geraniums, petunias and nicotiana can create a riot of color when planted en masse, but gardeners aren’t the only ones drawn to these bright and prolific flowers. Feeding damage caused by budworm caterpillars is on the rise across the country, causing alarm and panic in the gardening community — so much so that some gardeners are refusing to grow the most frequent plant victims of budworm damage.
What are Budworms?
Budworms are moth caterpillars that chew their way into the tightly coiled buds of flowers and slowly eat them from the inside out. Budworm caterpillars start life as tiny larvae that measure less than 1/16 inches long, but grow up to 2 inches over the course of the summer. These larvae start out cream colored with brown heads and light colored stripes, but mature into colors ranging from green to rust to black. Identification should be simple — they’ll be the caterpillars eating your flowers from the inside out.
Budworm
Budworms feed on all types of vegetative buds, but primarily focus on flower buds and maturing ovaries. Flower buds often fail to open, but those that do look ragged from all the petal chewing. As the summer progresses, the damage gets more severe. Fortunately, these pests only feed for about a month before dropping into the soil to pupate, giving your flowers a chance to recover. Two generations a year are common, with the second generation being much more damaging than the first.
“Controlling budwords is all about timing.”
How to Kill Budworms
Controlling budworms is all about timing. Since the larvae spend most of their time protected by the buds where they feed, treatment after hatching does little good to destroy populations. Instead, applying pesticides before hatching or to newly emerged caterpillars is the best solution.
Synthetic pesticides like permethrin, esfenvalerate, cyfluthrin, and bifenthrin require fewer applications because they last longer in the environment, but they can be dangerous to beneficial insects like bees, especially if part of your flower garden is already in bloom.
Bacillus thuringiensis (Bt) can be used safely against budworms, but timing is everything. Monitor your plants carefully for larval emergence and apply Bt as soon as the first few eggs start to hatch. Bt has a very short life when exposed to air, but it will target the caterpillars without damaging other insects.
Other, safer methods of control include checking buds for tiny holes and removing those that are infected in hopes of breaking the life cycle. Cold winters are believed to be devastating to pupating budworms, allowing potted plants to experience temperatures of 20 F. (-6 C.) and lower can reduce the next season’s budworm population.
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Great article. So helpful. Thank you.
Do we apply Bt to the soil if that’s where the eggs are?
No, BT has to be eaten by the caterpillar.
So we apply it to the flower buds then?
Yes apply to flower and buds it is safe to smoke and will rid of them
Safe to smoke???
I have a terrible 2nd infestation going. I have also struggled with Aphids and probably cucumber beetles this year. I usually don’t toss all of the soil in my planters every year, but should I be?
Neither of those insects would overwinter, but for better plant health replace as much soil as possible.
Can I bake my old soil in myout door oven and kill the eggs and use the soil next season?
because the soil is expensive.
Yes but you would still want to mix it with fresh soil.
Almost all the buds of all my roses were destroyed while they were still so tiny that I hadn’t noticed they had started to grow. The eaten off ones I found later were less than 1/8 of an inch. The one rose that managed to get buds past that stage, the buds were consumed from the inside, as described in this article. Am I right to think this was all the work of hte budworms?
Yes what you’re describing sounds like caterpillar damage. Use Eight to control them.