If your petunias and geraniums are budding but won’t bloom, the reason could be the tobacco budworm also known as the geranium or petunia bud worm.
Life Cycle of a Bud Worm
Here’s what they do. The adults start to emerge as a tan to brown small moth mid-March through mid-April. They seek out the buds of flowering plants or the terminal growth (the ends of new growth) where they lay an egg. They will lay many eggs over their short lifespan. After a short time, the egg will hatch and the larvae will instinctively bore into the end of the bud where they will devour the blossom from the inside. The larvae are yellow to green in color but will take on the color of the blossom they just ate. Red geraniums will turn the larvae red. They will emerge from the bud and slowly make their way to the soil, eating any tender growth they can find on the way down. In the soil they will start the pupation process and turn into an adult moth and the cycle starts all over again. There might be as many as five generations in one summer.
What Do Bud Worms Like to Eat?
Although the budworm moth was known to only inhabit the southern regions of the country, they are creating quite a problem for gardeners in the Northwest. They have been quite successful over-wintering in the soil as a pupa. They will attack almost any tender flowering plant but they are best known for eating the buds of petunias, geraniums, and nicotiana plants. They will also go after many vegetables, especially cabbage.
How to Get Rid of Bud Worms
Almost any insecticide will kill the budworm when it’s actively feeding but won’t do anything to the moth or pupa. A bacteria known as spinosad (spin-OH-sid) will attack the budworm throughout all stages of life. The most commonly known product that contains spinosad is Captain Jack’s Dead Bug Brew. Just spray it on once every few weeks and the problem is solved. Call or stop by our Portland garden center to learn more about your options!